Building wooden machines

Page 58

FIGURE 5-8 Whittle a.a,. tha l.adlng odg8 of tb. key so It fits In the Dotch OD tbe underside of tha latch.

FIGURE 5-7 Cut Gut tba leay au,p. an the drill and scroll U•• and whittle tb•

•talk ao W. an ••ay°la-tarD fit io the '/."·diam.ur boa bola.

II

Having IIrst cut out the basic shape 01 the key blank (Fig 5-7). whittle the stem to a round section

so it fits in the keyhole, and shape the leading edge 01 the key (Fig 5-8) so. when it Is turned. 1t catches the notched

und erside 01 the tatch plate. with the eUect that the latch slides torward.

II

The trick to litting the key Is 10 trim back little by little. stop and have a fitting. trim back some more

and so on (Fig 5-9) until the movement is just right.

FIGURE 5-9

II

Continue whittling the leading edge of the --V to shape ao when

When you have cut the key to a good fit. then comes

the lrustrating task 01 li l t ing the tumbler. II you look

it tura.. it catche. and move, tile Blid.ing latch plate.

at the mechanism (Fig 5-10). you will see that the little,

shaped profile 01 the tumbler has twa dowels: the one on

the tar right. which Is the pivot. and the one at tall center.

which is a peg or knob. In action, the turning key catches and lilts the curved underside 01 the tumbler. with the

7

.....,

ettect that it swings up on its pivot. And, 01 course, as

the tumbler rises, the peg is lifted out of the notch on

the top edge of the latch. and the turning key goes on to move the latch

.

I'!I IIiI

Once again. you might weil have to cut two or three

tumbler plates and play around with the position of

the pivot hole and the shape of the underside curve betore

vou get it just right.

FIGURE 5-10 Sbape lUld fit lb.e tumbler. Evantu..alJy, tile pivot peg needs to be glued into tbe tumbler plate and held in plac. with a I'OIuld tootllpick with tile heelead of the pivot running heck tbrough the hoa. The otJaer dowel i. DO more than a stub that sticks out at tile back of the tumblar plate-to rut in tha l.teh uotch.

5&

WARD LOCK AND KEY


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