Paging Dr. Dave or other qualified applicants - physics question.

[CreeDo]

This one has been subconsciously bugging me.

Recently, a thread came up about making stop shots, and some people said they always hit low, rather than try for a perfect centerball.

Then in another thread CJ mentioned his touch of inside trick, and it sounds like the thrust of it is... he prefers to hit with inside knowing for sure what spin he's putting on the ball, rather than try to hit center and risk some slight stroking error causing unintended sidespin in either direction.

So my question is, does a slight error in tip placement affect the cut angle differently, depending on whether you started out with center ball vs. starting out with sidespin?

For example, let's say you plan on using outside and you accidentally hit, I dunno, 3 mm further outside than intended. As a result the ball overcut exactly 0.5 degrees (maybe not a realistic number).

If you had started aiming at center ball and then gone 3 mm to the outside, would you still overcut exactly 0.5 degrees? Or would it have overcut a different amount?

If it's different, is there an offset amount where slight errors matter the least, and another tip offset amount where they matter the most?

I guess it would help to define a few variables.
Let's say lag speed, 40 degrees, CB 3 feet from the OB.

 

[Bob Jewett]

... For example, let's say you plan on using outside and you accidentally hit, I dunno, 3 mm further outside than intended. As a result the ball overcut exactly 0.5 degrees (maybe not a realistic number). ...

If you have chosen the "right" bridge length for the shot and the right bridge position (left-to-right) for the shot at hand, some small left-to-right error in tip contact won't make any difference to the cut angle. That's because it's possible for the change in speed, spin and direction of the cue ball to be cancelled by the resulting changes in squirt, swerve and throw. Depending on the various factors it is also possible for a small error of the tip hitting too far to the right to cause either a cut error to the left or right.

So, your question has no certain answer until more data is available. For more info, see the column on "Forced Accuracy" from 2011 in http://www.sfbilliards.com/articles/BD_articles.html

This cancellation business is the fundamental reason that backhand english works. Understanding the details of the cancellation lets you understand the limitations of backhand english.

 

[CJ Wiley]

Just wanted to clarify that for the "sake of science."

This one has been subconsciously bugging me.

Recently, a thread came up about making stop shots, and some people said they always hit low, rather than try for a perfect centerball.

Then in another thread CJ mentioned his touch of inside trick, and it sounds like the thrust of it is... he prefers to hit with inside knowing for sure what spin he's putting on the ball, rather than try to hit center and risk some slight stroking error causing unintended sidespin in either direction.

So my question is, does a slight error in tip placement affect the cut angle differently, depending on whether you started out with center ball vs. starting out with sidespin?

For example, let's say you plan on using outside and you accidentally hit, I dunno, 3 mm further outside than intended. As a result the ball overcut exactly 0.5 degrees (maybe not a realistic number).

If you had started aiming at center ball and then gone 3 mm to the outside, would you still overcut exactly 0.5 degrees? Or would it have overcut a different amount?

If it's different, is there an offset amount where slight errors matter the least, and another tip offset amount where they matter the most?

I guess it would help to define a few variables.
Let's say lag speed, 40 degrees, CB 3 feet from the OB.

Just for accuracy I'm not spinning the cue ball with inside. I'm favoring the inside so if I'm slightly off on one side I hit center, if I'm off on the other side I hit it slightly more inside. I'm wanting to control the speed, shot angle and cue ball target and make them consistent.

This is only possible by favoring one side of the cue ball. The inside part is where the cue ball aligns to the contact point so it makes sense to use the inside, not the outside portion {of the cue ball}.

I'm guarding against the possibility of hitting it off center in TWO different ways (then I'd be guessing). There's much more to it, but this covers the clarification involving the statement in your thread.

The name of the game at the upper levels of pool is REDUCING unnecessary calculations and guesswork. Just wanted to clarify that for the "sake of science."

 

[Patrick Johnson]

CreeDo:
...does a slight error in tip placement affect the cut angle differently, depending on whether you started out with center ball vs. starting out with sidespin?

No, if your stroke is off to the left or right it doesn't matter if you're trying to hit center ball or deliberately hitting to one side of center - you'll miss by the same amount and in the same direction either way. In other words, TOI does not eliminate stroke errors in one direction or increase the pocket margin of error.

This was pointed out when this claim was first made, and has been pointed out multiple times since then.

pj
chgo

 

[Ralph Kramden]

No, if your stroke is off to the left or right it doesn't matter if you're trying to hit center ball or deliberately hitting to one side of center - you'll miss by the same amount and in the same direction either way. In other words, TOI does not eliminate stroke errors in one direction or increase the pocket margin of error.

This was pointed out when this claim was first made, and has been pointed out multiple times since then.

pj
chgo

PJ...

I'm not saying you're wrong here... but I think CJ is correct. If you aim exactly CB center ball and miss the hitting the center on either side, the CB will "squirt" slightly to either side, opposite the cue tip contact.

If intensionally playing slightly toward the side of CB center ball, the CB will always squirt slightly to the intended side. If you miss toward the CB center line it will go straight to where it was aimed.

With just a touch of inside, the CIT is minimized. Aiming toward the side of the pocket, the OB will either go into the side of the pocket, or be thrown toward the pocket centerline.

That is my conception of what CJ is saying. Carl

 

[Patrick Johnson]

PJ...

I'm not saying you're wrong here... but I think CJ is correct.

One of us must be wrong.

If you aim exactly CB center ball and miss the hitting the center on either side, the CB will "squirt" slightly to either side, opposite the cue tip contact.

If intensionally playing slightly toward the side of CB center ball, the CB will always squirt slightly to the intended side. If you miss toward the CB center line it will go straight to where it was aimed.

With just a touch of inside, the CIT is minimized. Aiming toward the side of the pocket, the OB will either go into the side of the pocket, or be thrown toward the pocket centerline.

That is my conception of what CJ is saying. Carl

That is what CJ is saying. It's mistaken.

pj
chgo

 

[dr_dave]

So my question is, does a slight error in tip placement affect the cut angle differently, depending on whether you started out with center ball vs. starting out with sidespin?

If you have chosen the "right" bridge length for the shot and the right bridge position (left-to-right) for the shot at hand, some small left-to-right error in tip contact won't make any difference to the cut angle. That's because it's possible for the change in speed, spin and direction of the cue ball to be cancelled by the resulting changes in squirt, swerve and throw. Depending on the various factors it is also possible for a small error of the tip hitting too far to the right to cause either a cut error to the left or right.

No, if your stroke is off to the left or right it doesn't matter if you're trying to hit center ball or deliberately hitting to one side of center - you'll miss by the same amount and in the same direction either way. In other words, TOI does not eliminate stroke errors in one direction or increase the pocket margin of error.

For what it's worth, I agree with both Bob and PJ.

When one hits left or right of the CB centerline, squirt, swerve, and throw can affect the shot, and they will do so differently based on shot speed, shot distance, cut angle, cue elevation, shaft endmass, cloth conditions, and whether the CB has stun (no topspin or bottom spin) or not.

As Bob points out, for a given shot, there is a bridge length that will make all of the effects cancel, but one must be very good at judging all of this stuff to choose the bridge length and/or cue elevation and/or shot speed to make this work for every shot.

For more info, illustrations, instructional articles, and video demos related to all of these topics, see:

squirt, swerve, and throw effects
aim compensation for squirt, swerve, and throw
back-hand english (BHE) and front-hand english (FHE)
cue natural pivot length​

Having said all of this, inside english (either a touch or more) does offer some benefits. For more info, see:

inside english resource page​

Regards,
Dave

 

[TATE]

This one has been subconsciously bugging me.

Recently, a thread came up about making stop shots, and some people said they always hit low, rather than try for a perfect centerball.

Then in another thread CJ mentioned his touch of inside trick, and it sounds like the thrust of it is... he prefers to hit with inside knowing for sure what spin he's putting on the ball, rather than try to hit center and risk some slight stroking error causing unintended sidespin in either direction.

So my question is, does a slight error in tip placement affect the cut angle differently, depending on whether you started out with center ball vs. starting out with sidespin?

For example, let's say you plan on using outside and you accidentally hit, I dunno, 3 mm further outside than intended. As a result the ball overcut exactly 0.5 degrees (maybe not a realistic number).

If you had started aiming at center ball and then gone 3 mm to the outside, would you still overcut exactly 0.5 degrees? Or would it have overcut a different amount?

If it's different, is there an offset amount where slight errors matter the least, and another tip offset amount where they matter the most?

I guess it would help to define a few variables.
Let's say lag speed, 40 degrees, CB 3 feet from the OB.

Hate to spoil the party, but here are some "street" results. We had an instructor who was teaching a cueing technique involving inside, adjusting aim for squirt and squirting the ball over on every shot. With english, he was teaching a last minute tip movement.

To make a long story short, his students were so freaking confused their games went down about 30% for a year or two before they realized he was a charlatan and gave up on his dumb ideas.

Now I'm not saying CJ is doing this, since he emphasized only slight off center cueing. This guy was squirting the cue ball a lot!

It's possible to play well cueing off to the side on most shots. It's also possible to play well staying in the center on most shots. Which is less complicated?

 

[alphadog]

This one has been subconsciously bugging me.

Recently, a thread came up about making stop shots, and some people said they always hit low, rather than try for a perfect centerball.

Then in another thread CJ mentioned his touch of inside trick, and it sounds like the thrust of it is... he prefers to hit with inside knowing for sure what spin he's putting on the ball, rather than try to hit center and risk some slight stroking error causing unintended sidespin in either direction.

So my question is, does a slight error in tip placement affect the cut angle differently, depending on whether you started out with center ball vs. starting out with sidespin?

For example, let's say you plan on using outside and you accidentally hit, I dunno, 3 mm further outside than intended. As a result the ball overcut exactly 0.5 degrees (maybe not a realistic number).

If you had started aiming at center ball and then gone 3 mm to the outside, would you still overcut exactly 0.5 degrees? Or would it have overcut a different amount?

If it's different, is there an offset amount where slight errors matter the least, and another tip offset amount where they matter the most?

I guess it would help to define a few variables.
Let's say lag speed, 40 degrees, CB 3 feet from the OB.

Don't believe you intended to pose a trick ? but-If a shot is straight in-
there would not be ....inside,or outside. Right?

 

[Ralph Kramden]

Just my own 2 cents on a Touch of Inside (TOI).

I was reading CJ's blogs and tried some of the things he was suggesting.

Somewhere along the line he said to try hitting balls with a TOI for three hours. Just TOI on every shot.
Thought this to be somewhat nuts... but I tried it. It took less than that for me to be convinced TOI works.

You can't play that way, using it on EVERY shot... but I'm convinced pocketing is easier. My table has 4 1/4 corners & 4 3/4 sides... Very tight.
Shots go in with a lot more authority using a TOI.

I was taught how to play almost 60 years ago. The room owner told me that if I used 1 tip of side english on the CB to aim 1 tip further on the same side of
the OB. I've aimed this way for as long as dinosaurs roamed. Not always quite the same distance as I was taught... but usually close, depending on the shot. ( I'm much older than 60 now... sad to say)

I've shyed away from inside english because of CIT. Trying it CJ's way is a different animal tho'. I'd say give it a try... 3 hours TOI only.

Now for one more thought on TOI. Check out CJ's blogs. His web site has a few videos that are interesting. He's playing these guys using a TOI.
How can you argue with someone who can beat Mike Sigel, Buddy Hall and Earl Strickland... using a TOI. I'm not even qualified to shine their shoes.

 

[oshua86]

Don't believe you intended to pose a trick ? but-If a shot is straight in-
there would not be ....inside,or outside. Right?

Yes there is, even if cue ball and object ball are perfectly in line, the pocket is bigger than the object ball, the side of the pocket that you aim that's inside.

 

[oshua86]

Just my own 2 cents on a Touch of Inside (TOI).

I was reading CJ's blogs and tried some of the things he was suggesting.

Somewhere along the line he said to try hitting balls with a TOI for three hours. Just TOI on every shot.
Thought this to be somewhat nuts... but I tried it. It took less than that for me to be convinced TOI works.

You can't play that way, using it on EVERY shot... but I'm convinced pocketing is easier. My table has 4 1/4 corners & 4 3/4 sides... Very tight.
Shots go in with a lot more authority using a TOI.

I was taught how to play almost 60 years ago. The room owner told me that if I used 1 tip of side english on the CB to aim 1 tip further on the same side of
the OB. I've aimed this way for as long as dinosaurs roamed. Not always quite the same distance as I was taught... but usually close, depending on the shot.

I've shyed away from inside english because of CIT. Trying it CJ's way is a different animal tho'. I'd say give it a try... 3 hours TOI only.

Now for one more thought on TOI. Check out CJ's blogs. His web site has a few videos that are interesting. He's playing these guys using a TOI.
How can you argue with someone who can beat Mike Sigel, Buddy Hall and Earl Strickland... using a TOI. I'm not even qualified to shine their shoes.

I just recently starting using TOI but Earl Strickland actually used to teach me that technique about a year ago when he would play with me, obviously understanding Earls logic is sometimes rather confusing, but he pretty much uses it in every shot.

 

[ENGLISH!]

Just my own 2 cents on a Touch of Inside (TOI).

I was reading CJ's blogs and tried some of the things he was suggesting.

Somewhere along the line he said to try hitting balls with a TOI for three hours. Just TOI on every shot.
Thought this to be somewhat nuts... but I tried it. It took less than that for me to be convinced TOI works.

You can't play that way, using it on EVERY shot... but I'm convinced pocketing is easier. My table has 4 1/4 corners & 4 3/4 sides... Very tight.
Shots go in with a lot more authority using a TOI.

I was taught how to play almost 60 years ago. The room owner told me that if I used 1 tip of side english on the CB to aim 1 tip further on the same side of
the OB. I've aimed this way for as long as dinosaurs roamed. Not always quite the same distance as I was taught... but usually close, depending on the shot. ( I'm much older than 60 now... sad to say)

I've shyed away from inside english because of CIT. Trying it CJ's way is a different animal tho'. I'd say give it a try... 3 hours TOI only.

Now for one more thought on TOI. Check out CJ's blogs. His web site has a few videos that are interesting. He's playing these guys using a TOI.
How can you argue with someone who can beat Mike Sigel, Buddy Hall and Earl Strickland... using a TOI. I'm not even qualified to shine their shoes.

Good post. Well stated. I'm only 59 but changing 46 yrs. of spinning the balls in is a bit difficult to change. But...if the old dog does not learn new tricks then the old dog won't be in the show. I'm working on it in between playing my individual league. After that it's three(3) weeks straight. IMHO Anyone that is opposed to it has not done it correctly for any real length of time. The bottom line is, it works, even if one does not use it ALL of the time, it is a volatile weapon.

Best Regards to You &

 

[CreeDo]

CJ, thanks for the clarification. I knew I was probably misunderstanding.

Others: I am not interested in proving CJ right or wrong, or in trying to figure out a way that I can screw up my tip placement and still get away with it.

I'm just interested to know if tip placement errors require more care for some cuts than for others. Sort of like how CIT is a bigger issue on some cuts than others.

If I knew 3mm of error causes only half degree of miss on a 45 degree cut, but potentially causes 2 degrees of miss on a nearly-straight shot, then might choose to avoid sidespin on that specific shot, or at least be extra careful about it.

Similarly, if I knew that 3mm of left and 6mm of left sent the ball roughly on the same line, whereas 3mm of left vs. centerball caused wildly different lines, I might decide to always use left on that cut.

 

[3andstop]

It was interesting to read CJ's comment on favoring a touch of inside. Just about 45 years ago, when I first starting taking the game seriously as a student of improvement, I would go down to my local pool room at least 4 or 5 times a week.

The older fellow who ran the counter would play straight pool by himself while answering the phone and checking players in or out.

He COMMONLY ran 70's or so while doing all these things in a very nonchalant manner.

I'll never forget, he got a bit out of line and had to shoot one of those long nearly straight in shots. He made it no problem, and I commented, boy there is a regular stopper for me!

He said, hit those shots with a touch of inside english, it will straighten the shot out for you.

To this day, when I'm feeling not quite so confident while I'm attempting these kinds of shots, I'll remember what he said and do just that. Very wise words IMO.

 

[Patrick Johnson]

CreeDo:
I'm just interested to know if tip placement errors require more care for some cuts than for others. Sort of like how CIT is a bigger issue on some cuts than others.

Spin-induced throw is maximized on straight or almost straight shots and is less sensitive as the cut angle gets greater. So be most careful on straight shots. This is conventional (well known) wisdom.

pj
chgo

 

[dr_dave]

... inside english (either a touch or more) does offer some benefits. For more info, see:

inside english resource page​

For convenience, here's the list of potential benefits of inside English (IE), from the resource page:

1. Some people tend to undercut shots by aiming fuller than the shot requires, and inside english will create squirt that increase the resulting cut angle slightly (although, spin-induced throw will tend to counteract this some).
2. A small amount of IE can counteract the effects of cut-induced spin on the cue ball, possibly resulting in a more natural and predictable rebound angle off a cushion.
3. IE increases throw at small cut angles, but actually reduces the amount of throw at larger cut angles.
4. The amount of throw with IE can be much more consistent than with outside english (OE) if the amount of english varies a little. In other words, the amount of throw varies more with tip placement for OE vs. IE. This might explain why some people prefer using IE on cut shots ... because they can better anticipate and adjust for the amount of throw.
5. The least amount of throw, and the most throw consistency, occurs with fast IE shots.

Regards,
Dave

 

[ENGLISH!]

Dr. Dave,

If would be so kind, could you elaborate a bit on #3?

IE increases throw because it has adds to the CIT.

How does IE reduce that throw on larger cut angles?

Thanks in advance should you choose to respond.

Regards to You &

 

[Patrick Johnson]

How does IE reduce that throw on larger cut angles?

The same way that faster shots throw less: if the surfaces rub across each other at high speed friction is reduced (like a tire peeling out on pavement).

That's also the reason that outside spin can actually increase throw on thinner cuts - if it's too little spin for perfect "gearing" english it will just slow the rubbing surfaces down and reduce the slippage.

pj
chgo

(Sorry for butting in, Dave.)

 

[Cornerman]

It was interesting to read CJ's comment on favoring a touch of inside. Just about 45 years ago, when I first starting taking the game seriously as a student of improvement, I would go down to my local pool room at least 4 or 5 times a week.

The older fellow who ran the counter would play straight pool by himself while answering the phone and checking players in or out.

He COMMONLY ran 70's or so while doing all these things in a very nonchalant manner.

I'll never forget, he got a bit out of line and had to shoot one of those long nearly straight in shots. He made it no problem, and I commented, boy there is a regular stopper for me!

He said, hit those shots with a touch of inside english, it will straighten the shot out for you.

To this day, when I'm feeling not quite so confident while I'm attempting these kinds of shots, I'll remember what he said and do just that. Very wise words IMO.

I think I just had an AHA moment!

Freddie <~~~ get me to a table!