Issuu on Google+

PRACTICAL COURSE

HOROLOGY


From

the collection of the

^

m

Prelinger ^ D

Jjibrary t

P

San Francisco, California 2008


A PRACTICAL COURSE

IN

HOROLOGY


A PRACTICAL COURSE IN

HOROLOGY By

HAROLD C KELLY

Head, Department of Horology Southwestern Institute of Technology Weatherford, Oklahoma

THE MANUAL ARTS PRESS PEORIA, ILLINOIS


Copyright, 1944

THE MANUAL ARTS PRESS

No

part of this book

may

be reproduced in any

form without permission of the copyright owner 34KS5

PRINTED IN THE UNITED STATES OF AMERICA


CONTENTS

"TIME'' Poem, by Laurens L, Simpson

.

.

Preface

7

9

PART

I:

GENERAL PRINCIPLES

Chapter

ONE.

Wheel Work

13

TWO.

Gearing

32

The Lever Escapement

39

THREE. FOUR.

The Controlling Mechanism

PART

II:

...

52

PRACTICAL REPAIRING

ONE.

Train Problems

62

TWO.

Jeweling

6^

THREE. FOUR. FIVE. SIX.

SEVEN.

Making a Balance

Staff

72>

Pivoting

85

Fitting Balance Springs

88

Escapement Adjusting

100

Cleaning and Oiling

124

5


PART

III:

ADJUSTING

ONE.

Preliminary Notes on Adjusting

TWO.

Position Adjusting

.

.

128

140

THREE.

Adjustment

to Isochronism

.

.

.

.150

FOUR.

Adjustment

to Temperature.

.

.

.156

.

.

.

FIVE.

Practical

Work of Adjusting

159

Glossary of Terms

173

Bibliography

182

Index

185

6


TIME BY Laurens L. Simpson (written to accompany the gift of a watch)

• /

am

I

come

time. to

give thee life

Twenty-four hours of every day, All this to every man. I tick

tick.

I sound in peace, and strife,

In

sleep, in

work and

play.

Forever, on and on. I never change

To good and had alike. The rich, the brave, the All use

I

am

To

me

as they may.

gold

who who do

those

Lead,

The

free

will; to others

not see

benefit of industry.

am power. Weak to strong, coward

I

Man

grows as I move

Or not,

to brave,

on,

as will he may.

(continued next page) 7


I

am fame

To

those

Who

whose

shine with

light is bright, all their

might,

Pure, through day and night. I

am

To

happiness

those

Who

who

serve and give,

help the weak, mxike

The unknown, and

Now

live.

or never

Equal chance I give

My

known

days

to

use or

lose.

Here once then gone

8

to all,

forever.


PREFACE The

art of horology unquestionably ranks among the

most wonderful of the mechanical at the diminutive size of the

arts.

One can

only marvel

modern wrist watch and the

accuracy of the machines by which the duplicate parts are

made. Production and improved manufacturing methods have also changed the repairman's approach to horology. licate parts are available, so the horologist is

upon

to

make a

part.

However,

Dup-

seldom called

since the sizes of watches

have been reduced, new tools and improved methods are essential to

good workmanship.

skill in fitting staffs to small,

One must

develop a greater

uncut balance wheels, in adjust-

ing small escapements, and in handling the new, alloyed balance springs.

The purpose

of this book

is

to present the fundamentals

of horology, both in theory and practice.

Part 1 deals with

wheel work and gearing, which involve the work of calculating the number of teeth of missing wheels and pinions and in determining their proper diameters.

ment design and an

Principles of escape-

analysis of the balance

given considerable space.

and spring are

Part 2 treats repair methods, in

which the making of a balance

staff

and the adjustment of

the escapement are given more than the usual space allotted

ments to

Part 3

is

concerned with the adjust-

position, isochronism,

and temperature, factors that

to these subjects.


A PRACTICAL COURSE IN HOROLOGY

10

may

be called the finishing touches of the horological pro-

fession.

The author is indebted to T. J. Wilkinson and C. E. DeLong for the reading of parts of the manuscript and for helpful suggestions. The chapter on wheel work is based on a system by Jules Grossman, ical

late director of the horolog-

school of Locle.

It is

hoped that

this

work

will contribute

some small part

toward the development of a generation of capable and well equipped horologists.

HAROLD

C.

KELLY


PART

1

GENERAL PRINCIPLES


Parti

CHAPTER ONE

Wheel Work Terminology

Wheel work

is

the basis for the construction of

struments for the registering of time.

one of the

earliest

Even the

these early clocks as well as those of the filed

clepsydra,

forms of a clock, which operated by the

dripping of water, involved the use of wheels.

were

all in-

first

The wheels

of

pendulum clocks

out by hand and although the workmanship on some

of the later creations was quite skillfully executed, they were, of course, very crude as compared with the machine-made

wheels of modern clocks and watches.

Since wheels are

fundamental to the construction of watches,

we have

decided

that this opening chapter shall be given over to the consideration of wheels as they apply to the science of horology.

low are

Be-

listed several definitions relative to the subject:

Wheel: any circular which teeth may be cut

piece of metal on the periphery of

of various forms and numbers.

Pinion: the smaller wheel with teeth called leaves, working in connection with a larger wheel.

Train: a combination of two or more wheels and pinions, geared together and transmitting power from one part of a

mechanism

to another. 13


A PRACTICAL COURSE IN HOROLOGY

14

a circular box of metal for the reception of the

Barrel:

main

spring.

Balance: the vibratory wheel, which, the balance spring, controls the

Balance spring: a

movement of

fine, coiled wire,

with

in connection

the hands.

one end of which

is

attached by a collet to the balance staff and the other end to

some stationary part of the watch through the medium of a piece called a stud.

Beat: resulting

one vibration of the balance and balance spring

from an impulse received by means of an escape-

ment.

Escapement:

includes

those

parts

a watch which

of

change the circular force of the escape wheel into the vibratory motion of the balance. Pallets:

that part of

an escapement which receives im-

pulse from the escape wheel and by

impulse to the balance.

means of a

lever delivers

This term includes the

pallet

arms

and jewels. Receiving pallet:

that pallet stone over

which a tooth

of the escape wheel slides in order to enter between the pallet stones.

Discharging pallet: that pallet stone over which a tooth of the escape wheel slides in order to leave from between the pallets.

Lock: on a

the overlapping contact of an escape wheel tooth

pallet stone's locking face.

Watch Trains Since the motive force stored In the main spring of a

watch does not

act directly

on the balance,

it is

by necessity


:

WHEEL WORK

15

transmitted by a system of toothed wheels and pinions. This

system of wheels and pinions, commonly called a

train, is a

mathematical assemblage of mobiles, and anyone

scientific,

who becomes familiar with the principles much satisfaction from such knowledge.

involved derives

we have two trains, the main train and the The main train changes a slow motion into a

In watches dial

train.

fast

one with the particular purpose of causing the wheel

make one turn in the same escapement makes a required number of beats.

that carries the minute

time that the

The

dial train,

hand

to

on the other hand, changes a

fast

motion

Into a slow one for the purpose of governing the distance the

hour hand travels to one turn of the minute hand.

The Main Train Calculating the to obtain the is

geared,

we

number

of turns of a pinion.

number of turns of a pinion divide the

into

In order

which a wheel

Q

num-

ber of teeth in the wheel by the

number of

leaves in the pinion.

Suppose, for example, a wheel of 72 teeth gears into a pinion

of 12 leaves.

wheel as

B

Designating the

and the pinion into

which the wheel gears as Figure

1,

c,

the formula for the

problem reads as follows

B

— = number of turns of the

pinion.

Figure 1


:

:

:

A PRACTICAL COURSE IN HOROLOGY

16

Substituting

B — by

their numerical values

we have

c

72 — = 6 turns of the pinion to one of the wheel. 12

Calculating the

Most watch

number

of turns of a complete train.

trains contain five wheels, as

shown

in

Figure

2.

These include the main-spring barrel and the escape wheel,

and

all five

mobiles are usually

named as

B = barrel or first wheel C = center or second wheel

T = third wheel F=

fourth wheel

E = escape wheel The

pinions are as follows

= center or second pinion = third pinion = fourth pinion e = escape pinion

c t

f

Figure

2.

Main

train.

follows


WHEEL WORK It will first

17

be noted that the second pinion

pinion, but for convenience

as the wheel of which

it

is

it

is

is

in reality the

given the same

name

a part and referred to as the

center or second pinion.

As an example

of a

modern

train

we

shall select the

ber of teeth of wheels and leaves of pinions as

(Remember, the

barrel,

center,

wheels are indicated by the capital

and the

center, third, fourth

letters c, t,f

and

B

72

C

_80_

T

75

1 F

_

num-

shown below.

fourth and escape

third, letters

B, C, T,

F

and E,

and escape pinions by the small

e.)

^

lo"^ 80

Multiplying the numbers

6,

get 3,600, which represents the

wheel to one of the

8,

7j^, and 10 together

number

we

of turns of the escape

barrel.

Dividing 3,600 by 6 (turns of center wheel to one of the

we

barrel)

made by

number (600)

represents the turns

the escape wheel in one hour, since the center wheel

carries the

hour.

get 600. This

minute hand and, of course, makes one turn in an

Henceforth

all

calculations will be based

of the center wheel, and on this basis

we submit

on one turn the follow-

ing formula, in which, as above, the capital letters C, T, indicate the wheels pinions.

and the small

letters

t,

f,

F

e indicate the


:

:

:

A PRACTICAL COURSE IN HOROLOGY

18

CTF

= 80 X 75 X 80 = 600 turns of the escape wheel. 10

tfe

X

10

X

The fourth wheel seconds

8 in

watches designed to register

all

so constructed that a second

is

hand

is fitted

to the

extremity of a long pivot extending through a hole in the follows, therefore, that according to the accepted

It

dial.

plan for the division of time, the fourth wheel must

make

60 turns to one of the center wheel. Therefore

CT

= 80 X 75 = 60 turns of the fourth wheel. 10

tf

However,

X

10

this is not necessary in

no second hand, and

in

many

makes more than 60 turns shall

soon

to

watches where there

is

wrist watches the fourth wheel

one of the center wheel, as we

see.

Calculating the

number

The escape wheel in and delivers twice as many

of beats.

most watches contains 15 teeth

impulses to the balance, since each tooth delivers two impulses, first to the receiving pallet pallet.

Letting

E

and

later to the discharging

indicate the escape wheel

and

e the escape

pinion, the formula reads

CTF2E

= number of beats per ^ hour.

tfe

Substituting the numerical values

we have

80X75X80X2X15 10 X 10 X 8

= 18,000 beats per hour.

Fast and slow trains.

Not

per hour.

Some

watches make 18,000 beats

of the older watches

beats per hour, whereas

make

all

make 16,200 and 14,400

some newer American wrist watches

19,800 and 21,600 beats per hour.

There are other

trains of varying beats per hour, particularly

among

those


:

WHEEL WORK

19

Below are shown two examples of

of Swiss manufacture.

slow trains

X 72 X 2 X 10X10X8 80 X 75 X 80 X 2 X 80

X

75

15

== 16,200 beats per hour. 15

10X10X10 As

= 14,400 beats per hour.

already stated, watches without second hands

may have

any system of mobiles wherein the fourth wheel register seconds. all

Below are

will not

listed three trains of this type,

of which are fast trains used in small wrist watches.

54X 50X48X2 X

15

18,000 beats per hour.

6X6X6 64X66X60X2X15 =

8X8X6

42

X 42 X

35

X

35

X2X

19,800 beats per hour.

12

7X7X7X7 The

last train listed is

= 21,600 beats per hour.

unique in that the train has 6 wheels

with an escape wheel containing 12 teeth.

Comments on the fast trains. In the preceding paragraphs we discussed the slow and fast trains that have been in general use at various periods. We shall now consider further the

modern

fast trains

used to some extent

in

very

small wrist watches.

The watch

train

making 18,000

accepted as a sort of standard for

beats per hour has been

many

years.

However,

very small wrist watches making beats of various numbers per hour in excess of this figure are becoming more in evi-

dence and the increased use of such trains would lead one to inquire into the reason for their popularity.


:

A PRACTICAL COURSE IN

20

The reason

HOROLOGY when

the fact that 18,000-beat trains,

lies in

applied to very small wrist watches, have a tendency to set

on the locking. This

is

due to the fact that a

light balance

and a weak balance spring have not the necessary force to effect a satisfactory

come

unlocking of the escapement.

this fault of setting

on the locking,

it

reduce the drop lock to the very minimum. it

is

is

To

over-

necessary to

However,

since

expect the same precision of adjustment in

difficult to

small watches as offer a solution.

possible in larger watches, the fast trains

is

The

due to two factors:

make the unlocking easier more rapid motion of the bal-

fast trains

(1) the

ance and (2) the increased strength of the balance spring.

way

In this

the

new

fast trains permit a greater tolerance

with regard to the extent of the lock, resulting in a reduced tendency to set on the locking.

There

is

Better timekeeping results.

another point in favor of the

new

Every horologist has observed how often the

fast trains. coils of the

balance spring get caught in the regulator pins or get badly tangled due to a severe fast train

We

The

stronger springs fitted to

to eliminate the difficulty or, at

frequent occurrence.

Calculating the mobiles.

much

watches do

least, to lessen its

jolt.

number

now wish

and leaves of missing determine the number of teeth

of teeth

to

of wheels and leaves of pinions that are missing.

Let

F

indicate the missing fourth wheel of the following train

80

X

———

XFX2X 10X10X8 75

^

15 = 18,000

= 18,000 F = 80

225F

According to the above solution the fourth wheel contains 80

teeth.


1

:

:

WHEEL WORK In the next problem, the third pinion

21

is

mission. Letting

t

indicate the mission pinion, the equation reads as follows

—X

—=

2 X X 80 X ——t X 10 X 8

80

75

180,000

15

18,000

= 18,000

t

180,000= 18,000 18,000 t

=

1

180,000

== 10 leaves of the third pinion

Let us suppose that the complete fourth wheel and pinion of a wrist watch are missing in which is

The equation reads

the pinion.

54

XFX2X 6xf X6

X

50

2,250

F

-

15

F

is

the wheel and /

:

= 18,000

= 18,000

f

F

18,000

8

f

2,250

1

The

result

times as

many

nating / by

shows that the fourth wheel should have 8 teeth as the fourth pinion has leaves.

6, 7, 8,

or 10 leaves,

we may

Desig-

obtain any of the

following solutions.

48 "6"

64

80

'7 '¥

'To

56

Any

of the solutions given above

may

be used; however,

judging from the numbers of teeth and leaves of the train as

a whole, the most suitable numbers would be

F

48


:

:

A PRACTICAL COURSE IN HOROLOGY

22

There are times when the

ratios

For example we wish

numerator.

come out with a

fractional

to determine the

number

of teeth and leaves of a missing third wheel and pinion in

T

which

the wheel and

is

t is

the pinion.

-—X T X 48 X 2 X 15 = 18,000

54

tX6x6

2,160T

= 18,000

t

T

18,000

syi

2,160

"T"

T^ The

only numbers that

number of

fractional

may

be tried without producing a

teeth are

75 50 — and —

9

6

In this example the most suitable numbers would be

T

50

T~6~ There are other times when we arrive

at the

mediately, as in the case of determining the teeth of the escape wheel, E,

pinion,

90

answer im-

number

of the

and the leaves of the escape

e.

X 80 X 2E = 18.000 12 X 10 X e

X

80

9,600E

= 18,000

e

E

18,000

15

e

9,600

8

The answer shows

that the escape wheel contains 15 teeth

and the escape pinion 8

leaves.


:

:

WHEEL WORK new

Calculating a

number of

teeth for the wheels

pinions of a

new

small baguette

now wish

to determine the

and number of leaves for the

Let us suppose the watch

train.

is

to be a

making 21,600 beats per hour. Using the same

before to indicate the wheels and pinions the

as

letters

We

train.

23

formula reads as follows

CTF2E

= 21,600

tfe

We

may

number

decide in advance the

of leaves for the

number of teeth for the escape wheel. For the pinions t, f, and e we shall use 6 leaves each. The escape wheel will have 1 5 teeth. The equation now reads pinions and the

CTF2X

15

21,600

6X6X6 CTF =

21,000

X6X6X6 2X15

CTF= 155,520 CTF

The combined product of obtain the quantities desired,

number

into its

it

is

prime factors and

is

155,520.

In order to

necessary to resolve this to

three groups which will represent the

form these factors

numbers

into

for the teeth

of the wheels C, T, and F.

2)155520

2)

9720

3)

2) 777Q()

2)

4860

3)

2) 38880

2)

2430

2) 19440

3)

1215

405

5

Factoring,

we

find that

CTF

=

155,520

= 2^ X

3^

X

5.


:

:

A PRACTICAL COURSE IN

24

These factors may be formed binations, but the train

HOROLOGY com-

into groups of various

most suitable arrangement for a watch

would be as follows

C=

5X3X22 = 60 T = 33 X 2 = 54 F = 3 X 2^ = 48 Thus we show 60

X

54

X

the complete train.

48

X2X

15

6X6X6

= 21,600 beats per hour.

The Barrel and The

and

barrel

its

design of a watch. pinion must

Mainspring

mainspring are important factors

The

show a

Its

ratio

in the

between the barrel and center

definite relationship to the length

and

strength of the mainspring and must be determined with

mathematical exactness factorily

if

the watch

is

to

perform

satis-

and run a required number of hours.

Calculating the

number

of

hours a given watch will run.

In order to determine the number of hours a watch will run

we must to

first

find the

number of turns of the

one of the barrel. Letting

B

center pinion, the formula reads

center wheel

indicate the barrel

and

c the

:

B — = number of turns of center wheel

to one of the barrel.

c

Using a numerical example, we have

84 — = ^7 turns of center wheel. 12

Knowing it

that the center wheel

makes one turn

in

an hour,

follows that the barrel makes one turn in 7 hours.

Next


:

:

WHEEL WORK we must determine pletely

wind the

the

spring.

number of turns necessary to comA trial has shown that it takes 5^

turns to wind the spring.

run

will

is

25

The number

of hours the watch

found by multiplying 7 by 5^, thus

7X5^== 3Sj4 hours the watch will run. The mainspring should run hours; 36 to 40 hours

is

the watch not less than 32

better; in fact,

some of the

finest

watches will run 45 hours and more. Calculating the correct thickness of the mainspring.

We

experience no difficulty in fitting mainsprings to standard

makes of watches, for as catalogued

all

we have

to do

is

to select the spring

and graded by the particular manufacturer.

There are times, however, when an old watch or one of unfamiliar

make needs a new

the old spring

is

spring and,

not the correct one,

if

we

we need

suspect that

to apply a bit

of mathematical calculation to determine the correct thick-

ness of the spring.

In such cases the following method

is

suggested 1.

Divide the teeth of the barrel by the leaves of the center

pinion in order to determine the

one turn of the 2.

number of hours taken

for

barrel.

Determine the number of turns necessary to wind the

spring by dividing 36 (hours of running) by the

number of

hours consumed in one turn of the barrel. 3.

by

Measure the

inside diameter of the barrel

and divide

12.5. 4.

Divide the above quotient by the number of turns neces-

sary to wind the spring.

The

result

is

the thickness of the

spring.

Suppose for example that the

barrel, B, has

78 teeth and


:

A PRACTICAL COURSE IN HOROLOGY

26

the center pinion, the barrel 1.

is

c,

6.5

c

36

The

inside diameter of

12 millimeters.

—=— = 12

2.

has 12 leaves.

X

1

=6.5

hours,

= 5.5 turns to wind sprmg.

6.5

12

= .96

3.

12.5 •96 4.

= .17 mm., thickness of... the spnng.

5.5 It

should be understood that the answers are only ap-

proximate. In some cases, as in a a weaker spring

may

fine,

21- or 23- jewel watch,

be needed, whereas a 7- jewel watch

may

require a stronger spring.

Calculating the correct length of the mainspring. The proper length of the spring need not be calculated in so inches.

we may

Instead,

state that the spring should

many

occupy

one half of the area between the inside wall of the barrel

and the periphery of the arbor. If the spring does length

this,

the

is correct.

Observe that we say area and not space. The term space

would lead one

to infer that radial

measurements are

in-

tended, which would be incorrect, inasmuch as a spring

wound up would occupy more spring run down.

radial space than that of a

Thus, the statement often found in older

books on horology to the

effect that

we

allow one third of

the space for the arbor, one third for the space, and one third for the spring

is

slightly in error

a few coils too long.

The

correct rule should read

and indicative of a spring


WHEEL WORK One

third of the space is occupied by the barrel arbor

one half of the remaining area This

27

is clearly

shown

in

is

covered by the spring.

Figure

that the radial distance occupied

Figure

3.

It will

3.

by the spring

However

is less

the area of both spring

space are equal and

it

remains the same under

whether the spring

is

wound

Now

be observed than

Barrel showing correct space for mainspring.

that given to space.

or completely

and

let

all

and

conditions,

completely, partially

let

down,

down.

wind the spring

in the barrel

and

if

the spring oc-

more than one half of the area, break off the outer end and rewind in the barrel. When the correct area is cupies

determined the hook

is affixed.

A

contains from eleven to thirteen

spring of the proper length coils.

More than

the re-


:

A PRACTICAL COURSE IN HOROLOGY

28

quired number of coils only tends to increase friction and shorten the number of hours of running of the watch.

The Dial Train The cannon pinion, minute wheel, minute pinion, and hour wheel make up the dial train. Referring to Figure 4, the

Figure dial train is

4.

Dial train.

arranged as follows. The cannon pinion,

into the minute wheel,

the minute wheel

This latter wheel

is

M. The minute

pinion,

c,

gears

m, to which

attached, gears into the hour wheel,

fits

freely over the

cannon pinion.

H.

The

minute hand, of course, makes 12 turns to one of the hour

The formula

hand.

for the dial train, therefore, reads as

follows

HM =

12

cm number of teeth of pinions of a new dial

Let us suppose

we wish

to determine the

of wheels and the

number

of leaves

train.

We

shall decide

on 12 leaves for the cannon pinion,

c,


:

:

:

:

WHEEL WORK and 10 leaves for the minute

pinion,

29

m. Letting

H indicate

M the minute wheel, the equation reads HM = HM 12 cm 12 X 10 HM=12X 12X 10; HM = 1,440

the hour wheel

and

Factoring in the manner as heretofore explained,

we

find

that:

HM = 25 X

32

X

5

Combining these factors

to

form two groups representing

H and M we have H = 23 X 5 = 40; M = 22 X 32 = 36

the wheels

Thus the complete

train reads as follows

HM = 40 —X-- 36 cm

12

— =12 X 10

Various types of into three types:

minute wheel

to the

M_36_

(2)

may be grouped

the reverse, and

In the regular the ratio of cannon pinion

is

hour wheel

Dial trains

the regular,

(1)

(3) the irregular. to

dial trains.

and the

3 to

1

4 to

1.

is

ratio of the

minute pinion

H_l^_4

"c"~T2~

'

m"~10"""

In the reverse the ratio of the cannon pinion to minute

wheel

is

wheel

is

4

to

3 to

as

ratio of the

minute pinion to hour

1.

M_32_ T~'%~ The

and the

1

H_?l_^ '

m~"8"~

irregular does not belong to either of the above types,

shown by the following example

HM cm

35X48 14

X

10

48X26 13

X

8

32X45 12

X

10

12


—

:

A PRACTICAL COURSE IN HOROLOGY

30

Thus

the dial train

may

be formed by working out various

combinations, the only requirement being that the combined

The most

ratios equal 12.

4

to

1

used, however,

is

the 3 to

1

type referred to as the regular.

Calculating the teeth and leaves of missing mobiles. Let us suppose that the cannon pinion

is

missing from the

following train in which c represents the cannon pinion

54X32

CX12

= 12

i^ = 12 c

= 12c 12c = 144 c = 12

144

We

leaves of the cannon pinion.

now wish

hour wheel

in

to find the

which

number

of teeth of a missing

H represents the wheel.

H X 25 _ ^^ 10 X 10 ÂŤ = 12 4

H = 48 teeth of the hour wheel. Let us suppose that a complete minute wheel and pinion are missing in which

M

is

the wheel and

XM = 12 m 14

48

X

24

M = 12

7m

M

12X7 _ m"~~24

7 2

_3^ ~~ 1

m

is

the pinion.


WHEEL WORK The

31

shows that the minute wheel must have 3^^ times as many teeth as the minute pinion has leaves. Thus result

M_28_35_42_49 m~" 8"~10~12~~l4 Any

of the above solutions

may

be used as the following

equations will show.

48X28 14 X8

48X35

48x42

48x49

X

X

X

14

10

14

12

14

= 12

14

Problems 1.

What

2.

How many trains

3.

Name

4.

How many

is

meant by

train ?

Name

has the ordinary watch ?

the wheels of the average

main

them.

train.

turns does the escape wheel

make

center wheel in an 18,000-beats-per-hour train?

to one of the

How many

turns

in a 19,800-beats-per-hour-train? 5.

What

are the arguments in favor of the fast trains for very-

small wrist watches 6.

What

?

portion of the space between the barrel and the arbor

should the mainspring occupy ? 7.

What

is

the correct thickness of the mainspring

if

the barrel

has 80 teeth with an inside diameter of 13 millimeters and the center pinion has 10 leaves? S.

Name

9.

How many

10.

Name

the parts of the dial train.

turns does the hour wheel

make

in 12

hours

?

the various types of dial trains. Explain their difference.


Part I

CHAPTER TWO

Gearing Terminology Gearing constitutes a system of wheels and pinions whose circumferences are covered with teeth so that the

The

teeth of the wheel act

upon the leaves of a

function

a system of levers in which a longer

is

in reality as

lever presses

on a short one

until

pinion.

one lever ceases to press and

another lever comes into action.

Gearing

is

a rather technical subject and

study Figure

The terms given

5.

in

it Is

well

first

to

the illustration are

defined as follows:

Pitch circle: a a toothed wheel

circle concentric

and cutting

its

with the circumference of

teeth at such a distance

from

their points as to touch the corresponding circle of the pinion

working with

and having with that

it,

circle

a

common

velocity, as in a rolling contact.

Pitch diameter Full diameter:

:

the diameter of the pitch circle. the diameter

from point

to point of the

teeth.

Distance of centers: the distance measured on a straight line

from center to center between the wheel and pinion. 32


GEARING

33

a line drawn from center to center of

Line of centers:

any wheel and pinion. the pitch circle divided into as

Circular pitch:

many

spaces as there are teeth on the wheel or pinion.

divided into as

many

diameter of the pitch circle

the

Diametrical pitch:

spaces as there are teeth on wheel or

pinicn.

ADDENDUM DEDENDUM

Figure

Addendum:

5.

the portion of the tooth, either of wheel or

pinion, outside of the pitch circle.

Dedendum:

the portion of the tooth of either wheel or

pinion inside of the pitch

Driver

:

Driven:

circle.

the mobile that forces the other along. the mobile that

is

being forced along by the

driver.

Principles of Gearing

The addenda.

In Figure 6

A, representing the pitch portion of a circle

is

is

shown a portion of a

circle of a wheel.

another

circle,

gircle,

Rolling on this

B, the diameter of which


A PRACTICAL COURSE IN HOROLOGY

34

Figure

6.

Formation of the epicycloidal curve.

equals half the pitch diameter of the pinion.

If a pencil

point were fixed at the lowest point of the circumference of the smaller circle (the generating circle) and then rolled on

the larger circle without slipping, a curve would be traced

along the path of the line

The curve thus formed

C

in the direction of the arrow.

called the epicycloid

is

and determines

the shape of the addenda of the wheel teeth.

The dedenda. The dedenda by the same generating

The

smallef circle

of the pinion.

is

circle

of the pinion leaves

but not

rolled inside

is

formed as shown by the

A

Figure

7.

within a circle

A is

circle

line

and along the pitch

rolling

called a hypo-

cycloid and determines the shape

of

the

leaves.

pinion

dedenda of the pinion

Thus when a wheel and are made in conformance

with the above principles of de-

formed

same manner.

However, instead

of a curved line a radial line

in

in the

is

Figure

7.

circle


GEARING sign,

a smooth and constant force

Width

of tooth.

It

is

35

delivered to the pinion.

has been observed that the generating

forms one side of the tooth. The question now arises This is as to how to determine the width of the tooth. determined by dividing 360 (degrees in any circle) by the circle

number of

teeth in the wheel.

This gives us in degrees the

width of one tooth and one space, generally referred to as the circular pitch.

360

= 4.5 degrees circular

Thus

pitch.

80 teeth

The width pitch

;

of the tooth

the other half

is,

4.5 degrees

Therefore

is

equal to one half of the circular

of course, equal to the space.

= 2.25

2 of which 2.25 degrees

is

the width of the tooth and 2.25

degrees the width of the space.

Now, by

placing the generating circle, E, Figure

6,

with

the pencil point directly below and 2.25 degrees to the right

of curve C,

it

will be in position to trace out the other side

of the tooth by simply rolling the circle to the left as

by the dotted

C and The

line

The

D.

intersection of the

shown

two curves,

D, forms the point of the tooth. pitch diameter.

We now

wish to determine the pitch

diameter of a wheel and pinion, the center distance being

known.* The

first

procedure

is

to determine the diametrical

determined by means of a depthing tool, an instrument with adjustable male centers that can be adjusted to the holes in the plate and convenienth' measured with a micrometer or Boley gauge. *

The

center distance

is


:

:

:

A PRACTICAL COURSE IN HOROLOGY

36

pitch, the

formula for which reads as follows center distance

X

2 :

teeth of wheel

The

-j-

r-.

—=

.

,

.

,

diametrical pitch.

leaves of pinion

diametrical pitch

is

now

multiplied by the

number of

teeth in the wheel in order to determine the pitch diameter

manner the

of the wheel, and in like multiplied by the

number of

diametrical pitch is

leaves in the pinion to determine

the pitch diameter of the pinion.

For example, the center distance

is

8.5 millimeters

wheel has 80 teeth; the pinion has 10 leaves. the numerical values for the above formula,

80+10

;

the

Substituting

we have

= .1888 diametrical ^

pitch.

Continuing the problem we find that

= 15.104 mm. pitch diameter of the wheel. .1888 10 = 1.888 mm. pitch diameter of the pinion. 15.104+1.888 ^ ,^, „ = 8.496 mm., the distance between Proof: X X

.1888

80

^

,

,.

centers.

The

full

diameter.

quantity depending

The height

on the

of the addenda

ratio of the

is

a varying

wheel to the pinion,

but the production of theoretically correct gears or even

knowing when they

exist

is

not possible with the equipment

available to the practising horologist. to

add

The

usual practice

is

2.5 diametrical pitches to the pitch diameter of the

wheel and 1.25 to the pitch diameter of the pinion.* Experi* There

one exception to the above statement For the dial train where the pinions drive the wheels and the wheels drive the pinions, as in the case of setting the watch to time, the addenda is figured as 2 for both wheels and pinions. is


:

:

:

:

GEARING

37

ence has shown that the above figures are best for

all

practical

purposes.

We

found that the wheel has for

its

pitch diameter 15.104

millimeters and the pinion 1.888 millimeters.

The

diametrical

pitch multiplied by 2.5 gives us the height of the addenda

for the wheel

X

.1888

2.5 == .47

Adding this to the 15.104

Now,

pitch diameter of the wheel,

+ .47 = 15.57 mm. full diameter of the wheel. we have

figuring the pinion

= .236 1.888 + .236 = 2.12 mm. X

.1888

We

we have

1.25

full

may, however, figure the

work by adding teeth or leaves.

diameter of the pinion.

full

2.5 or 1.25 (addenda) to the

.1888

Circular pitch.

mm. 2.12 mm.

The

=

It will

the

difference

full

diameter of the wheel.

full

diameter of the pinion.

be noted that the definition for

somewhat

circular pitch reads rical pitch.

number of

For example

(80 4- 2.5) .1888 == 15.57

(10+1.25)

diameters with a lot less

is

like the definition for diamet:

circular pitch

is

the division

of the circumference of a circle (the pitch circle), whereas the diametrical pitch

is

(the pitch diameter). leaves

is

the division of the diameter of a circle

In both cases the number of teeth or

the divisor.

We must know the actual width of tooth and space in order to select a cutter to

make

a wheel. Herein

of calculating the circular pitch.

To

lies

the importance

attain this

use of the following formula: pitch diameter

X

3.1416

teeth or leaves

= one circular pitch

we make


:

:

A PRACTICAL COURSE IN HOROLOGY

38

Substituting the numerical values

X

15.1

3.1416

= .592 mm. circular pitch

80

The proportion of for the wheels

tooth or leaf to space

is

usually

one half of the circular pitch.

:

for the pinions, 10 leaves or less

:

one third of the circular

pitch,

for the pinions,

12 leaves or more

:

two

fifths

of the

circular pitch.

Now,

continuing with the above example to determine the

width of the tooth of the wheel and the leaf of the pinion,

we

find that

.592

= .296 mm., the width of the tooth, and

2 .592

= .197 mm., the width of the

leaf.

Problems 1,

What

2.

Define diametrical pitch.

2.

Calculate the diametrical pitch for the following:

the epicycloid? the hypocycloid?

is

center distance

7.5 millimeters,

—75 pinion — 10 leaves. wheel 4.

teeth,

Calculate the pitch

diameter for the above wheel and

pinion. Calculate the full diameters.

in

5.

Define circular pitch.

6.

Calculate the circular pitch, using the specifications given

Problem

J.


:

Tl

Part I

CHAPTER THREE

The Lever Escapement Time and experience have demonstrated of the lever escapement over timepieces.

become in

In

obsolete.

the

fact,

Since

all

several

other types for portable

other

types

introduction by

its

1750 the lever escapement has been the

experimentation and study. state of perfection

we

see

the superiority

have now

Thomas Mudge object of much

was developed into the today only after a number of

It finally it

unique and fantastic variations were tried and discarded.

Terminology The

several parts of the escapement are defined as follows

ESCAPE The escape wheel

is

WHEEL

that part of an escapement that delivers

impulse to the balance through the

Ratchet-tooth wheel:

the

medium

name given

of a pallet fork. to the English

type escape wheel, which has pointed teeth.

Club-tooth wheel:

that type of escape wheel

which has

a lifting face at the end of the teeth. Impulse face: the lifting

plane of a club-tooth wheel.

Locking face: the slanting face

of the teeth on which the pallets lock.

Toe: the intersection

of the locking face and the impulse face of a club tooth. 39


A PRACTICAL COURSE IN HOROLOGY

40

Heel: the intersection of the impulse face and the letting-off corner of a club tooth.

PALLET FORK The

fork

pallet

means of

pallet

that part of an escapement that,

is

jewels, receives impulse

by

from the escape

wheel and delivers impulse to the balance.

name given to the metal body to which is attached. The term includes the pallet jewels.

Pallets: lever

Lever:

the

a metal piece attached to the

impulse to the balance.

The fork

the

pallets that carries

occupies the extreme end

of the lever.

Fork

slot;

a notch cut into the fork for the reception of

the roller jewel.

Horns: fork •

the circular sides of the fork that lead to the

slot.

Receiving pallet

that pallet stone over which a tooth of

:

the escape wheel slides in order to enter between the pallet stones.

Discharging pallet

:

that pallet stone over

which a tooth

of the escape wheel slides in order to leave from between the pallets. Impulse face: the lifting plane of the pallet stone. Letting-off corner: the extreme end of the impulse face of a pallet stone

where the tooth of the escape wheel

Locking face: the face of a

pallet stone

lets

on which a tooth

ofiF.

locks.

ROLLER TABLE The jewel.

roller table

is

the circular disk that carries the roller


THE LEVER ESCAPEMENT Crescent:

41

a circular notch in the edge of the roller table

for the reception of the guard pin or fingeV.

a roller action comprising a single metal

Single roller: disk.

Double

roller

a roller action comprising two metal disks,

:

the larger disk carrying the roller jewel and a smaller disk in

which a crescent

is cut.

Roller jewel or jewel pin:

a flattened jewel that

is

inserted in the roller table.

BANKING PINS Banking pins are pins motion of the

that arrest or limit the angular

lever.

Equidistant, Circular and There are three types of lever

escapement:

the

S emit an gent al

pallet

Pallets

arrangements used in the

equidistant,

the circular

and the

semitangental.

Equidistant pallets.

In the equidistant the locking faces

of the pallets are an equal distance from the pallet center,

Figure

8.

Equidistant pallets.


A PRACTICAL COURSE IN HOROLOGY

42 as

shown

As

in Figure 8.

a result the lifting action on the

discharging pallet takes place too far from the point of tangency, necessitating the need for a greater lifting angle

on that stone.

Although the unlocking

favorable conditions, the lifting action in its distribution

its

performed under

is not,

being unequal

and unequal also as to the pressure of the

tooth on the pallets.

accuracy in

is

This escapement

calls for exceptional

construction.

c

f

Figure

Circular pallets.

9.

Circular pallets.

Circular pallets have the central portion

of the pallets' lifting faces an equal distance from the pallet center as

shown by the

lines

CA

half of the width of the pallets lines,

is

and

DA

in Figure 9.

One

placed on each side of these

which requires that the locking faces stand

at

an un-

equal distance from the pallet center, causing an unequal and increased unlocking resistance. is

more

lift

favorable.

Semitangental

mon

However, the action of

fault

in

pallets.

Setting on the locking

is

a com-

small wrist watches; hence a light lock

is


THE LEVER ESCAPEMENT

Figure essential to

10.

Semitangental

pallets.

With regard

good performance.

43

to this factor

the semitangental escapement, a development of recent years,

has found favor with

many manufacturers because

it

lessens

the resistance to unlocking, a natural fault with the circular,

and

at

the

equidistant. It will

same time minimizes the

be observed that the unlocking on the receiving pallet

EB

at the intersection of

slightly increased center distance results,

CA

is

The

of the

Figure 10 shows the semitangental escapement.

takes place on the tangent

A

lifting error

since the line

placed 31 degrees to the left of the center line

action of the discharging pallet

escapement with circular

pallets.

is

The

the unlocking and lifting actions are

CA.

BA.

similar to that of

an

designers claim that

more nearly equally

divided than any escapement that has yet been conceived.

Number Although nearly teeth

of Teeth in Escape all

Wheel

watches have an escape wheel of 15

we may make them

with

12, 14, 16, or practically

any


:

M

A PRACTICAL COURSE IN

HOROLOGY

number in this range. The first lever escapement as made by Thomas Mudge had an escape wheel of 20 teeth. The larger numbers result in a rather clumsy action and are Escapements using a wheel of

therefore not satisfactory.

12 or 14 teeth are used today in some wrist watches and have

For example, there

certain advantages.

between the

number of

pallet

arm and

is

more clearance

the escape wheel.

The

smaller

teeth permit the use of wider pallet jewels

and

a wider lifting plane for the teeth. Also the actual measure-

ment of 1^2 degrees of locking

is

greater because of the

increased distance between the locking comers of the pallets

and the

pallet center.

Wheel and The tions:

lever escapement has

is

two

distinct

and separate func-

(1) the action of the wheel and pallets and (2) that

These functions we

of the fork and roller. sider.

Pallet Action

The

first,

which has

divided into three actions.

to

shall

now

do with the wheel and

They

con-

pallets,

are

1 the locking

2 the draw 3 impulse or

The on a is

locking.

pallet

when

lift

The locking

Is

the overlapping of a tooth

the lever rests against the bank. This locking

necessary for the reason that

and another tooth

falls directly

opposite pallet, there

is

if

one tooth

lets of?

a pallet

on the impulse face of the

a recoil of the lever toward the

balance, causing a frictional contact between the guard pin

and

roller table.

stop the watch.

Contact in this manner would immediately

To

avoid this a certain amount of lock

Is


THE LEVER ESCAPEMENT However,

necessary.

should be as

it

as possible con-

with the proper safety in action.

sistent

The draw.

In portable timepieces the lock in

sufficient to insure safety in action.

an action whereby the is

little

45

effected

pallets are

It is

drawn

CA

slanting should be as

and

little

DA

into the wheel.

shown

as

not

necessary to create

by inclining the locking faces of the

right of the lines

itself is

This

pallets to the

in Figure 10.

This

as possible, yet enough to overcome

the friction of the tooth on the surface of the pallets, for it

can readily be seen that the combined action of lock and

draw makes a

resistance to the motion of the balance

and

has an important relationship to the position and isochronal rating of a watch. It

is

pallet

generally conceded that 12 degrees

is

However, because of the

satisfactory.

motion of the

draw on each

pallets the

draw

is

circular

changing continually, being

strongest on the receiving pallet at the point of unlocking,

whereas on the discharging

pallet

it

is

weakest

at the point

The nature of this action leads one to assume that a greater angle for draw should be given to the receiving pallet in fact, we find some authorities designing the escapement with 13 to 15 degrees draw on the receiving pallet. This would make the draw more nearly equal at the point

of unlocking.

;

of banking where

The

lift.

it is

most needed.

In well-designed escapements of the club-tooth

variety the actual

lift is

8^

degrees, being divided between

tooth and pallets in varying proportions.

Adding 1^^ degrees

for the lock, the total angular motion of the lever becomes

10 degrees.

Width

of pallet

and tooth.

It will

be observed that a


:

A PRACTICAL COURSE IN HOROLOGY

46

wide

a narrow tooth

pallet requires

;

likewise a

should be associated with a wide tooth kept to the minimum.

if

narrow

the drop*

pallet

to be

is

In this connection several pallet and

tooth combinations are listed below

CIRCULAR PALLETS TOOTH

PALLET

Width

Lift 1

6

2

5J4

degrees

7

degrees "

5

5"

654

6

"

^

4

5

"

•'

"

Width

Lift

3^

2J^ degrees "

354

"

4>^

"

3^ 4H

degrees "

Ay2

5^

"

"

EQUIDISTANT PALLETS 6

5

7

degrees "

7

degrees

5H 5^

6

Lift

Width

2y2 degrees

3 5^ degrees

Width

Lift

6

"

5M

"

"

"

3

"

3

Attention should be given to this fact pallets the lift

on the tooth should be

4^

"

than the Hft on the

Circular and equidistant pallets are not always

pallets.

However, there are exceptions,

interchangeable.

case of

"

in the equidistant

:

less

454

Number

1

and Number

5,

been interchanged by Grossman.

which are

Number

4

alike is

as in the

and have

suitable only

for circular pallets, especially so since the narrow pallets

perform the act of locking nearer as

shown

in

Figure

9.

to the lines

CA

and DA,

Numbers 5 and 6 would be

suitable

also for the semitangental escapement.

a term used to indicate the free motion of the escape wheel after one tooth lets off a pallet and another tooth locks on the opposite pallet. This factor is of more concern in practical benchwork and is treated fully in Part II, Chapter Six. *

Drop

is


THE LEVER ESCAPEMENT

47

The Fork and Roller Action The

relation

between

the fork and roller jewel as a mechanical action

may be

divided into two distinct and separate functions:

(1) the

Unlocking and impulse actions.

unlocking of the pallets and (2) the impulse to the balance.

One

action

is

the reverse of the other.

takes place as a result of

The unlocking

action

power derived from the balance

and spring, while the impulse to the balance receives

its

energy from the force delivered to the escape wheel by means In the unlocking action,

of the main spring and the train.

a short lever (roller- jewel radius) acts on a longer one (the lever fork).

A

must be associated

short roller-jewel radius

with a long lever which involves a large angle of contact as

shown by the angle

ABC

in

Figure

11.

On

the other hand,

a long roller- jewel radius must be associated with a short lever

which

the angle

results in

ABC

a small angle of contact as shown by

in Figure 12.

In other words, the shorter

the roller- jewel radius the larger

the angle of contact, and

is

the smaller the angle of contact the longer

is

the roller- jewel

radius.

A

4-to-l roller action.

In Figure 11 the relation of the

roller jewel to the fork slot is

4 to

1

;

that

is,

the lever

moves

10 degrees and the roller jewel remains in contact with the

The

fork slot for a space of 40 degrees.

action of unlocking

begins quite some distance from the line of centers because of the short roller-jewel radius.

jewel radius results in a

unlocking of the

A

much

However, a short

roller-

safer action and an easier

pallets.

3-to-l roller action.

In Figure 12 the relation of the

roller jewel to the fork slot is 3 to 1.

Although the unlocking


A PRACTICAL COURSE IN HOROLOGY

48

is

more

difficult,

energetic

when

it

action

roller jewel

the impulse to the balance

does occur.

with the fork

The 30-degree

slot is in

is

more

contact of the

accord with the theory

that the lever should be as highly detached as possible for finer results in timing.

Figure

11.

Fork and tion

The more radius

is

work we exact in

roller ac-

—single

delicate

roller.

Figure

12.

Fork and tion

roller ac-

—double

roller.

safety action of a long roller-jewel

not a problem in high-grade watches, for in such naturally expect a mechanical action that

its

function.

It follows, therefore, that

is

more

a long roller-

jewel radius which involves a small angle of contact

is

one


THE LEVER ESCAPEMENT

49

of the important factors to be considered in fine escapement

Of

design.

watches

A

course, in the cheaper

it is

wide

work and

in small wrist

not always practical.

The wide

roller jewel.

roller jewel results in

particularly satisfactory action of unlocking

a

by taking place

near the line of centers. However, the impulse to the balance is

not so favorable.

A

wide

roller jewel is inseparable

from

a long roller- jewel radius, for such a principle of design results in a very delicate action.

the safety action

A

narrow

much

A

wide

roller jewel

makes

less delicate.

roller jewel.

A wide

roller jewel, if associated

with a short roller- jewel radius, causes an unfavorable impulse to the balance too far from the line of centers,

and the

"uphill" circular path of the roller jewel along the side of

the fork slot during the impulse to the balance results in Also, on account of the greater angle

considerable friction. at

which the

roller jewel stands to the slot

when

the impulse

takes place, the drop of the fork against the jewel will to

more than

on the

its

shake in the

line of centers.

adapted for a short

slot, if

amount

measured when standing

Thus a narrow

roller jewel is better

and should always

roller- jewel radius,

be associated with a single-roller escapement. Single-roller escapement. In the single-roller escapement,

Figure

11,

it is

required that the roller table be as small as

possible to preserve the safety action.

Furthermore, friction

between the guard pin and the circumference of the table

was

would be considerably increased on a

larger than necessary.

motion of the lever to

less

It is difficult to

roller

table roller that

reduce the angular

than 10 degrees, and any relation

of fork to roller jewel less than a

3^

to

1 is

not practical.


V

A PRACTICAL COURSE IN HOROLOGY

so

Double-roller escapement.

'

We

have learned,' that

we

order to favor the impulse to the balance

ii^

require a long

and for the safety action a short radius.

roller-jewel radius,

the reason for the passing of the single-roller escape-

This

is

ment

in favor of the double-roller type, Figure 12, for in the

latter

type

The

we have two

rollers,

size of the safety roller is of

For the sake of soundness less

one for each action.

no great importance.

in action its radius

should not be

than one half the radius of the roller jewel. The smaller

the safety roller the sooner will the crescent approach the

guard

finger;

and,

likewise,

the

longer

the

roller-jewel

radius the later will the roller jewel enter the fork

slot.

It

follows, therefore, that the greater the difference between

the respective radii of the roller jewel and the safety roller the longer

must be the horns of the

roller jewel also plays

fork.

The width

of the

a part in the length of the horns, for

with any increase in the width of the jewel, the horns

may

be made proportionately shorter.

The

The

crescent.

circular notch in the roller

is

called

the crescent and should be wide and deep enough so that will be impossible for the it.

If

guard finger

to touch

made too wide, longer horns on

it

any part of

the fork would be

required to preserve the safety action.

The width is

of the crescent in the double-roller escapement

greater than in the single-roller type, for the reason that

the guard finger, due to

space to cover for in another

way

:

it

its

its

increased length, has a larger

safety action, or, stating the function

could be said that the velocity of the guard

finger has increased, whereas the velocity of the safety roller

has decreased.


THE LEVER ESCAPEMENT

51

Problems

as

1.

How

2.

Compare

3.

What

4.

Define draw.

differ

do the equidistant pallets

is

from the

the above with the semi-tangental escapement.

meant by locking?

How

does draw differ on the receiving pallet

compared with the draw on the discharging 5.

circular pallets?

How many

pallet ?

degrees are generally intended

for

the lifting

action ?

and

6.

Explain the difference between a 4 to

7.

Which

8.

Describe the single and double escapements.

of the above actions

is

1

preferred?

3 to 1 roller action.

Why? State the advan-

tages and disadvantages of each type. 9.

roller

10.

What

is

the

name

of the small roller that

escapement ?

What

is

the purpose of the crescent?

makes up the double-


Part I

CHAPTER FOUR

The

Controlling

The balance and of a watch and ism.

balance spring are the most vital parts

be properly called the controlling mechan-

Years ago the principal

rate time

difficulty in

was the temperature

unknown

balance was

much

may

Mechanism

maintaining accu-

error, since the

prior to 1769.

compensating

Often the error was as

as four or five minutes in twenty-four hours.

variation

is

due to three conditions

:

(1)

the expansion

The and

contraction of the metal in the balance, (2) changes in the length of the balance spring, and (3) variation of the elastic

force of the spring.

the spring

is

The

variation of the elastic force of

the most important factor; in fact, Ferdinand

Berthoud has estimated that 82 per cent of the error

is

due

to the variation of the elastic force.

Experimental demonstration.

A

simple experiment to

prove the correctness of the above statement

Figure

52

13.

may

be tried


;

THE CONTROLLING MECHANISM if

The

desired.

S3

materials needed are a sheet of brass about

4 or 5 inches long and 2 inches wide, a piece of brass wire,

and an old mainspring.

two

Drill

holes,

A

and B, Figure

13,

about yi inch apart and insert two brass pins and rivet Straighten the outer portion of the mainspring

securely.

and place the end between the

A

placed under pin

spring,

after

noticeably, as

The

Now, with

blowpipe heat the brass the

extreme end being

and over pin B, while the coiled portion

passes beyond the index C.

serve as a weight.

pins, the

coil

spring on the index.

will

the aid of an alcohol lamp and

plate.

It

becoming heated

may

beyond the index

will

be observed that

slightly,

has

deflected

be seen by noting the position of the

Upon

cooling

it

will return to its orig-

inal position.

Temperature Error of the Balance and Balance Spring The compensating balance. The compensating balance, or bimetallic balance, as

was designed

to

it

is

sometimes

called.

Figure 14,

overcome the errors resulting from the use

of the solid balance.

This balance

is

constructed by brazing

together brass and steel for the rim of the balance. brass

is

on the outside and constitutes about three

The

fifths

of

the total thickness.

Heat causes the metals

in the balance

assembly to expand

the arms become longer and, as the brass expands

more than

the steel, the loose ends of the rim curve inward toward the center.

Cold causes the loose ends to move outward away

from the clearly

center, while the

shown

in

Figure

15.

arms become It will

shorter.

This

is

be further observed that

the loose ends remain reasonably circular during temperature


A PRACTICAL COURSE IN HOROLOGY

54

Figure

14.

Compensating balance,

changes, but the radii of the curves change, their centers

O

for the normal temperature and

AA

for the high and low tempera-

being at the balance center shifting along the tures.

arms

However, the points BB, about 60 degrees from the

arms, remain at a fixed distance from the balance center, and it is

at these points that alterations for the

purpose of timing

should be made.

Middle-temperature error.

It is

evident from the above

analysis that

we can

manner

compensate for the expansion and contraction

as to

adjust the balance screws in such a

of the balance alone and maintain a constant This, however,

mean

diameter.

would not take care of the lengthening and

shortening of the balance spring nor for the changes in the


;

THE CONTROLLING MECHANISM

Figure

elastic force.

To compensate

on the spring,

it

is

55

15.

for the effects of temperature

necessary to add extra weight to the loose

ends of the rim. This results in a temperature error, between the extremes of heat and cold,

known

as the middle-tempera-

ture error due to the fact that the balance does not comforce and

pensate equally for changes in the elastic

changes in the length of the spring. sufficient

This

is

compensation (weights not moving

toward the center of the balance)

shown by

in

in the higher

for in-

near enough

temperatures

and too great a compensation (weights moving too far away

from the center)

in the lower temperatures.

The

result

is

a higher rate in the normal temperature, usually from two to six seconds in twenty-four hours, depending on the grade

of the watch.


A PRACTICAL COURSE IN HOROLOGY

56

Figure

This factor indicates the

is

clearly

uniform

shown

16.

in Figure 16.

To

by some means of compensating the

would be a constant mean

2ec

AB

exactly offset this rate error,

the opposite effect indicated by the line results

line

due to a rising tempera-

loss in the rate

ture on the balance spring only.

The

we must produce

CD. The

theoretical

rate along the line

EF.


THE CONTROLLING MECHANISM However, since the actual compensating alone

lies

to that

along the dotted line

shown

There

is

GH,

S7

effect of the balance

the actual rate

is

similar

in Figure 17.

no way of rectifying

this condition

except to use

a nickle-steel alloy called Invar, the perfection of which has

been realized only in recent years.

expands and contracts only a very temperature, and in using

it

the middle-temperature error Still

more

This remarkable metal little

instead of the ordinary steel is

considerably reduced.

recently another type of alloy

nickle-chromium, and tungsten and

Figure

18.

for changes in

known

Solid balance.

made

of iron,

as Elinvar has


A PRACTICAL COURSE IN HOROLOGY

58

been developed for the use of balance springs. Elinvar maintains

a constant

elasticity

and

is,

therefore, used in connec-

tion with a solid, single-metal balance as

The metal has and only

shown

in Figure 18.

the further advantages of being nonrusting

slightly subject to

no middle-temperature

magnetism.

Also there can be

error.

The Balance Spring There are two forms of balance springs in general use. These are the flat spring, Figure 19, and the Breguet, Figure 20.

The former has

the stud fixed to the

same plane as the

body of the spring, with the result that the vibrations take place in an eccentric manner. The latter, referred to as Breguet, has a portion of the outer coil raised above and

over the body of the spring.

The

original Breguet spring

was created by Abraham Louis Breguet (1747-1823), famous French horologist, but the spring by him bore no resemblance

Figure

\

19.

Flat balance spring.


THE CONTROLLING MECHANISM

59

-YA

Figure

20.

Overcoil balance spring.

to the theoretical terminals as applied to

The

modern watches.

we now find them are based on the foundadown by M. Phillips, French mining engineer, and

terminals as

tion laid

have placed the art of adjusting on a Theoretical terminals. corrected terminals

scientific basis.

The value of

lies in their

the theoretically

capacity to correct position

and isochronal errors by eliminating the eccentric wanderings of the center of gravity that are everpresent in the

The

flat

spring.

outer and inner terminals designed by L. Lossier perform

this function

very satisfactorily. These are shown in Figures

20 and 21. In the outer terminal, Figure 20, note that the overcoil

composed of portions of two

circles.

The outer

coil

is

tends


A PRACTICAL COURSE IN

60

HOROLOGY A

inward at

and forms an arc

of 180 degrees to B, which

is

planted at a point equal to .67 of the radius R.

The

overcoil

continues for another 83 degrees, the radius of

which

is

CO. To this must be added the amount necessary to reach through the stud. Figure 21 shows the Lossier inner terminal.

The elements

of the curve are the same as Figure

Theoretical inner terminal,

21.

clearly

shown

the

in the illustration.

applied to practically

all

corrected inner terminal

outer

terminal

Although the overcoil

is

not, its use being confined only

The reason no doubt

fact that the Lossier inner terminal is difficult to

harder to adjust and, unless the curve is

no

is

watches today, the theoretically

to the very finest watches.

it

and are

is

lies in

the

make and

100 per cent perfect,

better than a true terminal of the ordinary type.

Careful poising of the

collet is also necessary.

Problems 1.

Describe the compensating balance.

2.

What What

3.

is

type of balance springs are used with

balance wheels 4.

5. 6.

How What Draw

the middle-temperature error?

?

does the Breguet spring differ from the

flat

spring?

are the advantages of the theoretical terminals? a sketch showing the proportions of the theoretical

curves, both outside and inside.

\

solid, single-metal


PART

II

PRACTICAL REPAIRING


Part II

CHAPTER ONE Train Problems General

observations

in

gearing.

Attention

should

always be paid to the action of the outgoing tooth, noting that

up

its

its

point

is

not used and that the incoming tooth takes

load without drop.

The incoming

tooth should begin

pressing on the pinion leaf as near as possible to the line of centers, allowing for the fact that this

depending on the number of leaves

is

a varying quantity

in the pinion.

The

best

possible actions for pinions of ten, eight,

and six leaves are

shown

Figure

in Figures

1, 2,

and

3.

Note that

in

1

the action

begins on the line of centers, in

Figure 2 slightly before the

line

of centers, and in Figure 3 quite

some distance from the

line of

centers.

Gearing

may

be found defec-

tive with regard to several factors.

Below are

listed the

common. Pinion too large Pinion too small

Depthing too deep Figure

1.

Depthing too shallow

Ten-leaf pinion.

62

most


TRAIN PROBLEMS

Figure

Let us

2.

Eight-leaf pinion.

now examine

Pinion too large.

Figure

3.

63

Six-leaf pinion.

the errors in the order listed above.

Referring to Figure 4

it

will be ob-

served that the incoming tooth butts into the end of the pinion

Figure

4.

Pinion too large.

Figure

5.

Pinion too small.


A PRACTICAL COURSE IN HOROLOGY

64 leaf,

thereby stopping the watch.

If the error

is

slight the

action can be improved by enlarging the wheel, in which case

the outgoing tooth will propel

a

tooth.

Pinion too small. in a

leaf farther, resulting in

clearance between the incoming leaf and the in-

sufficient

coming

its

A

waste of power and

pinion too small, Figure

much

5,

results

noise, since the outgoing tooth

propels the leaf even to the point of slipping off before the

incoming tooth has started to press on a too small, the incoming tooth will leaf.

Wear

is

fall

leaf.

Hence,

Figure

6.

is

much

with a click on the

considerable and an error of this kind should

never be allowed to pass without correction. The larger pinion

if

fitting

of a

the only satisfactory solution.

Depthing too deep.

Depthing too deep.

Figure

7.

Depthing too shallow.

In a depthing too deep, Figure

the outgoing tooth continues

its

6,

action too long, most likely

with the point affected by excessive wear and a loss of power.


TRAIN PROBLEMS

A

Depthing too shallow. always unsatisfactory. Note propel

a

shallow depth, Figure

7,

is

that the outgoing tooth cannot

enough and the incoming tooth presses on

leaf far

its

65

In a very shallow depth a

leaf before the line of centers.

Enlarging the wheel some-

butting action usually results.

times puts the depth in a passable condition.

Worn

pinions.

If a

watch stops

with the slightest movement

and see

if

they are worn.

it is

Modern

and

in friction.

Wear

when

well designed gives

about 18 degrees

as a result quite

is

time will cause trouble.

in

starts

wrist watches frequently

service, but has the disadvantage of

engaging

and

well to look at the pinions

use a six-leaf escape pinion, which

good

in the train

pronounced

Often the fourth wheel can

be raised or lowered so that the wheel drives the pinion on the previously unused portion.

Repairing a Train The enlarging of

Stretching a train wheel. is

train wheels

a job that comes occasionally to the horologist,

for

it

happens that some watches are not right when they leave the factory.

It is,

of course, better to

are times, particularly

if

the watch

that enlarging the old wheel that

if

serve

the wheel

its

is

a

fit

is

new

not an expensive one,

permissible.

was imperfect

wheel, but there

The

to begin with

purpose and the watch runs

better,

fact

remains

and wx make

we

it

feel justified

in the act.

The

staking tool

preferred that

be used to stretch the wheel.

we work on

that the markings

when

may

the watch

is

made by

It is

the lower side of the wheel, so the

assembled.

flat

punch

We

first select

will not

be visible

a hole in the


A PRACTICAL COURSE IN HOROLOGY

66

die to loosely

fit

either the staff of the pinion or the entire

may

pinion as the case

The

require.

die is so adjusted that

the rim of the wheel comes under the punch.

frequently

It

happens that the part of the rim we wish to work on comes over, or partly over, another hole in the die.

happens

we may

This will hold a

select

a larger hole and plug

To

we

stretch a wheel

use a

this

with

pith.

while stretching the rim

staff in position

over a smooth and solid part of the

it

When

die.

flat- face

punch of such width

as to completely cover the rim including the teeth.

punch gently a succession of blows and the wheel slowly.

at the

Tap

the

same time turn

This stretches the rim satisfactorily and

with scarcely any visible punch marks, except where the arms are crossed.

To

keep the wheel as nearly round as possible,

sary to stretch the arms, as

we

it is

neces-

should not rely on the cutter

of the rounding-up tool to bring the wheel circular. Stretching of the arms

is

done separately

of the rim and teeth

—and

—

^that is,

after the enlarging

great care should be exercised

so as not to overdo the stretching.

The rounding-up we are ready to use

tool.

Having

finished the stretching

the rounding-up tool.

of the brass beds the diameter of which

First, select

is sufficient

one

to sup-

port the wheel and at the same time be perfectly free of the cutter.

Next,

tween the

select a cutter that exactly fits the space be-

teeth.

Occasionally,

we

find wheels the teeth of

which are too wide. In such cases a wider cutter is required in order to reduce the teeth to a width that will satisfactorily gear into the pinion. it

in the tool,

we

Having

center

it

selected the cutter

in line

and placed

with the guide, a knifelike


TRAIN PROBLEMS piece provided for the purpose of teeth will be cut perfectly upright.

up

is

now

making

67

certain that the

Tha wheel

to be rounded-

placed between centers and so adjusted that the

wheel turns freely and the rim barely touches the brass bed. Carefully advance the cutter so as to engage

See also that the guide on the cutter

wheel.

it

with the

is

properly

centered within the space preceding the one that the cutter

Cut the wheel but proceed

occupies.

carefully.

It is well to

try the wheel frequently in the watch so as to not overdo the correction.

Problems i.

How many

leaves are required of a pinion so that the action

begins on the line of centers 2.

Name

3.

If a train

4.

Why

5.

If

reason ?

?

four defects that are sometimes found in gearing.

is

is

noisy what

may

be the reason?

a shallow depth always unsatisfactory?

a watch stops frequently in the train,

what may be the


Part II

CHAPTER TWO Jeweling The

use of jewels as bearings for watches

question,

is,

without

one of the most important achievements to the Nicholas Facio, an

attainment of precision timekeeping.

residing in London, successfully applied jewels to

Italian

watches about the year 1704. The system used by Facio was not the same as employed in making the jeweled bearing of today. Instead of a hole piercing a jewel, a V-shaped depression

was ground

worked the

into the jewel.

The

into the depressed jewel in

present-day alarm

much

finally resulted in the

the

same way as

The Swiss were quick

clock.

realize the advantages of jeweling

which

was pointed and

pivot

in to

and began experiments

making of jewels as we

find

them today.

Bezel-Type Jeweling Jeweling of the bezel type

is

when

a rather difficult task

attempted by the usual hand methods. Yet the lathe attach-

ment intended for such work siderable

number of jewels

describe only the

is

practical only

are to be

hand method

set.

We

—a method

Few

tools are needed.

con-

shall, therefore,

which, after the

necessary experience, will satisfy the needs for purposes.

when a

all practical

These are a supply of

drills,

the usual gravers, a jewel graver, Figure 8, and a burnisher,

Figure

9.

68


JEWELING

69

Bottom

Side

Figure

Figure

The procedure

is

9.

Jewel graver.

8,

Jewel burnisher.

of four-millimeter brass wire.

and turn a small

Secure in the lathe a piece

as follows.

center.

Face

off the

end of the wire

Select a drill slightly smaller than

the jewel to be used and bore a hole about five millimeters deep. it

up.

With the jewel graver Next turn a seat to fit

enlarge the hole slightly to true the jewel.

The depth should be

sufficient so that the jewel will lie slightly

below the surface

of the wire. Next, cut a groove close to the opening for the jewel with a long, pointed graver. inserted but should

keep

it

from

first

falling out.

The

jewel

is

be moistened with a

Now

now little

rest the burnisher

to be oil

to

on the

T-rest; thrust the point of the burnisher in the groove,


A PRACTICAL COURSE IN HOROLOGY

70

Figure

Figure

10.

11.

Bezel type jewels.

forcing the brass against the jewel, thereby holding the jewel

A

in place.

may

jewel thus set

and the brass Figure 10

desired.

if

shows the work as described above. The dotted

show

the figure

the

the watch plate.

off.

perfectly secure

be faced off level to the jewel

clearly

fit

is

manner

End

which the

in

shake

is

setting

lines in

turned to

is

tried before the wire

This being satisfactory the wire

is

cut

is

cut

turned to

off,

the proper thickness, and stripped out with a sapphire jewel stripper or a highly polished graver.

by

sliding the setting

file

previously prepared with a

Three are is

face

is

polished

on an agate polishing stone or burnish

Number- 1

styles of bezel-type jewels are

shown

The

in Figure 11.

The method

buff.

used

in

watches and

for setting

all styles

the same.

Friction Jeweling Friction jeweling of watches

is

a simple and quick method

of inserting a jewel in a plate, bridge, or setting by means of friction.

Swiss manufacturers started using this system

1920, and since then

in

more and more manufacturers, both

Swiss and American, have adopted this method.


JEWELING In

fitting

a friction jewel, the

mine the depth the jewel This

shake.

made

is

procedure

is

to deter-

to be set to give the proper

end

accomplished by using a machine especially

for the purpose, of

the market.

is

first

71

which there are many

First, rest the

varieties

on

pusher on the broken jewel and

adjust the metric screw near the top of the machine so that the

new jewel may be

broken one had been.

forced in to the same depth as the

Second, push out the broken jewel

and ream out the hole with the smallest reamer that

away enough metal

will cut

to give to the plate a clean, straight hole.

Third, select the proper jewel, the outside diameter of which is

1/100 of a millimeter larger than the hole in the

Remove

plate.

the burr left by the reamer with the wheel counter-

sinks and push the jewel in place.

Replacing a friction jewel. watch that had a

To

friction jewel in

it

replace a jewel in a before,

it is

necessary

only to measure the size of the hole in the plate. This

may

be done by inserting the reamers or using a special gauge that

is

Having determined the the jewel required and push it in to the proper

available for the purpose.

hole size, select depth.

Figure

12.

Friction Jewels.


n

A PRACTICAL COURSE IN

HOROLOGY

Fitting jewel in removable setting. jewel in a setting that

may

If

we wish

to

fit

a

be removed from a plate, as in

the case of a balance or cap jewel,

we need

special tools to

hold the setting securely while reaming out the hole. There are various types of tools on the market

all

of which are

used in connection with the friction- jeweling machine. Several types of friction jewels are shown in Figure 12.

Problems 1. 2. 3. 4.

set?

What are the tools Name the styles of

How How

needed

in fitting bezel-type

jewels?

bezel-type jewels used in watches.

do friction-type jewels

differ

from bezel-type jewels?

do you determine the depth a friction-type jewel

is

to be


Part II

CHAPTER THREE

Making a Balance Many

Staff

horologists consider the making of a balance

a difficult task.

We

find

staff

workmen doing almost anything

a watch to avoid the necessity of making a bridges are bent up or down.

to

Balance

staff.

Unsightly graver marks are

found on plates and bridges. The balance arms are sometimes bent out of line in an attempt to permit the balance to clear the various parts, and pivots are often ground too short.

However, the making of a

man would go

staff is

not

difficult if

the repair-

about learning the art the same as with any

other performance requiring

skill.

No

one ever learned to

play a musical instrument in a few lessons or ever became

an expert engraver

in

a few months.

Preliminary Notes on Staff Making Gravers for turning

shown general

staffs.

Three gravers of the

in Figure 13 are needed for staff work. use,

suitable

also

for

B

staff prior to cutting

it

for

has a rounded point

for turning the cone portion of the cone pivot. is

is

square shoulders and the

cylindrical portion of cone pivots.

point flattened and

A

styles

C

has the

used for turning the lower end of the off.

73


A PRACTICAL COURSE IN HOROLOGY

74

ABC

Figure

13.

Gravers for turning balance

Sharpening the gravers.

seem it

Sharpening the gravers does not

to be given the attention

We

should.

staff.

by the average horologist that

have seen v^orkmen trying to cut a square

shoulder pivot with a graver having a point like a wire

Naturally their

work was

unsuccessful, yet these

nail.

workmen

did not reflect on the fact that possibly the graver was at fault.

The graver must have a sharp

point.

Even

the best

gravers cannot retain a keen edge very long while cutting

tempered

steel.

Therefore keep a sharpening stone handy and

make frequent use carborundum wheel

of

it.

Some workmen use an emory

to grind gravers.

done, as the point of the graver this point is the

is

most important

This should never be

frequently softened and

part.

Instead

we

use two

stones, a soft

Arkansas stone and a hard Arkansas

The

is

soft stone

for rapid cutting

or

and the hard stone

stone. is

for

the final finishing. After grinding the face, sHde the sides on

the stone so as to produce a

Making tice

flat

pivots for practice.

and smooth cutting surface.

The beginner should

prac-

making square shoulder and cone pivots before attempt-


MAKING A BALANCE STAFF ing the making of a

staff.

It will

75

be found that the larger

pieces of pivot wire are excellent for the purpose, as the

wire

is

hardened and tempered, ready for use. The length of

the cylindrical portion of a cone pivot

The

is

length of a square shoulder pivot

twice the diameter. is

three times the

diameter.

Measuring for the staff. Now, returning to our problem of making a staff, the first act is to take the necessary measurements, preferably from the watch, for the reason that the old staff

may

not be correct.

The well-known Boley gauge

serves the purpose very well,

since

reads both ways,

it

between the calipers and from the end of the the balance bridge lies

the

cap jewels.

flat

Make

securely pushed in place.

Figure

14,

with the lower certain

that

For the

measure from the

full

foot.

plate.

the

See that

Now remove

hole

jewels are

length of the staff A,

side of the lower hole jewel to

Figure

14.


A PRACTICAL COURSE IN HOROLOGY

76

The

the side of the upper hole jewel.

the roller table

B

is

height of the seat for

found by measuring the distance from th^

side of the lower hole jewel to the top of the lever, adding

enough for clearance and the thickness of the In like manner the distance for the balance seat

from the

roller table.

C is measured

side of the lower hole jewel to the top of the pallet

bridge, adding for the necessary clearance.

the upper end of the staft

D

is

The

length of

found by subtracting the

C from

length of the lower end to balance seat

the full

length A.

Preparing the is

Preparing the

steel.

next in order. Select a piece of

will

be a

finished.

little

steel,

steel

wire for the staff

the diameter of which

larger than the largest part of the staff

Heat over a gas flame

to a cherry red

place so as to see better the degree of heat, for

too bright, one

ruin

and plunge

This should be done in a rather dark

quickly into water.

is

when

if

the light

apt to overheat the steel and thereby

is

it.

The wire is now too hard to turn and we must therefore draw the temper. The wire must be made white in order to blue

it.

This

is

done

in the lathe

emory paper against the

The tempering

is

by holding a piece of

fine

wire.

done by drawing the wire through the

flame of an alcohol lamp; or, better

still,

lay the wire

on a

curved sheet of copper, keeping the wire rolling while being held above the lamp.

A

full

blue color

is

satisfactory for

staffs.

Turning the

staff.

Tighten the wire securely

in the lathe,

having extended the wire from the chuck sufHciently to include the full length of the staff and about

two millimeters


MAKING A BALANCE STAFF

Figure

With

additional.

15.

77

Pivot polisher.

hand graver turn the upper end

the

—

first

turning the balance seat to length from the end and almost

Next

to size, say .05 of a millimeter of the finished diameter.

turn the collet axis, followed by turning the remaining end nearly to the size of the hole in the roller table.

Turning a conical the pivot almost to

pivot.

size.

Turn

the cylindrical portion of

Next, using the graver with the

point slightly rounded, turn the cone, bringing

it

down

meet the cylindrical portion of the

is

followed

by cutting the slope between the

pivot.

collet axis

This

to

and the cone of

The turning of the upper end of the staff is now completed and we are ready for the pivot polisher and the

the pivot.

preparation of the grinding mediums.

The

pivot polisher.

very neat

little

The

pivot polisher, Figure 15,

instrument for grinding and polishing.

superiority of the instrument over any

questionable

;

it

hand method

is

is

a

The un-

does the work in a factory-like manner and

polishes the pivot

the pivot polisher

most is

beautifully.

It is to

not more generally used.

be regretted that


A PRACTICAL COURSE IN HOROLOGY

78

However, the successful use of the pivot polisher depends on the proper preparation of the laps and we

shall digress

moment to consider the method by which they are made how to keep them in good condition, and their varifor a

—

We

ous uses.

need laps of cast

and box-

iron, bell metal,

wood, and the material may be purchased from hardware stores

and material houses.

Cast-iron

and

bell

rial

may

and

bell-metal laps.

Laps made of

metal are used principally for grinding.

cast iron

The mate-

be purchased in rods of various diameters. For most

needs of the horologists, rods of about will suffice.

Having

^

selected the materail,

about ^2 inch long and bore a hole in

it

inch in diameter

saw

off a piece

of such size that a

reamer of the required taper may be used to enlarge the

The

hole

is

hole.

reamed out with a reamer of the same taper as

the taper chuck

shown

in

Figure

16.

The blank

is

placed in

Laps of various shapes are needed. Those most used are shown in

the taper chuck for turning with the slide rest.

Figure

17.

Figure

Figure

17.

16.

Taper chuck.

Laps for pivot

polisher.


:

MAKING A BALANCE STAFF Having turned the

and

laps, the face

79

must be

side

filed to

enable the lap to hold the grinding or polishing medium. Filing,

admitted, has a tendency to destroy

it is

this is

necessary in order to do good work.

shown

that

is

it

run practically

Number 4

possible to

File the lap

true.

or 5

The

so.

a lap

Experience has

many

by laying

truth, yet

times and face

it

still

down on a

Holding the lap between the thumb and

file.

along the cutting teeth of the

fingers, slide the lap

an inch or

file

its

lap should then be turned partly

and another stroke made. This crosses the

lines,

about

file

around

providing

a suitable surface for the embedding of the abrasive medium.

Next, prepare the side of the the lap on the lap.

file

This

lap.

is

done by drawing

in a direction parallel to the hole in the

Continue in this manner until the entire circumference

is filed.

Boxwood

polish on steel.

Boxwood laps are used for putting a high We may use the slide rest in turning the

boxwood

same manner as we did

cast-iron

of the

laps.

in the

and bell-metal

wood run

parallel

laps.

in preparing the

important that the grain

It is

with the hole in the lap so that the

end of the grain touches the work. The lap face only with a

Number

Now

ready, the preparation of the grinding

We proceed as

that the laps are

medium

is

next in

follows

Apply a small quantity of

oilstone

powder

to the first

partment of the three-compartment polishing block. little

watch

thin paste

oil

is

on the

file.

Preparing the grinding material. order.

is filed

and mix with a small knife or spatula

com-

Add

a

until a

produced. Place the pivot polisher on the lathe

and adjust the

lap spindle so that

from the bed

as the lathe spindle.

it

stands at the same height

Adjust the index

at the


A PRACTICAL COURSE IN HOROLOGY

80

base of the polisher to }i degree, so as to give the staff a slight taper

With

toward the end when the grinding takes

place.

the belting so fitted that the grinding surface of the lap

and the surface of the

staff rotate in opposite directions to

each other, feed the lap up to the work by means of the hard-

rubber knob at the rear. Apply thinly but evenly the oilstone paste to the lap and grind the balance seat.

grinding until the balance just

undercutting

is

fits

Continue the

the seat.

Be

sure the

deep enough so that the corner of the lap

does not touch the

staff.

be riveted true and

flat

If this

when

grind the collet axis to size

;

is

the case the balance can

the staff

is

Next,

finished.

after which, grind that portion

of the staff between the cone of the pivot and the collet seat.

Grinding and polishing a cone pivot.

Clean the work of

the grinding material with a piece of pith previously dipped in benzole

and hold

it

a dry piece of pith.

against the

staff.

For the cone

Finish cleaning with

pivot, the polisher is set

with the spindle at right angles to the pivot with the index set at

degree.

It is

further adjusted so that the center of the lap stands above the pivot as

shown

This

in Figure 18.

reduces the straight portion of the pivot perfectly cylindrical

and forms the cone time.

The shape

at the

same

of the cone

can be varied by raising or lowering the

spindle

of

the

polisher.

Instead of the cast-iron lap Figure

18.

Method of polishing

conical pivot.

we now

use a bell-metal lap

and a grinding medium of cro-


MAKING A BALANCE STAFF Reduce the

cus. fits

pivot, frequently trying the jewel until

Now

rather closely. place a

its

boxwood

diamantine and

oil

lap

remove the bell-metal lap and

and polish the

fit

it

in

pivot, using a paste of

previously prepared on the top section of

Continue the polishing

the polishing block. fits

81

until the pivot

the jewel freely.

The slope between the collet axis and the cone of the pivot may now be smoothed further by holding a jasper slip in the hand. It is then polished with a boxwood slip and diamantine.

Turning hub and roughing out lower end that the

upper end of the

staff is finished

the hand graver a long slope

lower end of the

With

stafif.

from the balance

seat to the

the pivot polisher set at the its

length, using

Smooth further with jasper with boxwood lap, diamantine, and oil.

powder and

and polish

Now

we next turn with

necessary angle, grind the slope for most of oilstone

of staff.

slip

oil.

Next, cut out roughly the lower part with a graver slightly flattened at the point.

the finished staff

Cut is,

is

off the staff

of course, a

and the

little

longer than

roller axis a little larger.

and measure the overall length. The

staff

Place the collet axis in a

split

little

chuck and stone

down

to be

Leave the hub a

too long.

off the

lower end until the

to the correct length.

Remove

staff is

worked

the staff and remeasure

the overall length between the calipers of the Boley gauge as

many

times as

is

required, taking only a

at a time so that the staff will not be

positively the

correct length.

little oflf

made too

short.

most exact method of bringing a

Any

the end

This

is

staff to the

other method, such as measuring back

from a predetermined amount of extra length and cutting off after the work is cemented, is likely to result in errors.


A PRACTICAL COURSE IN

82

Figure

HOROLOGY

Cement chuck.

19,

The cement chuck. The staff having been brought to the correct length we are now ready for the cement chuck. A screw brass tightly screwed turned in

it,

a chuck must have a center

deep enough to take the

cluding the hub. in place

in

up

staff

Figure 19 shows the center with the

and properly secured

lamp under the cement

that the brass will melt the

same time running the still

soft,

staff

cement and

insert the staff with the

Place a small

Heat

brass.

lathe slowly.

Again keeping the lathe

in-

in the cement.

Setting the staff in the cement chuck. alcohol

and

to

fill

sufficiently so

the center, at the

While the cement

thumb and

is

finger.

first

in motion, reheat the brass until

the cement adheres to the staff.

Holding the

staff in place

with a hollowed-out piece of pegwood resting on the

T

continue running the lathe until the cement

cooled.

Now,

true

up

is slightly

the staff while the cement

resting the pointed end of the

still

is

pegwood on the

bringing the pointed end against the roller axis.

must be placed staff in place

at

an angle so that we

may

T

while allowing the cement to cool.

soft

by

rest

and

T

rest

The

first

rest,

hold the

The

truing


MAKING A BALANCE STAFF follows immediately by holding the

and at a right angle to the

83

pegwood

front of

in

staff.

Turning the lower end of the staff. Turn the lower end of the staff, measuring from the end up to the roller seat, and bring the hub to the correct length. Reduce the roller axis to 0.1 of a millimeter of the correct diameter.

Set the pivot

polisher in position with the index adjusted to

^

degree

taper and grind the roller axis until the roller table slides

on and wedges

tight at a distance about

up

The

to the hub.

two

thirds the

way

pivot is next turned and polished as per

instructions already given.

The boiling

staff is

now removed from

the cement chuck. Fill the

pan or test tube with alcohol and

Finishing the ends of the pivots.

have not yet been finished but in the in

watch and

what manner

test for

it is

boil off cement.

The ends

well

first

of the pivots

to try the staff

end shake, so we may know better

to proceed.

Since the measurement for the

was made without allowance for end shake, it usually follows that a slight touching up of the ends of the pivots is

length

needed.

and

To

flatten

accomplish

this, place

the staff in a split chuck

each end slightly, using a hard Arkansas

slip.

Polish further with a jasper slip and finally finish with a

hardened

steel

burnisher and round the corners slightly.

COMMON

ERRORS IN STAFF MAKING

Beginners are very apt to overlook certain important details in the turning of is

a

staff.

One

of the most

common

the absence of a square shoulder for the roller seat, so

that the roller table will not

lie

flat

to the full diameter

of the hub. Undercutting for this purpose

is

not objection-


A PRACTICAL COURSE IN HOROLOGY

84

many watch

able, for

In

manner

like

factory staffs are

made

the balance wheel should

manner.

in this

the staff, that

fit

is,

the full diameter of the hub.

flat to

The

collet axis, the balance axis,

show a

and the

should

roller axis

definite taper so that the parts in question will

properly.

This

the instrument

fit

easily attained with the pivot polisher, for

is

may

be set to the desired taper.

In using

must be trained to recognize a

the hand graver, the eye suitable taper.

The

straight portion of the pivots should be cylindrical

and not tapering as we sometimes should be shaped

alike.

it.

the balance seat

also important.

Success will be realized

not as

difficult as

and likewise more

difficult

Satisfactory undercutting at the top of

to attain without

attention to detail,

and the cones

Again these conditions are made

possible with the pivot polisher

is

find them,

and

it

if

will

the beginner will pay strict

be found that

staff

some workmen would have you

making

is

believe.

Problems 1.

What

2.

How

3.

Explain in detail the hardening and tempering of the

staff 4.

gravers are needed in turning a staff?

do you measure for a

staff? steel for

making,

Name

the steps in turning the upper end of a staff in their

proper order. 5.

How do you

6.

Must

7.

Name

go about bringing the

staff to the

proper length ?

the staff run absolutely true in the cement chuck?

the points of particular importance in staff making.


Part II

CHAPTER FOUR

Pivoting Success drills

and

in pivoting

depends largely on the quality of the

in keeping the drills sharp.

pinions without tempering, yet there are times

ing must be resorted

to,

and

the

It is better to drill

when temper-

in such cases a small copper

wire shaped as shown in Figure 20

may

be used. The leaves

of the pinion are held in a pin vise or parallel pliers to prevent the heat

from spreading to that part while the copper

The end

heated over an alcohol lamp.

tempered to a blue

of the pinion

is is

color.

The pinion may be centered

in the split

chuck

true; otherwise, the cement chuck must be used.

if it

runs

Face

off

the pivot to the square shoulder and turn a small center. in a pin vise

and

a hole, which

Place the pivot

drill

should be a

deeper than the length of the average pivot.

Should the drill is

little

drill

it

immediately.

A

dull

apt to burnish the bottom of the hole, presenting a

serious problem. drill,

cease to cut, sharpen

drill

Should

which usually

this

happen, flatten the end of the

results in the drill cutting again.

The

hole having been drilled to a satisfactory depth, secure a piece of pivot wire in a pin vise, start

and hang

and

file

in the hole in the pinion.

exercised in filing the wire to

show 85

as

sufficiently to just

Caution should be

little

taper as possible.


86

A PRACTICAL COURSE IN HOROLOGY

Roll the wire as the filing takes place so as to leave the wire

round. Finish with the Arkansas

Next, force the wire

slip.

in the hole, cut off the wire with the cutting pliers,

the plug with a small

securely in the hole.

and tap

hammer, thereby forcing the plug

The

pivot

is

turned nearly to size with

the hand graver and finished to the proper size as already

III

I

I

I

I

I

I-T1 I

Figure

20.

Copper wire

in position for

I

I

I

II

umi

tempering pinion.


PIVOTING It is advisable to

explained.

undercut the square shoulder

slightly before polishing in order to

shown

in

87

keep the corner sharp as

Figure 21.

Figure

21.

Problems 1.

What

are the important points to

remember

a pinion

in drilling

for repi voting ? 2.

If

a

drill

ceases to cut what

may

be done so that the

drill will

cut again ? 3.

loose

What would be

the

when turning with

most Hkely reason for a pivot working

the graver ?


:

:

Part II

CHAPTER FIVE Fitting Balance Springs In fitting balance springs the

first

procedure

is

to deter-

mine the number of vibrations of the balance per minute. This

by

may

dividing the

first

the

be found in any watch

number of

number

with a second hand

of teeth in the fourth wheel

leaves in the escape pinion

number

ing the quotient by twice the wheel,

fitted

we have

ascertained the

;

then,

by

by multiply-

of teeth in the escape

number

of vibrations of the

balance per minute.

For example, the fourth wheel has 80 teeth; the escape pinion has 8 leaves

;

the escape wheel has

1

5 teeth.

80X30 = 300 vibrations of the balance per minute 8

Other examples are as follows

72X30 = 270 vibrations per minute 8

64X30 = 240 vibrations per minute 8 In watches where the seconds

we have

to

go back

fourth wheel

does not register

to the center wheel, as

the following examples

54

X

50

X 48 X

6X6X6

30

= 18,000 vibrations per hour 88

shown

in


FITTING BALANCE SPRINGS 64

X

X

66

60

X

30

8X8X6

89

= 19,800 vibrations per hour

Fitting a Flat Spring In

a

fitting

the proper

flat

spring to a watch,

This

size.

is

to the balance jewel as

radius

located

is

proximate strength,

necessary to

know

determined by centering the spring

shown

on the

inner regulator pin.

it is

first

we which may Next,

Figure 22.

in coil

The

correct

that stands inside the

desire to determine the ap-

be found by suspending the

balance and spring an inch or two above the bench. distance between the point where the spring

tweezers and the rim of the balance

is

is

If the

held by the

J^ inch, the spring

approximately of the strength

is

desired.

It

balance

is

large

or

small

if ;

the

the

remains practically the

distance

same.

does not matter

Of

course, this does not

necessarily decide that a particular spring is to be used, but

eliminate

all

it

does

unnecessary attempts

at vibrating a spring that is positively unsuited for a balance.

After trying several springs, finally selecting

to the above

cedure

is

one that conforms

test,

the next pro-

to vibrate the spring.

This can be done by counting the vibrations or by using an instru-

ment commonly known brator. r

Since nearly .

of recent years are

all

as a vi-

watches

J with a made '.1

Figure 22. Method for determining correct size of flat

^^^^^^

^^^-^^^


— A PRACTICAL COURSE IN HOROLOGY

90

300-beats-per-minute train,

it is

convenient to use the vibrator,

about which more will be written in the next paragraph. For the other trains

it

using a watch of

known

count the vibrations,

will be necessary to

The counting

accuracy.

is

done with

every vibration that takes place in a clockwise direction

;

that

The usual practice is to suspend the balance and spring by means of tweezers supported in the lathe bed. The lower pivot of the balance staff is,

the return vibration

is

not counted.

rests

on the watch

there

would be 150 counts for a 300-beat

Thus, counting for one minute

crystal.

135 counts

train,

for a 270-beat train, etc.

The

vibrator.

houses or

may

Vibrators

be

properly timed.

that

is,

in

make

his

own

old balance

may

material

and spring

be consulted

the

if

instrument.

of using the vibrator

is

that of comparison

watching the balance spring to be vibrated and the

and noting whether or not both vibrate

vibrator balance unison.

made from an

Material catalogs

horologist desires to

The method

may be purchased from

We

may

slide the

tweezers as

much

in

as a half a coil

toward the center of the spring or out a quarter of a

coil

toward the outside without altering the radius too much for a satisfactory fitting of the spring.

Having found a spring one quarter of a spring

is

coil

that vibrates properly, break

beyond the vibrating

point.

it

off

Next the

pinned in at the stud and the balance bridge with

balance and spring attached

is

placed in the watch for the

final timing.

Fitting the Breguet Spring

The of the

fitting

of the Breguet spring to a watch involves

work of

fitting

a

flat

all

spring, plus the forming of the


:

FITTING BALANCE SPRINGS

Figure

23.

The diameter need not be so exacting; however,

overcoil. it

91

should not be larger than one half of the diameter of the

balance, including half of the screws.

We

assume that the watch

shall

in

need of a new spring

ideally suited to the Lossier terminal

The procedure and break

is

as follows:

The

BC

and

AB

gives us the length of

We

BC.

2

CO X

3.14

360

X S3

this

we must

resort

desire to find the length of the

(Figure 23).

Number 1

BC =

flat

length of the active portion of the

to a bit of calculation.

portion

Figure 23.

two millimeters beyond the

must be determined and for

overcoil

in

Vibrate the spring in the

off the spring about

vibrating point.

shown

is

The

following formula


^

:

A PRACTICAL COURSE IN HOROLOGY

92

The

CO

radius

multiplied by 2 gives us the diameter of

that part of the overcoil concentric to O.

2

CO

turn

Hence the diameter

multiplied by 3.14 gives us the circumference, which in

divided by 360 to determine the length of

is

Multiplying the length of

now

degree.

degree by 83 degrees gives us

1

5C.

the length of

We

I

desire to

know

added to BC, gives us the

the length of

AB, which, when

total length of the curve.

Number 2:

AB =

(AO

+ OB) 3.14 2

Since

AO + OB

the circumference

equals the diameter and since one half of required,

is

it is

only necessary to multiply

AO + OB by 3.14 to give the circumference and divide by 2. Now,

taking a practical example,

diameter of the spring

is

.67

to the elements of the curve,

= 2.68 mm.

Substituting this value for

may

CO

Thus

of the radius.

CO = 4 X

us suppose that the

8 millimeters. The radius would be

4 millimeters. According is .67

let

CO

in equation

Number

1

we

determine the angular distance for BC.

BC =

X

5.36

3.14

X

83

= 3.88 mm.

360 Substituting again

length of

^= AB For the

for equation

Number 2 we

learn the

AB. (2.68 -^

4)3.14 + -^— = ^^^^ 10.48 mm. 2

full

millimeters.

length

we add

3.88 and 10.48, giving us 14.36


FITTING BALANCE SPRINGS

We

now grasp

93

the spring at the point intended for the

regulator pins and slide the spring along a scale in order to determine the actual length of the curve, allowing for sufficient extra length for the spring to is

make a

permissible to

slight

mark

reach the stud.

It

at this point to indicate

the starting point of the curve.

We

Raising the overcoil. overcoil.

This

are

now

ready to raise the

accomplished with rather heavy tweezers.

is

Grasp the spring with the tweezers about 25 degrees from

where the inward bend

that point tightly

and press

into a piece of

shown

takes on the shape

in

Hold

starts.

softwood

until the outer coil

Figure 24.

over and, measuring 22 degrees from the again until the outer

Figure 25.

Bring

takes the form

tweezers of

Figure 26.

coil lies level

Turn

the spring

first

bend, bend

wnth the body of the spring,

in the raised portion so that the overcoil

shown

many

the spring

in

To form

Figure 23.

shapes are desirable.

Alterations

should be

the overcoil,

These are shown

made

gradually,

in

being

careful not to bend the spring too much, for in so doing, the

Figure

Figure

25.

24.

First

First bend in forming overcoil.

and second bends

in

forming overcoil.


A PRACTICAL COURSE IN HOROLOGY

94

Figure

spring

is

liable to

26.

Balance spring tweezers.

be considerably weakened and possibly

broken.

The

Lossier curve

is

not adaptable to most small watches

for the reason that the curve central portion of the total

is

brought in nearer to the

mass than these watches

However, the above analysis may be used as a

permit.

will

basis

for calculating other forms, since the length of the curve

The forms more

does not vary very much.

adaptable to

present-day small watches are shown in Figures 27 and 28.

In Figure 27 note that the radius of the overcoil along the path of the regulator pins the spring. degrees.

The

Again

is

length of the curve in Figure

the regulator pins

is

is

180 degrees plus 20

28 the portion of the overcoil

at

placed in a position nearly in line with

the full radius of the spring.

takes the

three fourths of the radius of

form shown

In

this type, the

in the illustration

curve usually

and the bend for

the overcoil starts at a point opposite the regulator pins.

Converting a Flat Spring into a Breguet In order to obtain a closer position and isochronal rate in a watch originally fitted w4th a desirable to

make

flat

spring,

it

is

the spring over into a Breguet.

sometimes In

many


FITTING BALANCE SPRINGS

Figure 27.

Figure

28.

95


A PRACTICAL COURSE IN HOROLOGY

96

watches where there

is

room enough under

bridge this can be done without

a case of

suitable for

of

two

circles

Figure 29.

this

much

kind

the balance

The curve

difficulty.

composed of quadrants

is

connected by a straight line as shown in

The

radii of the circles

A

and

B

about one half of the radius of the spring.

are equal to

Owing

5

spiral nature of the spring the radius of the circle little

the outer coil of the the

The

longer than that of circle A.

same

coil after it

flat

spring and the solid line

was formed

into a Breguet.

shows the same spring with the removed.

A

realized.

The

dotted line

clearer picture of

only change to be

circles

its

Figure

29.

a

CC

shows

DD

shows

Figure 30 lines

form

thus

to the

shorten the regulator pins and raise the stud.

c \

is

and dotted

relative

made

to the

is

watch

is

The curve

to is


:

FITTING BALANCE SPRINGS

Figure theoretically correct to be equal to

and

if

any type of

97

30.

properly executed

it

will be

found

overcoil.

Eccentric Motion of the Spring After a spring has been vibration coil.

may

The

fitted

to

a watch an eccentric

be observed due to a faulty form of the over-

rules for correcting the eccentric

motion are as

follows 1.

If the eccentric motion takes place opposite the regula-

tor pins (as in

a

flat

spring), bring in part of the overcoil

toward the center of the spring. 2.

If the eccentric motion takes place on the

the regulator pins,

main body of the

move

same

side as

part of the overcoil hack into the

spring.

Truing Balance Springs The attainment

of successful balance-spring truing comes

only with continued practice and patience.

It is

one of those


A PRACTICAL COURSE IN HOROLOGY

98

are

accomplishments that

For

printed page.

difficult

this reason

we

through the

teach

to shall

make

only a few

general statements as to the manipulative operations.

In truing the round spring beyond the that the spring to be out as

is

never necessary to manipulate the

it is

first

quarter of the inner

shows a spring divided into quarters.

point.

The

assuming

true except for that portion which

a result of pinning in at the

referred to as

coil,

first

spring

and the procedure

collet.

The

quarter, half, third quarter,

may

is

likely

Figure 31

sections

are

and pinning

be wide at or near any of these points

in truing consists of

the spring in the desired directon.

The

pushing or twisting

dotted lines in Figure

32 show the manipulating required to bring the spring true in the round.

2

Figure

31.


FITTING BALANCE SPRINGS

Figure

Dotted

32.

lines indicate

manner

in

99

which the balance spring

is

twisted to true in the round.

In truing the

flat

the spring

is

pushed down or raised up

at those points that are high or low.

Problems 1.

Give the formula for determining the number of beats per

minute of a watch. 2.

How

do you determine the correct

size of a flat spring for

a

given watch ? 3.

How

4.

What

do you determine the correct is

6.

How do you go about How do you correct

is

the

How same

if

the

6.5 millimeters ?

forming the overcoil ? an eccentric motion of the spring that

takes place opposite the regulator pins 7.

Breguet spring?

the correct length of a Lossier outer curve

diameter of the balance spring 5.

size of a

?

do you correct an eccentric motion that takes place on

side as the pins ?


Part II

CHAPTER

SIX

Escapement Adjusting In this study of the

we

lever escapement

concerned with practical benchwork

that

;

are particularly

is,

good order the escapement of a given watch.

the placing in It is

important,

however, that we have some understanding of the theoretical principles involved

much

and

shall

w^e

indulge, therefore, in as

theory and escapement design as

is

necessary to aid

in the execution of practical repair problems.

The importance of understanding be

overestimated.

the escapement cannot

Large pocket watches often

function

quite satisfactorily with faulty escapements but with small

wrist watches ladies'

it is

very different.

The escapement

watches must be practically perfect.

in small

Since the larger

per cent of the watches that are brought in for repair today are wrist watches there

work.

is

need for greater

skill in

escapement

Inadequate knowledge results only in an endless

amount of trouble with watches perhaps only occasionally.

that stop persistently, though

Erratic rates, too, can be traced

to defective escapements,

Wheel and The

best

escapement

way is

Pallet Action

to obtain a practical understanding of the

to proceed step

by

100

step,

studying the separate


ESCAPEMENT ADJUSTING functions, after

be analyzed.

101

which the escapement action as a whole

Our

will

attention will first be directed to the prob-

lem of banking the escapement to the drop.

Banking means that

The term "banked

to the drop.

to the drop"

the banking pins are turned in such a position

that a tooth of the escape wheel will slide past the letting-off

corner of a

pallet,

thereby permitting the lever to reach the

opposite banking pin.

In order to effect a banked-to-the-drop condition, first

necessary to turn in both banking pins.

face of one pallet will

now show

contact with the impulse

owing

that the banking pins have been turned

the tooth

in,

to pass the letting-off corner of the pallet.

to the fact is

unable

Let us assume that

the impulse faces of the receiving pallet and a tooth

Turn the banking away from the line

rests,

pin, against

of centers slowly until a tooth

instant another tooth will lock pallet.

At

this

on the locking face of the

dis-

Next, move the lever to the opposite banking

pin, resulting in a contact being

shown between the impulse

Turn

the banking

away from

the line of

faces of the discharging pallet and a tooth. pin, against

show

which the lever now

passes the letting-off corner of the receiving pallet.

charging

is

The impulse

face of a tooth of the escape wheel, but

contact.

it

which the lever

rests,

centers until the tooth drops as already explained, and the

job of banking to the drop

is

completed.

DROP LOCK The

extent of the lock on the pallets after an escapement

has been banked to the drop

is

called

drop

lock.

This lock

takes place the instant a tooth drops on the locking face

of a pallet.


A PRACTICAL COURSE IN HOROLOGY

102

In Swiss watches and some American wrist watches

it is

not practical to bank the escapement to the drop because of the fact that the banking pins are not supplied with eccentric

In this case the usual practice

screws.

lever until the escape tooth drops

cease

moving the

A

and

to slowly

same

at the

slight additional

the

instant

motion of the lever

should be required before the lever will reach is,

of course, beyond that of drop lock.

is

called slide

and

move

and take note of the extent of the

lever

lock on the pallets.

is

The

will be considered

its

bank, which

additional motion

further in the later

portion of this chapter.

Drop

Correct drop lock.

lock

pending on the position of the arm, but

it

pallet

stones in the pallet

should be as light as possible consistent with

A

proper safety in action. the

a varying quantity, de-

is

drop lock of 1^^ or 2 degrees

is

amount usually adopted for pocket watches, whereas 2 or

3 degrees

is

allowed for wrist watches.

Altering the drop locks.

If the

drop locks are too light

or unsafe, a deeper lock can be had by moving out one or

both

pallets.

Likewise

lock can be had by

be observed that

on both

pallets

if

the drop locks are too deep a lighter

moving

when one

and any

in

one or both

pallet is

moved

pallets.

the lock

is

It will

changed

alteration of the pallets should always

be followed by rebanking to the drop.

Out on

of angle.

The

lever should

either side of the line of centers.

move an If the

is

equal distance

If the lever does not

said to be "out of angle."

drop locks are deep, out of angle can be corrected by

moving motion

equal distance the lever

move an

in the pallet is

shorter

on the side where the

from the

line of centers.

lever's

If the

angular

drop locks


— ESCAPEMENT ADJUSTING are light, out of angle can be corrected by

on the side where the

pallet

from the

If the

line of centers.

out of angle

(if slight)

lever's angular

103

moving out the motion

can be corrected by carefully bending staff.

This can be

done by holding the lever with a small pair of it

longer

drop locks are satisfactory,

the lever as close as possible to the pallet

bending

is

with the thumb and

first finger.

pliers

and

And remember

rebank the escapement to the drop after each alteration.

THE DRAW The

force that keeps the lever against

"draw."

It exists

its

bank

called

because of the inclination or slant of the

locking face and the shape of the tooth.

pallet's

is

It will

be

observed in Figure 36 that the receiving pallet inclines in the

toward the

direction

center, thus

degrees

is

and the discharging

pallet

away from the pallet draw. A draw of 12

the same direction but

in

inclines

pallet center

forming the angle for

considered sufficient by most horologists.

Examining the draw. Take a watch oiler or similar small tool and lift the lever away from its bank, but not far enough to cause the

and

escapement to unlock.

in so doing the lever will, if the

against the its

its

escapement

is correct,

bank.

bank.

The purpose of draw

is

to avoid unnecessary friction be-

tween the guard pin and the receives a jolt the lever

the guard pin action of

Draw to its

release the lever,

Try this again with the lever opposite banking. The lever should at once return

return immediately to

to

Now

comes

is

roller table.

When

thrown away from

its

the watch

bank and

in contact with the roller table, but the

draw causes the

lever to return at once to

its

bank.

should be sufficient to effect the return of the lever

bank for

all

ordinary conditions. If the draw

is

exces-


A PRACTICAL COURSE IN HOROLOGY

104

sive, there will

be an unnecessary recoil of the escape wheel,

causing a condition whereby too balance and spring

is

much

of the force of the

used in unlocking the escapement. The

waste of power and a shorter arc of motion of

result is a

the balance.

Altering the draw.

As

a rule want of draw

In most cases the jewel

sufficient angle of a pallet stone.

be tilted in the pallet arm. If the jewel

may

jewel

the jewel

be substituted or the

more

due to

is

slot

fits tightly,

in-

may

a thinner

may be widened

to give

angle.

THE DROP Drop

the time a pallet

defined as the free motion of the escape wheel at

is

when one

tooth passes the letting-off corner of

and another tooth comes

face of the opposite pallet.

in contact

Drop may be

with the locking

also defined as the

distance a tooth of the escape wheel travels without doing

any work.

Examining the drop.

With

a tooth locked on the re-

ceiving pallet observe the space that separates the letting-off

corner of the discharging pallet from the heel of the tooth.

Now move

the lever to the opposite banking pin, thereby

causing a tooth to lock on the discharging

Next ob-

pallet.

serve the space that separates the letting-off corner of the

from the heel of the

receiving pallet

Of find

course, the drop should be equal, but

it

so.

A

These errors

close inside, tip one or both pallets If close outside, tip

pallet staff.

not always is

and a small drop on the discharging

called "close inside."

stafif.

we do

small drop on the receiving pallet

"close outside," is

tooth.

call

called pallet

for correction.

away from

If

the pallet

one or both pallets toward the


ESCAPEMENT ADJUSTING moving one

Usually,

question

may

105

arise as to

which

move. This would

pallet to

depend largely on the condition of the draw, the drop

and the angular motion of the lever from the for

we

shall

any reason

soon learn that whenever a

all

The

pallet is all that is necessary.

line

locks,

of centers,

pallet is shifted for

of the above conditions are altered.

SHAKE Shake

is

defined as that space separating the letting-ofif

corner of the pallet from the heel of a tooth opposite pallet is

is

when

occurs at the time

the tooth

will be

is

for shake

locked at the lowest

When moving

locking corner of the pallet. its

the

locked at the lowest locking corner. Shake

similar to drop except that the examination

from

when

the lever

away

bank but not enough to unlock the escapement,

it

observed that a slight recoil of the escape wheel has

taken place. This action lessens the space between the lettingoff corner of the pallet

that shake

is

always

less

and the heel of the

tooth,

showing

than drop. If an escapement has no

shake the watch will stop.

THE LIFT Modern escapements have a total lift amount of lift separately on tooth and varying proportions in a club-tooth

requires

escapement

considerable

noticed that the

both

in different

pallets.

On

lift

is

of 83^ degrees.

pallet is designed in

makes of watches. The

lift

a very complicated action and

study to understand

it.

It

will

be

does not function exactly the same on

the receiving pallet the wheel

also does the pallet

The

and the

pallet's locking

greater velocity than the letting-off comer.

ing pallet the condition

is

moves up

as

corner moves with

On

the discharg-

reversed and the wheel moves


A PRACTICAL COURSE IN HOROLOGY

106

Figure

Figure

down

33.

34.

Lift

on receiving pallet

Lift on discharging pallet.

while the pallet moves up. Also, the letting-off

of the discharging pallet

moves with greater

comer

velocity than

the locking corner.

A

good action between the wheel and

pallets is

shown

in

Figures 33 and 34. Note that as the tooth leaves the locking faces of the pallets, the toe of the tooth

shows contact only

with the pallet's impulse faces. Contact in this manner continues

completely across the pallets until finally the two

impulse faces meet nearly parallel, and after that the heel


ESCAPEMENT ADJUSTING

Figure

Curved

35.

pallet stones

107

by A. Lange

&

Son.

of the tooth passes the letting-off corner of the pallets.

comes

heel of the tooth pallet

on the discharging

into action quicker

move

also there is a tendency for the tooth to

;

The faster

along that portion of the lifting plane near the letting-off

The

corner. that

is,

To

opposite takes place on the receiving pallet;

the action

is

faster at the start of the

obviate this difficulty, A.

lift.

Lange and Sons some years

ago made watches with escapements so designed that the receiving pallet had a convex lifting face, the discharging pallet

a concave lifting face, and the lifting faces on the teeth

were also curved (Figure 35). This system, served,

would cause the

tion at a

Loss lift

lift.

There

on the discharging

This

is

shown

in

from each

is

a definite amount of loss of

pallet of the club-tooth escapement.

Figure 36.

other.

be ob-

velocity.

5C

escape wheel describes the circle deviate

will

lifting action of the tooth to func-

more nearly constant in the

it

a straight line but the

is

DD

;

hence these lines must

In order that 5^^ degrees of lifting

take place, a lifting angle of

6%

degrees

discharging pallet. However, this loss of

is

required of the

lift is

a problem to

be reckoned with principally in the equidistant the circular pallets the loss of

lift is

very

little

pallets.

In

for the reason


108

A PRACTICAL COURSE IN HOROLOGY

p<

c a CO

•3


ESCAPEMENT ADJUSTING

109

CO

u CO


;

A PRACTICAL COURSE IN HOROLOGY

no

mid-way between the locking

that the tangents are planted

and of

(Figure 37). The loss

letting-oif corners of the pallets

lift

in the semitangental

escapement

also small, usually

is

amounting to about one-half degree (Figure 40).

The Fork and Roller Action In this study of the lever escapement

we have up

till

now

concerned ourselves with such factors as banking to the drop

drop lock, draw, drop, shake, and the it is

We

lifting action.

These,

observed, constitute the escape wheel and pallet action.

now

are

which

is

ready to investigate the fork and roller action

quite a study in itself.

There

is,

however, a definite

relationship between the

two actions and the

cannot

studied

be

successfully

Hence

account of the former. in its entirety

was outlined

escapement

in satisfactory

The

is

this to a

lift

the wheel and pallet action

first

1^

and

it is

assumed that our

adjustment up to this point.

on the tooth and

drop lock of

mentioned

without taking particular

We

have stated that the

pallets is

S}^ degrees. Adding

lever's angular motion.

combined

last

degrees, the total angular motion

of the lever becomes 10 degrees.

The

of 10 degrees should be

is

all

that

lever's angular

motion

necessary for the roller

jewel to pass in and out of the fork satisfactorily without catching.

Now,

placing the balance in the watch,

ready to try the

tests

guard safety

and the corner safety

eyeglass in

test

making the

for the safety locks.

tests,

we proceed

test.

we

are

These are the

Using a strong

as follows.

SAFETY LOCK TESTS Guard safety

test.

Rotate the balance so that the roller

jewel stands outside of the fork and with the

first

finger


ESCAPEMENT ADJUSTING

Figure

3S.

Guard safety

hold the balance in this position. similar small tool,

lift

the lever

111

test

Now, with a watch oiler or away from its bank, thereby

causing the guard finger to come in contact with the edge of the safety roller as shown in Figure 38.

With

the lever

held in this position examine the remaining lock on the pallet.

This remaining lock

is

called a safety lock

and

it

should


A PRACTICAL COURSE IN HOROLOGY

112

represent one half of drop lock or }i

The

degree of lock.

should next

test

be tried on the opposite pallet and a similar lock should be found.

Corner safety

test.

Starting with

the roller jewel in the fork

rotate

slot,

the balance slowly until such time that

one tooth passes the

letting-off corner

of a pallet and another tooth comes in contact with the locking face of the

opposite

A

pallet.

motion applied

additional

slight

to the balance will bring

the roller jewel in a position opposite

With

to the slot corner.

held in this position,

from

Figure 39. Corner safety test. roller jewel as

its

lift

the balance

the lever

away

bank, thereby causing the

slot

corner to come in contact with the

shown

in

examine the remaining or safety opposite pallet and

if

With the lever held thus, lock. Try this test on the

Figure 39.

the safety lock

pallets the lever's angular

is

the

motion from the

same on both

line of centers is

practically equal.

The

shown by the comer test should be the same as the safety lock shown by the guard test that is, the safety locks from both sources should show }i degree of safety lock

;

Note Although this always work out in practice.

lock.

corner test test

that

freedom

is less

is, if

correct in theory

If the safety lock

on

it

does not

shown by the

than the safety lock shown by the guard

the corner freedom

—no harm

pallets is safe

is

results,

all

is

greater than the guard

provided that the locking of both

of the teeth of the escape wheel.

How-


ESCAPEMENT ADJUSTING ever, if the corner

the roller jewel

is

fork, causing the

freedom

is less

113

than the guard freedom,

apt to catch on the tips of the horns of the

watch

to stop.

The curve test. To test an escapement for the error stated above, we use what is called the curve test. To apply this test

is

it

necessary to rotate the balance so that the roller

jewel stands completely past the horns of the fork. Next, the lever finger to

the lever will

away from its bank, thereby causing come in contact with the safety roller is

lift

the guard

and, while

held thus, turn the balance so that the roller jewel

move toward

the fork

slot.

horns of the fork and enters the factory as far as this test

is

If the roller jewel passes the slot,

concerned.

catches on the tips of the horns, a tions could be present.

the escapement

is satis-

If the roller jewel

number of

The most common

faulty condi-

are: guard finger

too short, roller jewel advanced too far, or lever too long.

The drop

locks being correct,

it

is

now

apparent that the

guard, corner, and curve tests aid in determining the correct length of the lever.

work

It

is

to lengthen the lever

common

practice in escapement

by stretching

it

or to shorten

by grinding the horns as the case may require.

mind

that the condition of the drop locks

is

So bear

first

it

in

taken ac-

count of and the fork and roller action afterward.

Slide

Up

to this point in our discussion, the escapement has

been banked to the drop.

The

subject of slide

is

next in

order.

The opening

of the banking pins beyond that of drop

lock

called slide.

Slide should be large

is

freedom for escaping; usually }^ degree cient.

Any amount more

enough to permit

is

considered

suffi-

than this only increases the angular


:

A PRACTICAL COURSE IN HOROLOGY

114

motion of the lever and

its

connection with the balance,

resulting in an increased unlocking resistance, a shorter arc

of motion of the balance, and poor timekeeping. pins should be placed as far as possible

The banking

away from

the pallet

center so as to lessen the strain on the lever pivots should

the escapement overbank. Slide

is

the last adjustment, the finishing touches, so to

speak, in escapement adjusting.

The As let

sort of

Theoretically Correct Escapement

summary

of our discussion of the escapement,

us consider the specifications of a correctly designed

escapement.

When

banked

as follows

Drop

lock

to the drop, the specifications should read


ESCAPEMENT ADJUSTING

115

1 a

s «>

c bo

it

4>


A PRACTICAL COURSE IN HOROLOGY

116

purpose the semitangental escapement shown

for this

Figure 40, as

comprises the best and

it

latest

in

design in

escapement construction.

The

materials needed for drawing are

drawing instruments,

pencil,

drawing paper, and India

large

ink.

and a French curve would be

a drawing board,

:

and small protractors,

AT

two

square,

triangles,

desirable although not absolutely-

necessary.

Study the drawing thoroughly before

what points the various angles also, to

make

starting.

originate.

It is

Note

at

important,

the drawing on a large scale so as to minimize

the errors arising from imperfections in our drawing instru-

ments.

who have no knowledge

Students

of mechanical

drawing would do well to read several chapters

in

any good

textbook on mechanical drawing.

Recommended texts: Roberts, William E., Beginning Mechanical Drawing.

Manual Arts

The

Press, Peoria, Illinois, 1943.

Bennett, Charles A., Beginning Problems in Mechanical

Drawing. The Manual Arts Press, Peoria,

Illinois,

1934.

Practical Application of Escapement Tests

Knowledge of

the several escapement tests will be of

value unless they reveal the necessary corrections to be in defective escapements.

therefore, to

show

The purpose

made

of this section

is,

the application of the several tests as a

guide to escapement alterations. in the following

little

All of the examples listed

pages are based on actual problems experi-

enced and corrected by the writer in the course of practical

work

at the bench.


ESCAPEMENT ADJUSTING In

all

cases

is

it

first

117

assumed that the escapement was

banked to the drop.

Adjustment

1.

— correct Guard freedom — excessive Corner freedom —

Drop

locks

correct

In this escapement the guard freedom was greater than the

When

corner freedom.

the curve test

was

jewel would catch on the horns of the fork.

tried the roller

The

correction

consisted of flattening the end of the guard finger.

For

this

purpose a punch should be ground so that the end will

A

in the fork slot.

do the work. In some cases the guard pin

by forcing

it

hammer

very light tap with a small

may

fit

will

be lengthened

further through the piece in which the pin

is

In this case, however, the pin could not be length-

placed.

ened, and, besides, the crescent in the safety roller

was

rather wide. After flattening the guard finger the sides were-

stoned to provide the necessary guard freedom. safety tried

test,

and

the

all

comer

tests

The guard

safety test, and the curve test

were found

satisfactory.

were

The banking

pins were opened for slide.

Adjustment

2.

— correct Guard freedom — excessive Corner freedmn — excessive

Drop

When pallets

lock

the guard test and the

comer

would recede from the tooth

test

to such

were

tried the

an extent that

the impulse faces of both tooth and pallets would

show


A PRACTICAL COURSE IN HOROLOGY

118

the safety locks did not function on

some

contact; that

is,

of the teeth.

Since the drop locks were correct the excessive

guard and corner freedom suggested that the error was that

The

of a short fork.

guard

and corner

test

lever test

was therefore stretched and the

were again

be well

It will

tried.

to state at this time that the stretching should be done a verylittle

at

a time, frequently making use of the

stretch a lever, place a small, flat- faced tool

it

sides

becomes bent

If the lever

during the act of stretching, turn it

in the staking

Using a punch with

and lay the lever thereon.

flattened, lightly tap the lever.

give

stump

To

tests.

over on the stump and

another very light tap, using the same punch. Having

found the guard and corner

tests satisfactory after stretching

the lever, the banking pins are opened for slide.

Adjustment

3.

â&#x20AC;&#x201D;

Drop locks deep Guard freedom satisfactory

â&#x20AC;&#x201D; Corner freedom â&#x20AC;&#x201D; satisfactory

Since the drop locks were deep, the

first act

was

to

move

It

was found

after rebanking to the drop that the roller jewel

would not

in both pallet stones

and rebank to the drop.

The

pass in and out of the fork. position a

little

nearer to the balance

balance, the corner test

was found

to

was

from the

tried

staflf.

was

reset in a

Replacing the

and the comer freedom

be correct, but when trying the guard

guard freedom was found.

ment of the

roller jewel

The guard

the curve test were tried and

no

This example being an escape-

single roller type, the

roller table.

test

all

guard pin was bent away test,

the

were found

which the banking pins were opened for

comer

test,

and

satisfactory, after

slide.


ESCAPEMENT ADJUSTING Adjustment

119

4.

light Drop locks none Guard freedom

— Corner freedom — faulty

Since the drop locks were light the

This made

the drop lock.

pins to a

it

first act

was to increase

necessary to spread the banking

new banked-to-the-drop

A

position.

proper guard

freedom and safety lock were found when trying the guard but

test

found

when

was

the corner test

tried the

and the locking was not safe on

to be excessive

Examination showed that the

of the teeth.

tipped slightly toward the

staff.

The

in a position parallel with the staff

As

a

tests

were

slide

was added.

final

and

tried

was

and the corner

all

jewel

roller

roller jewel

again tried, this time showing the correct safety lock.

freedom was

test

reset

was

comer freedom and

check-up, the guard, comer, and curve

all

were found

satisfactory, after

which

Adjustment 5. Drop locks

— deep

Out of angle

When

banked to the drop the escapement showed too much

guard freedom on the side of the receiving tically correct

To

pallet

and prac-

freedom on the side of the discharging

correct the deep lock

and

to equalize the angular

pallet.

motion

of the lever from the line of centers, the discharging pallet

was moved

in.

The escapement was again banked

and the guard and corner

tests

were

tried,

to the

drop

showing too much

guard and corner freedom, also a complete absence of safety lock.

The drop

was assumed

locks were considered passable, so the error

to be that of a short fork.

The

lever w^as


A PRACTICAL COURSE IN

120

HOROLOGY

stretched and the guard and corner tests were tried, showing satisfactory guard

and corner freedom and safety

banking pins were opened for

Adjustment

lock.

The

slide.

6.

Drop locks satisfactory Out of angle Drop and shake close outside

The drop

locks being practically correct, the

to correct the condition of out of angle.

was

As

first

act

was

the out of angle

with the access of freedom on the side of the

slight

discharging pallet, the lever was bent in the direction toward the receiving pallet.

After banking to the drop and repeating

was found equal with regard

the several tests, the lever

the corner

freedom, but the drop was

condition being that of close outside.

by bending the reason

it

lever, the

draw was

inequal,

still

It will

the

be noted that

increased,

was decided that the receiving

to

and for

this

should be

pallet

tipped toward the pallet staff to equalize the drop.

This was

accordingly done and a test for draw followed, showing a satisfactory satisfactory.

condition.

All

The banking

Adjustment

tests

were

tried

and

found

pins were opened for slide.

7.

— correct Guard freedom — none Corner freedom — none

Drop

locks

After banking to the drop,

this

any guard and corner freedom. correct

it

was reasoned

escapement did not show

Since the drop locks were

that the lever

was too

long.

The

correction consists of grinding back the horns of the fork.


ESCAPEMENT ADJUSTING This

done by

is

which

Using

is

fitting to the lathe

turned to

oilstone

fit

121

an iron wire, part of

the curve of the horns of the fork.

powder and

oil,

the horns are ground

by-

holding the lever with a pair of cutting pliers against the iron wire.

Frequent applications of the corner

test

while

grinding prevented any possibility of overdoing the correction.

After grinding and polishing, the several

The banking

very satisfactory escapement action.

opened for

8.

— satisfactory

Condition of escapement

— guard pin jams against

In this example

we haye

roller table

single roller type of escapement.

After banking to the drop, the corner

found satisfactory. pin would

pins were

slide.

Adjustment Error

showed a

tests

jam or

When stick

the guard test

test

was

on the edge of the

was

tried

and

tried, the

guard

roller table.

This

error, responsible for frequent stopping, occurs occasionally in single roller escapements, but in double roller escapements

only

when

in the

the guard finger

is

The correction turning down and repolish-

loose or bent.

above example consisted of

ing the edge of the roller table and advancing the guard pin. All tests showing satisfactory conditions, slide

and the watch proved

Adjustment

to be

was added

an excellent timekeeper.

9.

— deep

Drop locks Out of angle

Draw

— wanting on both

pallets

This escapement was out of angle, with the excessive

guard freedom on the side of the receiving

pallet,

and since


A PRACTICAL COURSE IN HOROLOGY

122

the drop locks were deep and the

reasoned that

moving

all

draw was

was

it

by

faulty conditions could be corrected

The

discharging pallet.

in the

deficient

was accordingly moved

in

discharging pallet

and after rebanking

to the

drop

a thorough examination showed that the drop locks were correct; the lever's angular motion

was equal and the draw was should be remembered.

from the

line of centers

This example

satisfactory.

Errors of

frequently and the correction

is

this

kind occur quite

easy and the results are

certain.

Problems i.

What

2.

Define drop lock.

3.

State in degrees the correct

4.

What

5.

How

6.

Define draw.

7.

How

8.

Define drop.

9.

How

meant by "banked

is

to the drop" ?

amount of drop

lock.

meant by "out of angle"?

is

do you correct out of angle?

do you examine draw?

do you examine drop?

10.

Define shake.

11.

14.

What is the lift? What are the characteristics of a good action of lift? What is meant by the expression "loss in the lift" ? On what type of escapement is the loss in the lift greatest?

15.

State in degrees the total angular motion of the lever

12.

13.

escapement

is

when

the

banked to the drop.

16.

Should a watch run when banked to the drop ?

IT.

In what manner do you go about making the guard safety

test ?

corner safety test? curve test? 18.

What

is

the purpose of the guard safety test? corner safety

test? curve test?


ESCAPEMENT ADJUSTING What do

19.

the above tests aid in determining,

123 if

the drop locks

are correct ? 20.

Define

slide.

21.

When

is

22.

Give the specifications for a correctly designed escapement,

without

slide,

added?

slide

secondly with

first

slide.

altering the banking pins change the drop lock

23.

Does

24.

Define total lock.

25.

Does altering the banking pins change the total lock ? How do you correct an escapement in which the drop locks are

26.

correct but there

What

27.

is

is

?

an excessive guard and corner freedom ?

the error in an escapement that has a deep lock yet

the guard and corner

freedom are satisfactory?

If the drop locks are light and the guard and corner tests

28.

no freedom, what order

is

show

the correct procedure to put the escapement in

?

The drop

29.

locks are deep and the escapement

is

out of angle

with no guard and corner freedom on the side of the discharging pallet.

There

is,

however, too

the side of the receiving pallet. this

escapement ?

much guard and

How

corner freedom on

would you go about correcting


Part II

CHAPTER SEVEN Cleaning and Oiling Two METHODS that

we

are used in cleaning watches.

first

method generally referred

shall consider is the older

to as the

The

hand method. The second involves the use of the

cleaning machine.

The Hand Method In using the hand method we proceed as follows taking the

movement apart

string the larger pieces

loop, place the pieces in benzine, benzole, or

:

After

on a wire

any other good

cleaning preparation for several minutes.

Remove and wash

pieces in hot water, using castile soap

and a soft brush.

Rinse in clean water, dip in cyanide of potassium, rinse again in clean water,

immerse

The same treatment

is

and dry

in alcohol,

in

warm

sawdust.

given to the wheels and other small

pieces that can be strung on the wire loop, but separately,

The other small pieces jewels, may be held against

after the plates have been cleaned.

such as the pallet fork and the

a piece of hard pith or cork with a pair of tweezers especially

prepared for the purpose and brushed thoroughly with a fine

toothbrush previously dipped in benzole.

After being

brushed, the pieces are dipped in alcohol and allowed to dry

on a sheet of watch paper. separately.

The

The

usual method 124

is

balance must be cleaned

to dip the balance

first in


CLEANING AND OILING

125

benzole, then in water followed by cyanide, again in water

and

finally in alcohol,

The

parts are

now

after which

it

is

dried in sawdust.

dry and the jewels should be rubbed with

two pieces of pegwood, one which has been pointed so as to to

go through the holes and another that has been shaped fit

the cups of the jewels.

The watch having been

cleaned, the assembling

For example, the main spring

barrel with clock

oiling

Certain parts are oiled as the watch

are next in order.

put together.

and

is

oiled in the

The winding mechanism,

oil.

is

the escape

wheel, the pallet jewels, and the hole jewels where cap jewels are used in connection are also oiled in the process of

assembling.

The

train

is

oiled after the

watch

is

assembled,

The

cannon pinion.

also the center post that carries the roller jewel is not oiled.

The

Watch-cleaning Machine

The newer method of

cleaning watches with the cleaning

machine has some advantages.

Instead, an especially prepared cleaning solution

cyanide. is

eliminates the use of

It

The

used, together with water and a drying solution.

machine

is

particularly satisfactory for the cleaning of small

pieces like the pallet fork, the jewels,

and screws and has the

further advantage of eliminating the use of sawdust. Briefly, the

basket.

procedure

is

as follows

:

Place the parts in the

There are provided several small spaces for the

small pieces and one large space for the plates.

Lower

the

basket into the jar containing the cleaning solution and allow the motor to run for several minutes at a moderate speed.

Throw

off the cleaning solution

ciently to clear the

solution.

by raising the basket

Lower

sufifi-

the basket in a jar


A PRACTICAL COURSE IN HOROLOGY

126

containing water and rinse off the cleaning solution.

Next,

lower the basket in the drying solution and run the motor as Finally, allow the basket to spin in a receptacle

before.

containing a lighted electric light bulb for a quick drying of the watch parts.

Thus

the cleaning job

is

completed.

Problems 1.

Is

it

important that the jewels should be cleaned with peg-

wood? 2.

3. 4.

What parts of a watch do you oil? What parts should not be oiled ? Name some advantages in using the

cleaning machine.


PART

III

ADJUSTING


Part III

CHAPTER ONE

Preliminary Notes on Adjusting There

is

a greater

demand

for watches of accurate time-

keeping qualities today than there was years ago.

The

rail-

roads require that their employees' watches run within certain close limits

and the complexity of modern

need for greater accuracy

also.

close timing can be assured, a

ing

To

life

has shown a

repair watches so that

working knowledge of adjust-

necessary.

is

The

who

horologist

has never been concerned about the

theory and practice of adjusting has missed the real fascination

Aside from gaining

and satisfaction of watch work.

pleasure for himself, the repairman

of adjusting to his

work

will

who

applies the principles

win the respect of

and the sincere appreciation of

his

employer

his customers.

Adjusting consists in the execution of such manipulative operations of the balance spring and other parts as to cause a watch to function uniformly, the rate being within well-

defined limits under various conditions. urally divided into three branches:

(2)

isochronal adjusting, and

(3)

Adjusting

analysis

adjusting

is

all

temperature adjusting.

three are inseparable

completed. 128

nat-

(1) position adjusting,

These require independent methods of correction but final

is

when

the

in the

work of


PRELIMINARY NOTES ON ADJUSTING

129

General Observations Before considering the more complex problems

it

will be

must be as

well to outline briefly those conditions which

work can be attempted.

nearly perfect as possible before

THE MAIN TRAIN Close position and isochronal rating cannot be expected

Extreme

unless the

main

variation

often caused by defects in any of the train wheels

and

A It

is

train

is

in first-class condition.

especially in the center wheel

correct is

amount of end shake and

well, therefore, to

movements with regard

A

to train

and balance pivots should be round and pivot that

is

not perfectly round will

insert

is

round, but jewels

is

in

a

triangular piece,

we change

the jewel for

not round and repeat the experiment, the result

will be different.

and

The

steel

the

the jewel properly, will turn in the hole as perfectly

as a well-rounded pivot, but if

one that

To show

a three-cornered piece of

jewel that has a perfectly round hole. if it fits

also, the

slightest degree.

frequently do not have perfectly round holes. plainly,

important.

freedom and note,

function fairly well in a jewel hole that

effect

is

examine a number of high-grade

winding the mainspring even to the

well polished.

side shake

barrel.

wheel after the train runs down when

recoil of the escape

All train-wheel

and mainspring

will not turn.

The triangular piece will become wedged The effect exists in a lesser degree when

an imperfect jewel and an out-of -round pivot are used together, yet the

combined action of the two

affects the time-

keeping qualities of a watch.

Furthermore,

impossible to poise the balance

if

the

pivots of the staff are not round, and in this connection

we

it

is


A PRACTICAL COURSE IN HOROLOGY

130

recommend the

pivot

polisher

on

occasions where

all

This lathe attach-

balance pivot needs reducing or polishing.

ment

forms the pivots

(assuming the machine

perfectly

work quickly and with a

the

round and cylindrical

properly adjusted), and

is

a

it

does

factorylike polish.

INFLUENCE OF THE LEVER ESCAPEMENT ON THE ADJUSTMENTS The impulse communicated

to

the balance through the

escapement should take place at the moment when the balance spring

is

at its state of rest, that

spring

the

is

is,

moment when

at that

under no tension whatsoever.

This ideal

condition would permit the balance and spring to perform arcs of vibration in the

its

and

spring

same time

would perform these

mechanical means at one's

that a free balance

However, the

arcs.

disposal

to

keep the balance

vibrating does not meet the above requirements and one

is

obliged to take account of the following laws. 1.

An

impulse delivered

the point of rest 2. its

An

-will

to a balance or

pendulum before

accelerate the vibrations.

impulse delivered to a balance or pendulum after

point of rest will retard the vibrations.

This principle can be easily demonstrated with a simple

pendulum. its

Impulse given

point of rest causes

quickly than

if it

it

to a

pendulum before

it

reaches

to arrive at the point of rest

were acted upon by gravity

alone.

more Given

impulse after reaching the point of rest results in driving the

pendulum

farther, resisting the force of gravity

no particularly accelerated

rate, if any.

Hence a

and

at

retardation

takes place and the greater the distance the impulse takes place after the point of rest, the greater

is

the retardation.


PRELIMINARY NOTES ON ADJUSTING

Now

consider this factor in relation to the lever escape-

The

ment.

131

total

angular motion of the lever

The

allowing for 2 degrees of lock.

is

10.5 degrees,

relationship between

the acting length of the lever and the roller jewel radius 3.5 to

The

1.

would be

3.5

this figure

total lifting angle or contact

X

with the balance

Placing one half of

10.5 or 36.75 degrees.

on either side of the

is

we would

line of centers

have 18.375 degrees. However, the locking must be removed

from

that

contact before the line

portion of

(point of rest).

Thus

the line of centers

would be 18.375 â&#x20AC;&#x201D;(3.5

degrees. full

The impulse

amount or 18.375

of

centers

the impulse communicated before

X

after the line of centers

2)

=

11.375

would be the

degrees.

to the

above analysis a retardation would result

for the short arcs.

Further retardation occurs because of

According

the unlocking action, which

is

free motion of the balance.

Hence

carefully adjusted escapement in the fine position

a serious resistance to the

is

it

is

clearly seen that a

of the utmost importance

and isochronal rating of a watch.

WEIGHT OF THE ESCAPE WHEEL AND PALLET FORK The

escape wheel should be as light as possible consistent

The

with proper firmness.

sluggishness of a heavy escape

wheel directly increases the inequality of the impulse between the receiving

and discharging

of the draw and the

The

lift

on the

lever, too, should be

was formerly the

pallets pallets.

made

as light as possible.

It

practice of manufacturers to add a counter-

poise to the lever, supposing that close position rating.

strated that this

owing to the inequality

is

it

was necessary

to secure

Research into the problem has demon-

not necessary; in fact,

that lightness of the lever

is

of

much more

it

can be shown

importance.

The


A PRACTICAL COURSE IN HOROLOGY

132

counterpoise only gives the force at the circumference of

more work

the escape wheel

do and thus tends to make

to

the actions of the escapement and balance

more

sluggish.

MAINSPRINGS AND BALANCE MOTION

A

mainspring unwinding in a barrel generally does not

Were

take place in a concentric manner.

it

this ideal condition could be attained, there

act of

would be

Httle

coils

and a more smooth and

result.

This eccentricity in the

or no friction between the

even motive power would

possible that

unwinding varies with the type of brace or hook used

on the outer end of the

Experience has shown that

spring.

any type of hook that maintains a quarter turn of the external coil flat against the wall of the barrel gives it is

gratifying to note that

good

results

and

more and more manufacturers

are adopting some form of hook with this end in view. It is

important that the horologist use the very best main-

springs that

a good spring that

The

money can buy. is

so apparent in the position rating of a

no argument

Springs that are

superior performance of

is

watch

necessary to convince the most skeptical.

set,

even to a comparatively slight degree,

should be replaced with

new ones and

the mainspring winder

should always be used.

The proper arc of motion of the balance is 540 degrees when the watch is fully wound and lying in a horizontal position.

when a

Horologists experience a feeling of real satisfaction full

balance arc

is

attained with the fitting of the

weakest possible mainspring.

most even motive power

It

will be

is

an indication that the

maintained for the

hours of running and that there will be only a slight off of the balance arc at the

end of a 24 hours run.

full

24

falling-


:

PRELIMINARY NOTES ON ADJUSTING

How

The

to ascertain the arc of motion.

arise as to

how we

133

question

may

are able to ascertain this arc of motion.

This the eye can be trained to recognize easily and at a glance by using the following method is

at rest with the

roller jewel

between the banking

Suppose the balance

:

in the

Now move

pins.

midway

fork slot

the balance one half

of a circle or 180 degrees and stop.

Release the balance

and the force of the spring

to return to

will cause

it

its

of rest and 180 degrees farther on the opposite side. arc of motion would be 360 degrees. Again

move

its

the opposite

own power to side. The arc

and the balance

its

The arms

it

to

point of rest and as far on

of motion

will continue to vibrate

as long as the proper motive

The

the balance,

three fourths of a circle or 270 degrees, and allow

return on

point

power

is

is

now 540

degrees

between these points maintained.

moment

of the balance become visible at the

the

balance completes the arc of motion and starts in the opposite direction

time

on

when

its

return vibration.

It

is,

therefore, at that

the balance stops that

the arc of motion can be deter-

-

o

mined.

1,

With

the assistance of Figure

the

problem can be more

clearly explained in this

When

/3S^

manner

the balance vibrates 180 /^{fm^m^imt^

degrees and returns to

degrees

and continues as

on the

opposite side

arms are

â&#x20AC;&#x201D;that

visible at

â&#x20AC;&#x201D;the

and

degrees

tion is

360 degrees.

far is,

j^s

|

when

the

180 degrees arc of

When

^a^^^Mi ^

mothe

|

270" Figure

1

**


— A PRACTICAL COURSE IN HOROLOGY

134

balance vibrates 225 degrees and returns to continues as far on the opposite side are visible

first at

that

degrees and

when

is,

the

arms

225 degrees and 45 degrees and on

its

return vibration at 135 degrees and 315 degrees (forming a cross at right angles)

When

—the

when

the

arms are

the arc of motion

The

horologist

positions

and

if

is

on the opposite side

far

540 degrees. should examine the balance arc in

the motion

is

down.

made before any adjustment Note carefully

any difference between the arcs of

These positions should be

equal.

of pendant up, pendant right, pendant

The

down.

all

faulty in certain positions the

to position or isochronism is attempted. is

—that

270 degrees and 90 degrees

visible at

necessary corrections should be

there

450 degrees.

is

the balance vibrates 270 degrees and returns to

degrees and continues as is,

arc of motion

dial

up and

if

dial

Note

also the arcs

left,

and pendant

arcs for the vertical positions should be the

same although somewhat shorter than those for the two horizontal positions,

owing

to the increased friction

on the

balance pivots.

The

arc

of

motion should never be longer than 540

Experience has shown that an arc longer than the

degrees.

above figure produces a very fast rate for the

first

few hours

of running, after which time (the arcs becoming shorter) the watch functions at

its

normal

rate.

THE POISE OF THE BALANCE One

of the most

positions

is

common

causes of variation between

want of poise of the balance.

The

horizontal

positions are not affected but the error in the vertical positions is

considerable.

The

extent of the variation in the rate

in proportion to the extent of the error in poise.

is


PRELIMINARY NOTES ON ADJUSTING

on the lower side of the balance the watch will lose when the arc of motion is

// the excess of weight

when

135

at rest,

is

greater than 450 degrees, and will gain

when

the arc is less.

is

on the top side when the balance

is at

rest, the result will

be reversed and the watch will gain

when

If the weight

the arc of motion is greater tlmn 450 degrees

when

will lose

the arc is less.

Nature of error due to want of that the excess of weight

when

and

at rest.

Let us assume

poise.

on the lower side of the balance

is

Suppose the balance vibrates

at

an arc of

almost 360 degrees, and in doing so the weight will stop near

The

the top of the balance. the balance to

its

point of rest will receive an added energy

in that of gravity acting

the spring will return to

when

than

force of the spring in returning

This means that

on the weight.

its

point of rest a

little

more quickly

acted upon by the force of the spring alone.

Now

assume that the weight, after having reached the bottom, continues the arc on the opposite side. acting on the weight

is

The

force of gravity

an added resistance to that of the

spring; in other words, the result of an added weight in effect, the

same as

arc will be performed

Now and

if

is,

a stronger spring were used and the

more

quickly.

suppose that the motion

is

increased to 540 degrees

in vibrating to this extent the

weight starts from

its

point of rest at the bottom and turns three quarters of a circle

and stops

at right angles to

the center of the balance.

a vertical

The

line

drawn through

force of the spring will

encounter a resistance due to gravity acting on the weight as

it

starts

upward toward the

top,

and after reaching the

top and starting downward, the force of gravity force

downward.

The

effect

is

an added

would be a retardation during


A PRACTICAL COURSE IN HOROLOGY

136

the

first

portion of the path and an acceleration during the

latter portion to the extent that, for arcs

450 degrees the watch that at

will lose.

some point near

would seem, therefore,

It

450 degrees these forces would

Some

counteract each other. at

to

above approximately

authorities place this figure

444 degrees. Poising the balance.

and

Place the balance on a poising tool

start the balance in motion.

During the time

it is

rotating

hold a small compass as near as possible to the circumference of the balance so as to ascertain whether or not netized.

It

is

useless

balance; hence the

even the slightest

The

first

bit of

mag-

it is

to

attempt to poise a magnetized

act

is

to demagnetize

it

if it

shows

magnetism.

balance having been demagnetized and found satis-

Having located the

factory, proceed with the poising.

tion of the heavy point

it is

position of the regulator.

good practice to take note of the This

is

our guide

whether we should reduce the weight

add weight opposite to the heavy

amount of timing Should we

find,

after the

when

is

at the

in

deciding

heavy point or

point, thus saving a certain

watch

is

again running.

altering the weights, that the heavy

point has shifted a short distance

good progress

being made.

we may

However,

feel certain that

if it is

found that

the heavy point has been shifted to the opposite side

evident that the correction has been overdone. therefore, that in altering the weights

with caution and thereby save a

much

posi-

much

we

It

it

is

follows,

should proceed

time, besides realizing

better piece of work.

Parallel pliers with cardboard glued to the jaws are very effective for holding the balance while

the screws.

removing and replacing


PRELIMINARY NOTES ON ADJUSTING

137

MAGNETISM Magnetism

an ever-constant and insidious enemy to

The means by which a watch may be magnetized

horologists.

are so

is

numerous today

form the habit of comes

that

it is

important that the repairman

testing every

watch for magnetism that

in for regulation, examination or repair.

In testing for magnetism place a small compass not only

The

over the balance but also over the winding wheels.

mainspring being subject to magnetization as well as other steel parts,

has definite poles at the time the magnetic lines

These poles are

of force passes through the watch.

up

into countless

constant

split

numbers as the mainspring unwinds. of

alteration

the

position

relative

of

the

This poles

between the mainspring, winding wheels, and the balance helps

explain

to

the

performance of magnetized

erratic

watches.

Theory that type

An

of demagnetization.

of

electrical

alternating current

current that changes

is

direction

its

when such

current flows through a coil of

wire the poles also change.

Figure 2 shows a conception of

constantly and

an alternating current wave as the complete

wave

is

is

An

time,

and

alternating current

said to have a frequency of

cycles.

When

a

steel

rod

is

inserted in a demagnetizer

flow of alternating current will be

the current

was

suddenly cut

is left

its

off,

and the

the steel rod

poles being that of the

sent through the wire.

However,

on and the rod gradually withdrawn,

the result will be different. cycle

is

found to be magnetized,

last half cycle that if

moves through

called a cycle.

of 60 such waves per second

60

it

It will

be repolarized for every

and each successive polarization

will be

weaker than


A PRACTICAL COURSE IN HOROLOGY

138

Figure

Wave form

2.

When

the preceding one.

of alternating current

withdrawn

entirely

from the

field,

the magnetism has disappeared.

Demagnetizing a watch. The procedure in demagnetizing Withdraw a watch is much the same as explained above. the watch, keeping

it

central with the opening

a slight twist after leaving the opening.

drawal until the watch

is

it

Continue the with-

about three feet or more from the

If the first attempt fails to

demagnetizer.

and giving

remove

all

mag-

netism repeat the operation.

Magnetized

tools.

being magnetized. closely watched.

position in or

The

horologists' tools are subject to

Screw drivers and tweezers should be Avoid placing such

tools in a north-south

on the bench.

Problems 1.

Why

2.

What

should balance pivots be made perfectly round is

?

the effect of giving impulse to the balance or pendu-

lum before the point of

rest? after the point of rest?


PRELIMINARY NOTES ON ADJUSTING 3.

What

is

the effect of the lever escapement

139

on the position

rating of a watch?

on the

pallet fork of

very great importance?

4.

Is the counterpoise

5.

Does the type of fastening on the outer end of the mainspring

have anything to do with the friction between the coils? 6.

What

7.

How

8.

What

9.

If the excess of weight

when

is

the proper arc of motion of the balance

do you ascertain the correct arc of motion? is

the most

at rest, will the

540 degrees

?

common

cause of position error is

on the lower

watch gain or

when running

at

lose

side of the balance

an arc of 350 degrees ?

What

balance arc

11.

How How

do you go about poising the balance?

is

considered the neutral arc?

do you demagnetize a watch ?

?

when running

10.

12.

?

at

an arc of


Part III

CHAPTER TWO Position Adjusting The

first portion of this chapter treats on position error

as related solely to the balance spring and of the effect of

gravity which

most

coils.

is

is

such that a positive

produced.

from barrel

knows how

to

fection, there will

in

of this action

watch may be mechanically perfect

struction skill

an ever-present force acting upon the inner-

The nature

position error

A

is

to balance

make

it

may

â&#x20AC;&#x201D;and

â&#x20AC;&#x201D;that

is,

its

be as exact as

con-

human

such per-

yet, in spite of

be a variation of from 15 to 30 seconds

24 hours between some two

vertical positions

In watches that are

condition of the balance spring alone. less perfect the error is frequently as

due to the

high as 40 seconds or

more.

The Balance Spring and The

oscillation

Its Poise

of the inner portion of the spring cor-

responds very nearly to that of the collet travels three fourths of

a

collet

circle,

center travels nearly an equal distance.

;

when

the

first coil in

the

that

the It is

from the

movement ceases coils are marked

is,

further evident

that each of the several coils, as they tend to distant

Error

become more

center, will travel a shorter path until the

altogether at the regulator pins. in a straight line

140

from

If the

collet to regulator


POSITION ADJUSTING

141

one would readily observe the distance traveled by the

pins,

several coils

and the extent of

their path

under different arcs

of motion. It is

impossible to poise a spiral spring.

at once evident that

it is

portion of the spring,

Therefore

the oscillation of the unpoised inner

when

acted upon by the pull of gravity,

that causes position error in the vertical positions.

ment

how

as to

this

it is

works need not be repeated

A

state-

here, for

the analysis given in the preceding chapter relative to the poise error of the balance, applies to this condition also.

However, motion

slightly

result,

varied

effects

under different arcs of

due to the fact that the greater mass of the

unpoised inner portion of the spring vibrates in a shorter arc

than does the balance proper.

Experimental demonstration.

command

of every horologist

run them,

first

is

with the figure

1

A

demonstration at the

to take several watches

up, and following with the

figures 2, 3, 4, etc., continuing the experiment dial

with

all

and

around the

figures up, running the watches in each of the

12 positions for 24 hours and taking note of the rate in each position.

If

an

electric

timing machine

is

available the

experiment can be made most conveniently and

in

a very

short time.

Table

1

shows the

result of an experiment as stated above,

using four popular makes of American watches. All watches

were in excellent condition with balances perfectly poised, fitted

with theoretically corrected overcoils, and the grades

ranged from 17 jewels to 21 jewels. the balance of

all

The

arc of motion of

watches was about 540 degrees when fully

wound and more than 450 degrees after 24 hours of running. In watch Number 1 the rate was fastest at the time when


142

A PRACTICAL COURSE IN HOROLOGY

the figure

11

was up

;

in

watch Number 2 the rate was

fastest

when the figure 3 was up. The watches Number and Number 4 had definite fast positions also, and in all

at the time

3

watches the slow position was opposite or nearly opposite that of the fast position.

TABLE

1


POSITION ADJUSTING

Figure

3.

2.

Proper pinning at the

Reduce

collet.

Figure

4.

143

Proper pinning at the collet

the natural error by the application o,

correct

terminal curves both outside and inside. 3.

Neutralise the effect of the natural error by counter-

poising the balance.

These corrections

will

now be

considered In the order

stated above.

The proper pinning

at the collet.

When

fitting

new

balance springs to pocket watches, certain pinning points

should be observed expected.

Figures 3

upward

as

if

the best position rates are to be

The proper pinning at and 4. The first half of it

the collet

is

shown

in

the innermost coil tends

leaves the collet in the direction of pendant up.


A PRACTICAL COURSE IN HOROLOGY

144

producing a fast pendant-up

It

rate.

does not matter

if

the

spring tends to the left as shown in Figure 3 or tends to the

shown

right as

in Figure 4, for

can be readily seen

it

that,

in either case, the middle of the first half of the innermost coil is

the spring

pinned as stated above, the pendant-right and pendant-

left positions

will

have a slower but a nearly equal

provided the balance spring concentrically.

show up only watch

The

little

it

is

rate,

properly centered and vibrates

greater part of the natural error will

pendant-down

in the

in practical

position,

of

When

stands in the direction of pendant up.

usage

is

position,

seldom

and since a pocket

ever subjected to this

if

follows naturally that the pendant-down error

is

importance.

Reducing the natural

error.

It

was

stated in the first

portion of this chapter that finely constructed watches vary

from 15 positions

much to be

to

30 seconds

in

24 hours between some two

and watches that are

as 40 seconds and more.

more than 30 seconds

variation

is

less perfect

vertical

would vary as

If the natural error

is

shown

24 hours, the excessive

in

due to want of perfection of the inner terminal

of the spring.

A slight eccentric motion at the inner terminal

will cause a greater variation than

spring were perfectly true.

Thus

it

would be the case is

if

the

clear that the balance

spring should always be faultlessly trued at the collet and equal attention should be given to both the

The Breguet type balance spring on would now be natural for one to inquire

flat

and the round.

position error.

It

as to the effect of

the Breguet spring with correct terminal as compared with the ordinary

flat

spring on position error.

Experiments

have demonstrated that the Breguet spring does reduce the


POSITION ADJUSTING

145

variation in the vertical positions, but only to a small degree,

proving that the position error

is

due primarily

to

the

oscillation of the center of gravity of the inner portion of the

spring.

Table 2 shows the results of an experiment using both the

flat

and Breguet

example was an 18 spring.

The

springs. size,

15- jewel grade, fitted with a flat

column of the

rate with

and the second column shows the

rate with

the

flat

the

same spring after

correct terminal.

24 hours.

selected for this

shows the

first

spring,

The watch

it

table

was made over

The watch was run

into a in

Breguet with

each position for


:

A PRACTICAL COURSE IN HOROLOGY

146

Usually just a slight touch of the poising

rate will result.

saw in

will

reduce the natural error as

much

as 5 to 10 seconds

24 hours.

Use of the Regulator Pins The

in Adjusting

condition of the regulator pins play an important

In

part in the position rating of a watch.

may

opening or closing the pins as the case possible to

fact,

by

slightly

require,

it

is

bring the horizontal and vertical positions in

close agreement.

Let us suppose, for example, that the regulator pins are

opened

slightly

and the

first coil

We

between the pins.

have

of the spring vibrates equally

literally

made

the active length

of the spring longer and the watch will go slower.

It also

changes the rate between the long and short arcs. The effect

can be explained in this

way

Suppose that the balance degrees and the pins.

first coil

is

vibrating at an arc of 180

of the spring barely touches the

For arcs below 180 degrees, the

spring will

active length of the

commence very nearly from

the arc of motion

is

the stud.

and the

effect will

if

increased to 540 degrees, the active

commencing more

length of the spring will be shortened,

nearly from the pins.

Now,

This will make the long arcs go faster

vary

in

proportion to the changes taking

place in the arc of motion.

Suppose now that the pins are open, but instead of the first coil

first

coil

of the spring vibrating equally between them, the

Assume that it coil away from the

leans against one of the pins.

requires an arc of 360 degrees to

pin against which

it

leans.

lift

the

It is plain that for arcs

360 degrees the active length of the spring

will

below

commence


:

POSITION ADJUSTING from the

147

and for arcs above 360 degrees the active commence more nearly from the stud. This

pins,

length will

condition will

make

the long arcs go slower, or, in other

words, opposite to that in the former instance.

Thus

be seen that the condition of the regulator pins

may

cause of

many

an

intelligent

the quickest and simplest

in the vertical positions. is

The

vertical is

positions

always shorter

practical use of the regulator

stated in the following rules

If the regulator pins are closed and the watch gains

1.

in

is

means of correcting the variation

because of the fact that the arc of motion

pins

be the

manipulation of the pins

between the horizontal and

rate

can

of the disorders in the performance of watches.

It is also true that

in the

it

the

pendant-up position, a slower pendant-up rate

is

obtained by opening the pins. If the regulator pins are open and the watch loses in the pendant-up position, a faster pendant-up rate is obtained 2.

by closing the

The coil

pins.

spring should be so adjusted that the vibration of the

between the pins

is

equal

;

otherwise, the coil will strike

one pin with more force than the other, and the result will be very different from that stated in the above rules. Also in spreading the pins, the vibration of the coil

between them

should be very slight and discernible only with a powerful

The

glass.

pins should never be spread

more than enough

mean rate 3 seconds an hour. If spread beyond amount the watch is apt to become a very unreliable

to slow the

that

timepiece

;

in other words, position adjusting

lation of the regulator pins

extent.

by the manipu-

can be practiced only to a limited


A PRACTICAL COURSE IN HOROLOGY

148

Adjustment

Horizontal Positions

to the

on the

Effect of manipulating the regulator pins

We

zontal positions.

hori-

have seen that the rates between

dial

up and pendant up can be equalized by the manipulation of Should we

the regulator pins.

alter the pins to secure the

up and pendant up, we could

desired results between dial

expect a change in the rate between the horizontal positions

Often the horizontal

also.

they are reversed.

improved; sometimes

rates are

This would suggest that the adjustment

â&#x20AC;&#x201D;that

made last up and pendant up are

to the horizontal positions should be

the corrections for dial

After a

little

in the rate is

reflection

wise

it

dial

is

after

satisfactory.

evident that the difference

due to the anisochronism of the balance spring.

The manipulation tween

it

is,

of the pins not only corrects the rate be-

up and pendant up, but more often than

improves the isochronal rate

by running a given watch

other-

This can be shown

also.

in the position of dial

up for 8

hours at an arc of 540 degrees and taking note of the rate

and then running 360 degrees.

it

again for another 8 hours at an arc of

If the

rate

is

slower

when running

at

360

degrees the pendant-up rate will usually be slower. Occasionally there are exceptions.

Correction of errors in the horizontal positions. Errors

between the horizontal positions come generally under the

head of

frictional errors

and have

the arc of motion of the balance.

even 4 seconds laid to

Is

unimportant.

rough pivots,

to

A

do with changes

in

variation of 2, 3, or

Extreme

variation can be

dirt or thick oil, hole jewels that are

too small or too large, pitted cap jewels, balance pivots not the same size, or a balance spring out of

flat.

As

a rule the


POSITION ADJUSTING fast position takes the shorter arc,

which would suggest that

the position producing the fast rate

Assuming

correction.

149

that the staff

is

the one that calls for

and jewels are as nearly

perfect as an inspection with a strong glass can determine, a

general rule for the correction of the rate in the horizontal positions reads as follows

:

Round

slightly the

lower pivot in

the position that is fast.

Problems possible to poise perfectly a balance spring?

1.

Is

2.

What

it

is

the natural error

position rating of a

?

it

affect the

watch ?

2.

What

4.

Does the outer terminal of

is

In what manner does

the proper pinning at the collet

?

the balance spring have a greater

or smaller effect on the position rating of a watch as compared with the inner terminal 5.

Can

?

the regulator pins be of use in adjusting a watch to posi-

tion? Explain. 6.

What

positions

?

are the usual causes of position error in the horizontal


:

Part III

CHAPTER THREE

Adjustment to Isochronism The adjustment

to isochronism is that

adjustment which

has to do with the maintaining of a constant rate over a definite period of time.

Absolute isochronism

to attain because of several factors

is

impossible

which are inherent

in the

balance spring and for which there are no practical remedies.

A

pendulum

equal time.

will

Start a

make

the long and short vibrations in

pendulum

in motion, traveling over a

As

given space in a given time.

the motion falls

off, it will

be observed that the time consumed in each vibration does not change.

A

slower or faster rate can be produced only

by lengthening or shortening the pendulum. The pendulum is

in reality a

falling

body and the laws which apply

falling bodies apply to the

pendulum

also.

to

Therefore adding

or reducing the weight of the pendulum does not affect the

time of vibration, for any change

with

it

made

in the

mass

carries

a proportional force in that of gravity.

Adding

mass of the balance varies the

to or reducing the

rate of vibration, for the strength of the balance spring does

not change.

There are three

factors

upon which the time

of the vibration of the balance depends. They are 1.

2.

The weight of the balance. The diameter of the balance. 150


ADJUSTMENT TO ISOCHRONISM 3.

The

As

already stated, the balance spring

strength of the balance spring.

more important disturbing of watches. first

151

Of

is

the cause of the

factors in the isochronal rating

these disturbing factors, our attention will

be directed to the problem of isochronism as affected by

varying the total length of the spring.

The Length

of the Balance Spring on Isochronism

In every balance spring there

is

a certain length in which

the long and short vibrations are practically isochronal. if this

length is ascertained and

by whole

coils,

we

the short arcs will

Now

spring shorter

'tnake the

go faster; and

if

we make

the spring longer by whole coils, the short arcs will go slower. It will

be observed that the shortening or lengthening

done only by whole

coils.

The reason

in the following statement.

some portion of a

coil

for this

is

explained

If the spring is shortened

and not by whole

would take place which would

coils,

alter the isochronism.

is

one that

is

from the one now under discussion and

A is

For coil

cause the short arcs to produce a losing rate instead of

a gaining rate. This problem

more

by

another effect

example, the shortening of the spring by one half of a

may

is

in detail in the

spring that

is

distinctly separate it

will be treated

next section.

practically isochronal as far as the length

concerned usually consists of about 13

coils.

Springs

supplied by the manufacturer are correct for length.

The

thought to remember from that which has been stated above is

that in fitting a

new

spring, the spring should not be

shortened excessively in timing, for in so doing the isochronal rate

is

affected.


:

A PRACTICAL COURSE IN HOROLOGY

152

The Flat and Breguet Balance Spring on Isochronism

The

flat

spring.

If

one will examine a

watch during the time the balance observed that the vibration

is

in the spring,

in motion,

is

This

is

not

all

will be

the eccentric

however, for a similar motion

takes place opposite the inner terminal, although visible to the eye.

it

wholly on one side and on the

side opposite the regulator pins.

motion present

spring in a

flat

These eccentric motions

it

is

less

affect the iso-

chronism because of several conditions. The principal ones are:

(1)

a constant oscillation of the center of gravity,

(2) a persistent pushing and pulling at the balance pivots,

and (3) the

effect of

torsion, with

which

section

this

is

particularly concerned.

Action of the

flat

balance spring.

Torsion

is

a circular

impulse which takes place at the innermost coils of the spring.

The

result is a retardation or

an acceleration, de-

pending on the relative positions of the two eccentric motions as the balance vibrates.

The anisochronism thus produced Such

can be varied by altering the length of the spring. alterations, of course,

change the angular distance between

the inner terminal and the regulator pins, and

it is

this

change

of angular distance that decides the rate between the long and the short arcs.

The laws governing

the isochronism as con-

cerned with the above statement are as follows 1.

and coils,

2.

When

the angular distance between the inner terminal

the regulator pins stands at even coils, that

is,

whole

the short arcs gain.

When

the angular distance between the inner terminal

and the regidator pins stands the short arcs lose.

at

even

coils,

plus half a

coil,


ADJUSTMENT TO ISOCHRONISM

Figure

3.

When

Figure

5.

153

6.

the angular distance between the inner terminal

and the regulator pins stands three fourths of a

coil,

at

even

the long

coils

plus one fourth or

and short arcs are more

nearly isochronal.

Let us assume that the arc of motion of a given balance

360 degrees, as an example of a short pinned at even

coils,

opposite directions.

is

If the spring is

arc.

the eccentric motions will stand in

According to rule

produces a

this

1,

gaining rate as compared with the long arcs.

This can be

explained by reason of the fact that the eccentric motion of

(when wound up)

the outermost coils exerts a force direction

of the arrow A,

motion of the innermost

Figure

coil exerts

5,

in the

while the eccentric

a force in the direction of

the arrow B, and since these forces are in opposite directions, there

is

a tendency toward acceleration as the arcs become

shorter than 540 degrees and the degrees.

maximum

is

reached at 360

In unwinding, the forces are reversed but their

relation to each other

If the spring

is

is

the same.

pinned at even

coils plus half

eccentric motions will stand in the

opposite the regulator pins.

same

According

a

direction,

coil,

the

namely:

to rule 2, this pro-

duces a losing rate as compared with the long arcs. Since the forces of the eccentric motions are in the

same

direction,


A PRACTICAL COURSE IN HOROLOGY

154

Figure

6,

there

the balance

may

and

resistance or divergence of forces

is less

vibrate a

little

farther; hence a retardation

takes place. If the spring is

pinned at even

three fourths of a

coil,

coils plus

one fourth or

the eccentric motions will stand at

right angles to each other, the effects stated in rules will

1

and 2

be neutralized, and the watch will function at a more

nearly isochronal rate. practical

usage,

changing and

The

the

Of

course,

when

the watch

motion of the balance

is

is

put to

constantly

this fact considerably complicates results.

effect of torsion

should not be confused with that of

the oscillation of the center of gravity, for the latter

function that

is

distinctly different

part in producing an anisochronism.

is

a

and plays only a small

The

effect of torsion is

by far the most disturbing element and the only way its effect may be reduced, aside from varying the terminal pinnings,

is

the application of the most perfect terminal

curves, both outside and inside.

Reducing the isochronal

error.

The

superior perform-

ance of the Breguet spring in the attainment of isochronism is

the reason for the passing of the

analysis of the

flat

in

spring.

The above

spring would at once suggest that

possible to vary the isochronism coil of the

flat

it

is

by manipulating the over-

Breguet spring so as to throw the eccentric motion

some desired

direction.

That

is

correct reasoning;

how-

ever, a spring that produces concentric vibrations will attain close

enough isochronism

same time

in

most watches while

at

the

realizing the best position rating in the vertical

positions.

Modem

watches are built with a better design and pro-

portion of parts than the older models and the correction of


ADJUSTMENT TO ISOCHRONISM isochronism by

means of

seldom necessary.

altering

However,

if

a

correct

155

terminal

is

the most perfect terminal

curves do not produce the desired results, the following rules for altering the overcoil 1.

may be

used.

If the short arcs are slow, bring in part of the body of

the spring

and add

it

to the overcoil.

If the short arcs are fast, take part of the overcoil

2.

and move

it

back into the body of the spring.

Problems

What

1.

coils

is

the effect of shortening a balance spring

by whole

on the isochronal rating of a watch?

What

2.

What

3.

In what manner do you alter the overcoil to accelerate the

is

torsion ?

are the effects on a

flat

balance spring?

short arcs? 4.

arcs?

In what manner do you alter the overcoil to retard the short


Part III

CHAPTER FOUR

The Adjustment

to

Temperature

to attain a practical system for the temperature

In order

adjustment, the general practice has been to solder together brass and steel for the rim of the balance.

The

brass occupies

the outer portion of the rim, consuming about three fifths

of the total thickness.

The rim

is

cut near the arms to permit

the turning in and out of the loose ends, thus changing the active diameter of the wheel.

for

the

changing

elasticity

This movement compensates

of the balance spring during

known as the compensating balance. A compensating balance made of brass and Invar (a nickle-and-steel alloy) when used in temperature changes. This type of balance

is

connection with a hardened steel balance spring has been and is

today the most satisfactory arrangement for combating

the temperature error.

However, there

is

a definite trend toward the use of a

plain uncut balance of a single metal

and a balance spring

of a nonrusting, nonmagnetizing alloy,

chromium, and tungsten,

made

principally of

called

Elinvar.

A

iron,

nickle,

slight

temperature error exists, but there are certain advan-

tages that

make

improvement. tories,

for

it

desirable to continue research for further

This

is

apparently the opinion of watch fac-

new models have appeared 156

lately

with definite


:

ADJUSTMENT TO TEMPERATURE

157

changes in the design of the movement as well as the balance

and spring, showing a persistent facturers to improve this

new

effort

on the part of manu-

type of balance assembly.

Watches with com-

Correcting the temperature error.

pensating balances are usually adjusted to temperature be-

tween 40 degrees Fahrenheit and 95 degrees Fahrenheit.

The

rules for the adjustment are as follows

1,

If the watch runs slow in heat,

move any even number

of screws that are opposite each other an equal distance

toward the loose ends of the rims. 2.

If the watch runs fast in heat,

move any even number

of screws that are opposite each other an equal distance

toward the balance arms. Experience

temperature adjustment

in effecting

sary before the horologist the alterations.

More

is

able to decide

is

neces-

on the extent of

often than otherwise, several trials

are required. If the screws are

moved

the poise should be examined.

Temperature adjustment

practically permanent.

many

The

balance

considerable distance

may

is

be trued and poised

times without interfering with the temperature adjust-

ment.

However,

in

changing a balance spring, readjustment

would be necessary.

Equipment used ment used erator.

for temperature adjusting.

for temperature adjusting

An

is

The

equip-

an oven and a refrig-

oven suitable for the purpose need be nothing

more than a box fitted with an electric light bulb, a rheostat, and a thermometer. The thermometer is placed inside and in such a

manner

an opening

that

in the box.

it

can be conveniently read through

An

ordinary electric refrigerator will

serve the purpose for the lower temperature.


A PRACTICAL COURSE IN HOROLOGY

158

Problems 1.

Does the

fitting

of a

new balance

spring alter the temperature

adjustment of a watch? 2.

slow 3.

A

watch that

in heat.

Name

is

equipped with a compensating balance runs

How do you

correct the error

?

the advantages of a solid, single-metal balance and

Elinvar balance spring.


Part III

CHAPTER FIVE

The The

Work

Practical

of Adjusting

practical use of the instruction that has been written

these pages will presently be demonstrated by several

in

examples taken from actual practice when the writer was

engaged in practical work

The

at the bench.

data for the

watches to be adjusted are kept in a small notebook. date, customer's

name, the make,

size

The

and grade of the watch

are recorded, followed by the several rates and an account

made

of the changes

to effect a satisfactory rating.

Practical Problems in the Adjustment to Positions Preliminary notes. several

factors

The method

It will

be necessary to briefly discuss

before considering the concrete problems.

of computing the variation of the rate in the

different positions will be next in order

explanation, the reader 163. rate

The

â&#x20AC;&#x201D;that

first is,

is

referred to Adjustment 4 on page

the rate without setting the watch except at the test.

The

first

figure

seconds, the rate for 24 hours, written

Without

to assist in the

column, reading down, shows the progressive

beginning of the

up.

and

shows a

â&#x20AC;&#x201D;

2,

setting the watch, the figure

loss of

2

the rate for dial

below shows the

variation after running the watch in the position of dial

down, which

is -\-2.

The next

figure

159

below shows the varia-


A PRACTICAL COURSE IN HOROLOGY

160

tion after running in the position of pendant up, the rate

being

For pendant

19.

and for pendant

The

left the

progressive rate

rate for each period of

tracting the lesser figure

are

all

right the progressive rate

plus or

24 hours

from the

is

43.

computed by sub-

greater, provided the rates

minus. However,

all

is

—30

is

the rates are plus and

if

minus, the figures are added and the sign before the rate

added

prefixed to the 24-hour rate and entered in the

is

To make

second column.

the example, explaining

recorded as for dial

and the the

down

up

is

rate for pendant right

is

column as

-j-2

showing

-j-4,

The

-\-2

and