Is there any way to determine cut angle in degrees?

[Tramp Steamer]

I tried that system many years ago and was promptly ejected from the poolhall. Something about magic-markers being hard to get out of table cloth. Peace.

 

[Jal]

If you want to compare the angle of the cut on the OB from the CB to see how close it is to say 30 degrees (peace sign) so that you can see if it is a few more degrees than 30 or a few more degrees less - it's on the pool table.

From say the left corner pocket, the pocket diagonally across to the right far pocket is 30 degrees - at this pocket to it's long rail. ...

LAMas, a nitpick, but on a table constructed to very tight tolerances, the angle (~ 30 deg.) is actually 26.565051177077989351572193720453 (= arctan [1/2]).

A better approximation would be to use a line from the corner pocket (intersection of adjacent short and long cushions) to one diamond short of the diagonally opposite pocket (7'th diamond) along the long cushion. On the same carefully crafted table, this angle is 29.744881296942223734902311717887 deg. (= arctan [(1/2)/(7/8)]).

Even better would be a line from the corner pocket to a point 1/2" outward (toward the marker) from the nose of the cushion at the 7'th diamond. On a 9' table (100" X 50" playing surface, sloppily thrown together...relatively speaking ), this is an angle of ~29.9911 (~arctan [(0.505)/(7/8)]).

Jim

 

[LAMas]

Retract question.

26.565051177077989351572193720453 degrees.
No wonder I have been missing my spot shots from the rail at the head string/inside of the kitchen and aiming 1/2 ball.....all of these years.

Spot shots?....what's that when they are giving ball in hand.LOL
Thanks.

 

[randyg]

Isn't this fractional aiming which is similar to SAM except you are using say 1/3 1/2 1/4 1/8 instead of SAM 1, SAM 2, SAM 3 etc....?

Absolutely, YES! S.A.M is also aiming with your cue stick....SPF=randyg

 

[dr_dave]

Why is it you want to be able to judge the cut angle value to within 5 degrees? How does this number help you with aiming? I can see how recognizing where you are relative to 30 degrees might be helpful for using the center-to-edge 1/2-ball-hit reference. Do you plan to use the cut angle value to estimate the required ball-hit-fraction or the Joe-Tucker-contact-point-to-contact-point number?

I was hoping booville or others would share their thoughts on why knowing the cut angle might be useful at the table. What do you guys have in mind?

Thanks,
Dave

 

[duckie]

The actual degree of the cut is useless. You can not tell the difference between 28 degrees or 30 degrees.

What is of utmost importance has how the degree of cut affects the transfer of energy from the CB to the OB. The greater the cut, the less transfer of energy.

 

[pooltchr]

Is there a reliable way to determine the actual cut angle of a shot, say within five degrees? .

To answer the question you asked, you can think of the face of a clock. Reletive to straight up noon, 15 minutes would be 90 degrees, 5 minutes would be 30 degrees, 2 1/2 minutes would be 15 degrees.

Each minute is 6 degrees.

I believe that was the question you were asking.

Steve

 

[LAMas]

To answer the question you asked, you can think of the face of a clock. Reletive to straight up noon, 15 minutes would be 90 degrees, 5 minutes would be 30 degrees, 2 1/2 minutes would be 15 degrees.

Each minute is 6 degrees.

I believe that was the question you were asking.

Steve

That is a great way. I will go out and buy me a pocket watch so that I can take it out and rotate it on the table to determine where I should aim to make the cut to the correct angle.

 

[pooltchr]

That is a great way. I will go out and buy me a pocket watch so that I can take it out and rotate it on the table to determine where I should aim to make the cut to the correct angle.

You must be one of those young whippersnappers who grew up knowing only digital clocks. Us old farts have a pretty good idea of what an old time clock face looks like in our head.


Of course, you always have th option of carrying a protractor with you and just measuring every angle....but you might pizz of a few people doing that!

Steve

 

[Calgaryplayer]

Com' On............. are pool players supposed to have a PH.D degree in physics and Maths????

 

[LAMas]

You must be one of those young whippersnappers who grew up knowing only digital clocks. Us old farts have a pretty good idea of what an old time clock face looks like in our head.


Of course, you always have th option of carrying a protractor with you and just measuring every angle....but you might pizz of a few people doing that!

Steve

Actually, analog watches are in vogue to Casio's demise. I would need a larger pocket watch to discerne the angles for my analog wristwatches are too small and hard to move the hands to the proper angle.

I am old enough to remember the face of an analog watch but I have difficulty with one minute representing 6 degrees.

Do they make smaller 90 degree protractors or just 180 degree ones? I better find a better way of aiming if I want to play speed pool.

Hmmmm....maybe CTE? Naw...again too slow?

 

[Robert Raiford]

The actual degree of the cut is useless. You can not tell the difference between 28 degrees or 30 degrees.

Actually, I (and my students) can do better and measure any shot with 1 degree accuracy with hardly more than a glance. It can be very helpful in all kinds of ways beyond simple precision aiming, especially if you also play other games like 3-cushion that require precise caroms and spin control when hitting different amounts of object ball. The method I developed (and will soon be publishing) was originally developed for billiards to avoid kisses and play position, but I soon found that it directly translates to pool as well since the physics is identical.

What is of utmost importance has how the degree of cut affects the transfer of energy from the CB to the OB. The greater the cut, the less transfer of energy.

Exactly. But the more precisely you know the degree of cut, the more precisely you know just what that trade-off is and can make better predictions at the table. Of course, the human mind is a powerful thing, and you can learn this through thousands of hours of trial and error. But there are definitely ways to shortcut the process if you have a good model to work from and don't mind incorporating a little analysis into your game.

Robert

 

[poolplayer2093]

Is there a reliable way to determine the actual cut angle of a shot, say within five degrees? Years ago, I vaguely recall a system where one would draw a line from the pocket though the object ball and extend it into the rail. Then do the same for the cue ball...from the pocket to the rail; then there was a formula one could apply. However, I know there is an easier way to get within +/- five degrees. Any thoughts? Yes, I'm aware that a peace sign with your fingers is approximately 30 degrees, but frankly for me it's of limited use. Thanks in advance for your help.

get out your protractor. then you can be that guy at the pool room with a protractor that thinks just because he knows the exact degree the ball needs to be cut it'll be easier to cut it in

 

[dr_dave]

Actually, I (and my students) can do better and measure any shot with 1 degree accuracy with hardly more than a glance.

Are you willing to share with us how you do this?

It can be very helpful in all kinds of ways beyond simple precision aiming

How do you use the cut angle value to help you with precision aiming? Do you use it to estimate the required ball-hit fraction or CB/OB contact points? If so, are you willing to share how you do this?

Thanks,
Dave

 

[rayshooter22]

I believe he stated...

Are you willing to share with us how you do this?

How do you use the cut angle value to help you with precision aiming? Do you use it to estimate the required ball-hit fraction or CB/OB contact points? If so, are you willing to share how you do this?

Thanks,
Dave

According to his previous post...

The method I developed (and will soon be publishing)

Looks like the rest of the pool world will just have to wait a little while longer...

 

[Jal]

....26.565051177077989351572193720453 degrees.
No wonder I have been missing my spot shots from the rail at the head string/inside of the kitchen and aiming 1/2 ball.....all of these years.....

Bob J. once worked out that on a spot shot--assuming you're set up for about a 30 deg. cut as you've indicated, and that you stroke through the center of the CB--the butt of the cue has to be within 1/32" (+ or -) of the exact aim line in order to be successful! I think this was based on something like 4-3/4" pockets and a 9' table, i.e., not excessively tight pockets.

Looking at it that way, on the face of it, it's hard to believe anyone could make them with any consistency. After moving the entire cue 6-12" during one's stroke, to be within 1/32"? Yet, while I wouldn't necessarily describe spot shots as easy, I think you'd agree they're not terribly difficult either. (I'm pretty sure you were kidding too.)

Jim

 

[Robert Raiford]

Are you willing to share with us how you do this?

Absolutely! That's why I teach and am publishing the material I'd love to have you as a technical reviewer, so let me know if you're interested. The method itself is confidential, however, until it's publicly released.

Robert

 

[dr_dave]

Absolutely! That's why I teach and am publishing the material I'd love to have you as a technical reviewer, so let me know if you're interested. The method itself is confidential, however, until it's publicly released.

I'd be happy to be a technical reviewer. Feel free to give your publisher my contact info (PM or e-mail me for this).

Good luck with your project,
Dave

 

[Bob Jewett]

Bob J. once worked out that on a spot shot--assuming you're set up for about a 30 deg. cut as you've indicated, and that you stroke through the center of the CB--the butt of the cue has to be within 1/32" (+ or -) of the exact aim line in order to be successful! I think this was based on something like 4-3/4" pockets and a 9' table, i.e., not excessively tight pockets.

Looking at it that way, on the face of it, it's hard to believe anyone could make them with any consistency. After moving the entire cue 6-12" during one's stroke, to be within 1/32"? Yet, while I wouldn't necessarily describe spot shots as easy, I think you'd agree they're not terribly difficult either. (I'm pretty sure you were kidding too.)

Jim

The article about this is here. If you take the compensation from back-hand english into account, the calculation is somewhat different.

 

[LAMas]

Bob J. once worked out that on a spot shot--assuming you're set up for about a 30 deg. cut as you've indicated, and that you stroke through the center of the CB--the butt of the cue has to be within 1/32" (+ or -) of the exact aim line in order to be successful! I think this was based on something like 4-3/4" pockets and a 9' table, i.e., not excessively tight pockets.

Looking at it that way, on the face of it, it's hard to believe anyone could make them with any consistency. After moving the entire cue 6-12" during one's stroke, to be within 1/32"? Yet, while I wouldn't necessarily describe spot shots as easy, I think you'd agree they're not terribly difficult either. (I'm pretty sure you were kidding too.)

Jim

I diagrammed it in Acad and a spot shot needs to be hit within +/- .035" of the contact point going to a 4.0" pocket.

I used to shoot spot shots pretty good years ago playing, 5 & 9 ball, and payball ring games - came in handy.

What you said about the diagonal on a pool table being closer to 26 degrees and not 30 degrees ala H. H., got me thinking that shooting a spot shot from the kitchen with the CB against to side rail wasn't 30 degrees either - something less.

Since I used top on the CB from there, the OB went to the pocket with contact induced throw to decrease the angle - I never realized that before.
Thanks.:smile: