Fractional Aiming/Cue Ball

[Brookeland Bill]

I’ve been playing pool since 1961. There were no ‘aiming techniques’. I started reading about them online on the Billiard Digest site. Hal was one of the contributors and explained fractional aiming breaking down the object ball into fractions (1/2, 1/4 and 3/4). But instead of breaking down the object ball I began to breakdown the cue ball when aiming. It works and is just as well if not better than breaking down the object ball.

 

[Patrick Johnson]

I’ve been playing pool since 1961. There were no ‘aiming techniques’. I started reading about them online on the Billiard Digest site. Hal was one of the contributors and explained fractional aiming breaking down the object ball into fractions (1/2, 1/4 and 3/4). But instead of breaking down the object ball I began to breakdown the cue ball when aiming. It works and is just as well if not better than breaking down the object ball.

I'm sure it can be made to work either way with familiarity, but it seems to me that aiming with the center of the CB makes it more likely that the cue will be on or near that line.

pj
chgo

 

[heater451]

I’ve been playing pool since 1961. There were no ‘aiming techniques’. I started reading about them online on the Billiard Digest site. Hal was one of the contributors and explained fractional aiming breaking down the object ball into fractions (1/2, 1/4 and 3/4). But instead of breaking down the object ball I began to breakdown the cue ball when aiming. It works and is just as well if not better than breaking down the object ball.

So, would that mean aiming say the edge of the cue ball to the center of the target ball, or like the 1/4 or 3/4 quarter point of the cue ball, to certain points on the target? A more specific example: Left-cut, with left 1/4 point (half way from the left 'edge' to the vertical centerline of the cue ball, to the right 'edge' of the target ball?

 

[Magictrat007]

I’ve been playing pool since 1961. There were no ‘aiming techniques’. I started reading about them online on the Billiard Digest site. Hal was one of the contributors and explained fractional aiming breaking down the object ball into fractions (1/2, 1/4 and 3/4). But instead of breaking down the object ball I began to breakdown the cue ball when aiming. It works and is just as well if not better than breaking down the object ball.

I personally break down the cue ball and use the center of the object ball

 

[Patrick Johnson]

I personally break down the cue ball and use the center of the object ball

I like aiming the center of the CB at fractions on the OB (the usual way) so I have my stick and eyes aligned more often. The sighting advantage works for me even for shots (most) that aren’t aimed exactly center ball-to-fraction or are hit off-center.

pj
chgo

 

[Magictrat007]

I like aiming the center of the CB at fractions on the OB (the usual way) so I have my stick and eyes aligned more often. The sighting advantage works for me even for shots (most) that aren’t aimed exactly center ball-to-fraction or are hit off-center.

pj
chgo

Yea it’s basically the same thing just different perspectives. When I chop up the cue ball distance seems easier. I don’t have to look as the way to the object ball. But wat do I know ??

 

[Bob Jewett]

Fractional ball aiming has been a standard technique that was taught in billiard books since the 1800s or even earlier. Usually it was 3/4, 1/2 and 1/4, but occasionally there were more divisions. Here is a drawing from a book over a century old (1911) that breaks the ball down into 16ths.

 

[Patrick Johnson]

Fractional ball aiming has been a standard technique that was taught in billiard books since the 1800s or even earlier. Usually it was 3/4, 1/2 and 1/4, but occasionally there were more divisions. Here is a drawing from a book over a century old (1911) that breaks the ball down into 16ths.

View attachment 841899

Very cool find, Bob. I'm guessing the cut angles increase logarithmically?

pj
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[Bob Jewett]

Very cool find, Bob. I'm guessing the cut angles increase logarithmically?

pj
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No. They go as a different function called arcsin(). It means "the angle whose sine is the given fraction of a radius." The important distance is how far from the center (measured perpendicular to the path of the cue ball), the object ball is struck. So, it the object ball is contacted full ball, that distance is zero and the arcsin(0) is 0 degrees of cut. If the object ball is contacted at 15/16ths of the radius from center, the cut angle is about 70 degrees. That's the thinnest hit shown in the diagram.

 

[Patrick Johnson]

No. They go as a different function called arcsin(). It means "the angle whose sine is the given fraction of a radius." The important distance is how far from the center (measured perpendicular to the path of the cue ball), the object ball is struck. So, it the object ball is contacted full ball, that distance is zero and the arcsin(0) is 0 degrees of cut. If the object ball is contacted at 15/16ths of the radius from center, the cut angle is about 70 degrees. That's the thinnest hit shown in the diagram.

So I take it arcsine(fraction) calculates the angle from the fraction and sine(angle) calculates the fraction from the angle? Nice to know (for an uneducated mathnerd like me). Makes it easy to make a chart like this:

pj
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[Bob Jewett]

So I take it arcsine(fraction) calculates the angle from the fraction and sine(angle) calculates the fraction from the angle? Nice to know (for an uneducated mathnerd like me).

pj
chgo

Yes. If you stick "arcsin(1/2) in degrees" into google search, it will tell you that a half-ball hit is 30 degrees.

For "arcsin(1/4) in degrees" you get 14.5 degrees (about 15) for a 1/4 cut or a 3/4 full hit.

For those who prefer to think in fullness rather than amount of cut, you can instead do something like:

arcsin(1-fullness) in degrees

so "arcsin(1-1/4) in degrees" , which is a quarter-ball hit, gives about 48.6 degrees.

The "degrees" is necessary in the search because the standard measure of angles in math is "radians", with 2 pi radians in a circle (360 degrees).

 

[Patrick Johnson]

If you stick "arcsin(1/2) in degrees" into google search, it will tell you that a half-ball hit is 30 degrees.

Another good tip - thanks again.

pj
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