Angle Calculations?? Bob Jewitt??

The Renfro

The Renfro

Outsville.com
Silver Member
Dain Bramage kicked in... Was Bob and not Dr. Dave!!!!

Does anyone have a link to the system Bob Jewitt used awhile back for calculating cut angles based off the diamonds and the cueball offset in inches? I tried looking for it at the colo site and on Dr.Daves site but noooo luck....

Was taken from the thread concerning a cut shot made by Huidji See.

Bob Jewett said:
It was a great shot under the circumstances. The actual angle is fairly easy to calculate. If you take a line from the pocket the 9 goes in to through the 9 and to the side rail, it meets the rail at about 3.5 diamonds. That means that the path of the 9 ball forms about a 40 degree angle with the far end rail. For the path of the cue ball, it's a little hard to tell, but it looks to me like the ghost ball is about 8 inches farther from the left cushion than the cue ball, and the cue ball travels about 80 inches to the 9. This means that the cue ball is shot away from the cushion at an angle of about 6 degrees. That would make the cut angle 90-40+6 = 56 degrees. Making the shot much tougher are shooting from the rail and the long distances involved.

A standard tough cut at one pocket is making a spot shot from the jaws of a head pocket (after your opponent has pocketed a ball there and the ball spots) into the "wrong" foot pocket. That angle is about 64 degrees, but as a shooter it looks paper thin.
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If a line across the table has a slope of 3.5 diamonds in 4 diamonds, then the corresponding angle is "arctan(3.5/4.0) in degrees". If you stick exactly what's between the quotes into Google search, it will tell you 41.1859252 degrees. Or you could use a scientific calculator. If you want the exact angle of the path relative to the cushions, you have to worry about exactly where you measure the distances and whether to include the diameter of the ball in the calculations.
 
I see!!!! So the 6 degrees was the arctan of 8/80.... Applied mathematics is great. Goes back to the if you don't use it you lose it... Thanks for the refresher... Hope to see you at The Open again this year!
 
The Renfro said:
Dain Bramage kicked in... Was Bob and not Dr. Dave!!!!

Does anyone have a link to the system Bob Jewitt used awhile back for calculating cut angles based off the diamonds and the cueball offset in inches? I tried looking for it at the colo site and on Dr.Daves site but noooo luck....

Was taken from the thread concerning a cut shot made by Huidji See.
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Frankly Chris. I can't see how knowing the precise degree of the angle helps anything. In my pea sized brain those details do nothing but confuse the issue. Any way you look at it, you just have to shoot how you feel it's necessary to make the shot. The same goes for all those "quarter ball" hits and such. If you can't make it by feel alone you'll probably dog the shot.
 
cuesmith said:
Frankly Chris. I can't see how knowing the precise degree of the angle helps anything. In my pea sized brain those details do nothing but confuse the issue. Any way you look at it, you just have to shoot how you feel it's necessary to make the shot. The same goes for all those "quarter ball" hits and such. If you can't make it by feel alone you'll probably dog the shot.
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I agree with you for short cuts. However, these things mind come in handy especially if you're back-cutting over a long distance... And to answer your question (quote from dr. dave's link):

If you know the cut angle, you know where to aim from the CB center. 1mm per degree up to 30 degrees and above that, 0.8mm/degree off ball edge over 30 degrees covers it pretty well. Ball landmarks come in handy. A visible gap becomes apparent between cloth and ball at about 10mm off center (napped), 7-8 mm worsted. A 20 degree cut can be aimed at 7:30 or 4:30 on the clockface, a 25 degree shot at 8:00 or 4:00. A 23 degree cut is 2mm shy of a 25 and 3mm more than a 20.
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Heyas Sherm......

I likely wont actually calculate anything during a game but for practice I decided to mark the table up with the angles from the corner pocket to the diamonds to help mentally categorize shots. I yanked one of the corner pocket webbings loose and have been doing nothing but hitting 200-600 balls into a trashcan under it most nights for the last 6 weeks.

I have noticed an increase in overall percentages but am also noticing certain angles that I tend to miss pretty consistently. I am a firm believer in that the easiest way to defeat an enemy is thru knowledge so being able to calculate the angles gets me 1 step closer to defining the problem range and setting about coming up with new ideas for correcting those.
 
cuesmith said:
... I can't see how knowing the precise degree of the angle helps anything. ...
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Well, maybe, but....

Suppose you had a special baseball cap and every time you got down on a shot, it would whisper in your ear something like, "thirty seven point two degrees." Just suppose. I'm betting that a beginner would get better a lot faster. He could fit the true angle in with how the shot looked and felt.

Also, I know someone who beats me like a rented mule at one pocket who can actually tell you the angles. I know he can because I programmed the calculator he used while practicing and he already knew most of the angles. Maybe it helped him or maybe not, but there is the possibility that it did.
 
cuesmith said:
Frankly Chris. I can't see how knowing the precise degree of the angle helps anything. In my pea sized brain those details do nothing but confuse the issue. Any way you look at it, you just have to shoot how you feel it's necessary to make the shot. The same goes for all those "quarter ball" hits and such. If you can't make it by feel alone you'll probably dog the shot.
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Don't waste your time. Let them have their angle calculation formulas.
 
Bob Jewett said:
Well, maybe, but....

Suppose you had a special baseball cap and every time you got down on a shot, it would whisper in your ear something like, "thirty seven point two degrees." Just suppose. I'm betting that a beginner would get better a lot faster. He could fit the true angle in with how the shot looked and felt.
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I doubt that information would help a beginner get better faster - probably the opposite (having them memorize 90 different relationships, or 900 based on your example). Exact angles in degrees for the most part can't be identified during the course of actual play and if they could -- it's worthless unless it's zero degrees or 30.

Out of the last 500 games of 14.1 I've played, I couldn't tell you a single shot's cut angle in degrees and it has never affected the outcome of any game.

Beginners progress off the simplification of pool, not the complexity of it.

I'll prob get torched-in for disagreeing with the grand puba; but, if we each took a rank novice and spent 1 hour with them--- your guy/gal wouldn't know which end was up (sweating degrees) and my guy/gal would be in danger of pocketing balls. :)
 
risky biz said:
Don't waste your time. Let them have their angle calculation formulas.
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I don't see how learning the angles is a waste of time, even if you shoot strictly by feel. It seems logical to me that the more information you know about a particular shot, the more it will help you. It might not help you every time, but that one time might help you significantly.
 
Bob Jewett said:
If a line across the table has a slope of 3.5 diamonds in 4 diamonds, then the corresponding angle is "arctan(3.5/4.0) in degrees". If you stick exactly what's between the quotes into Google search, it will tell you 41.1859252 degrees. Or you could use a scientific calculator. If you want the exact angle of the path relative to the cushions, you have to worry about exactly where you measure the distances and whether to include the diameter of the ball in the calculations.
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This is entertaining on a forum, but has nothing to do with actually playing the game. It's almost like trying to figure out the angle of a chess piece as it moves from one square to the other (maybe that's 45 deg, maybe not...). Nevertheless, I'm taking their queen and they're in check.
 
SpiderWebComm said:
I doubt that information would help a beginner get better faster - probably the opposite (having them memorize 90 different relationships, or 900 based on your example). Exact angles in degrees for the most part can't be identified during the course of actual play and if they could -- it's worthless unless it's zero degrees or 30.

Out of the last 500 games of 14.1 I've played, I couldn't tell you a single shot's cut angle in degrees and it has never affected the outcome of any game.

Beginners progress off the simplification of pool, not the complexity of it.

I'll prob get torched-in for disagreeing with the grand puba; but, if we each took a rank novice and spent 1 hour with them--- your guy/gal wouldn't know which end was up (sweating degrees) and my guy/gal would be in danger of pocketing balls. :)
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A more reasonable approach might be to say is that like many things in pool, these techniques work well for some people but not for others. Everybody has to find their own way, and for those with the right particular skill set, angle estimation may be the best way for them.
 
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Dead Crab said:
A more reasonable approach might be to say is that like many things in pool, these techniques work well for some people but not for others. Everybody has to find their own way, and for those with the right particular skill set, angle estimation may be the best way for them.
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Most top pool players couldn't spell elephant --- and I'd spot them the PHANT --- let alone figuring arctan's of certain shots. It's novel and cute - yes - but practical - no.
 
SpiderWebComm said:
Most top pool players couldn't spell elephant --- and I'd spot them the PHANT --- let alone figuring arctan's of certain shots. It's novel and cute - yes - but practical - no.
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I respectfully disagree. I really don't care if the pros use it or not. What is important is whether it helps me to be the best player that I can be within the constraints of the time that I have to put into the game.

Sorry you don't have the knack for it.
 
Dead Crab said:
I respectfully disagree. I really don't care if the pros use it or not. What is important is whether it helps me to be the best player that I can be within the constraints of the time that I have to put into the game.

Sorry you don't have the knack for it.
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I don't have the knack for it because it's not required :) But don't mind me-- carry on....carry on.
 
Jeff G. Martin said:
I don't see how learning the angles is a waste of time, even if you shoot strictly by feel. It seems logical to me that the more information you know about a particular shot, the more it will help you. It might not help you every time, but that one time might help you significantly.
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Do you have a formula for calculating a left turn at a traffic signal? If you don't- why not? Couldn't it be very useful for beginning drivers?
 
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