Bob Jewett

14 page November 2013

A BASIC AIMING SYSTEM Bob Jewett

Sometimes I balls are three OB think beginners dimensional. CB believe too The cue ball will CB&OB OB CB OB CB much in aiming always appear systems. They larger than the Full 1/2 Full 1/4 Full 3/4 Full think that if object ball at its they just find starting point the right way and even at the to look at the time of contact cue ball, object because it will be CP ball and pocket, nearer to you. CB they will never miss again. Besides full ball Unfortunately, and half ball OB Half ball hit seen from above there is no such are 1/4th or system. Aim “quarter” ball varies with balls cloth, stick, speed, spin, humidity, and 3/4ths full. To aim for a half ball hit, you actually and where your head is, literally and figuratively. All have a visible target: the edge of the object ball. Your systems, or at least the ones I know about, ignore some stick should be aimed directly through the center of or most of those factors. the cue ball at the edge of the object ball. For 3/4 full, you sort of have a target if your stick is pointed The only way to learn how to aim is to play and half way from the center of the object ball to the edge. develop a feel for angles, but that’s not to say that all For a 1/4 full shot, your stick must be aimed as much systems are worthless. A system can provide a first outside the edge of the ball as the 3/4 shot was aimed estimate of the line of a shot that you have no feel inside the ball. for, which will frequently be the case if you are just beginning to play seriously. If you practice with one, In the lower diagram is view from above of a half-ball it can give you confidence in times of stress. A system hit to make things a little clearer. Note that the edge will usually make you look at the shot, and that alone of the cue ball is going towards the center of the object will improve your play if you’ve gotten into really lazy ball, just as it’s center is going towards the edge of the habits. Finally, a system will organize angles into a object ball. Also drawn is a line half way between structure that may be easier to understand than if every the two “centerlines” which turns out to give the shot is separate and unconnected to shots at slightly two points on the balls that actually make contact at different angles. “CP.” This demonstrates that the stick is almost never pointed at the spot on the object ball you actually want The fractional ball aiming system has been with us for to contact. perhaps 200 years -- it appears in a book by Edwin Kentfield that was published in 1839. The basic idea Geometry tells us the cut angles for each of these four is simple: any cut angle is described by “how much” cardinal fullnesses of hit. Full ball is pretty obviously of the object ball the cue ball hits. If the cue ball is a cut of zero degrees. Half ball is 30 degrees, which directed straight at the object ball, it is said to hit the can be shown pretty easily with equilateral triangles, object ball “full.” If the center of the cue ball is sent if you retain some of your high school geometry or towards the exact edge of the object ball, it is said to mechanical drawing. It’s a little harder to work out hit “half ” of the object ball. If the cue ball barely that 3/4 full is a cut of 14.48 degrees, and 1/4 full cuts grazes the edge of the object ball, for a cut of nearly 90 the ball 48.59 degrees. A friend of mine memorized degrees, it is a “very thin” hit. the cut angles for thicknesses down to 64ths, so he could tell you that 51/64ths full is a cut of 12 degrees. Various thicknesses of hit are illustrated in the top I think the 1/2 ball angle is plenty for most people, diagram. Shown is how much the cue ball overlaps since you have to judge the angles by eye anyway. the object ball from the tip’s-eye-view. Of course the diagram is a simplification, since the balls are Even if you don’t use the idea of fractional ball hits to drawn as equal-sized two-dimensional disks, and real aim, it is very useful to describe how full a shot is hit.

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