squirt, swerve, and throw effects summary

[dr_dave]

pivot point aim compensation

After reading that article, it seems this point can be summed up by saying as long as your bridge is at the pivot point you'll cancel swerve.

Aim-and-pivot methods (e.g., BHE and/or FHE) are for squirt (not swerve) compensation. The "natural pivot length" of a cue corresponds to squirt correction only. Compensating one's aim for swerve is not so simple. For more info, see the answer to the 2nd question here:

http://billiards.colostate.edu/threads/cue.html#pivot

Regards,
Dave

 

[av84fun]

Jim,
I use Grady's "click" method - so each click/tip adjustment is to the edge of the tip (each click is about a half/tip width; 4 is about the maximum without miscuing). I call these adjustment "tips", but probably incorrectly so...they are really half-tip width adjustments. Sorry for the confusion.

I didn't find any difference between my Predator and my OB-1 as far as allowing for deflection. I never tested it as you do; but if I power it (minimizing swerve), I would guess that both the Predator and OB-1 squirt more than an inch; more like 2 inches. Maybe the shaft length is an issue (mine are all 1 inch longer than standard), or maybe you are hitting it like a little girl and getting some swerve (since Dave says it doesn't squirt more with a harder hit).

What I've been thinking the past hour, is that maybe I'm judging this on close shots where the squirt is not completed before the cue ball gets to the object ball.

LOL...Next time we're together at a place where someone has a radar gun, let's bet $100 per mph on a break shot and we'll see who the "girlieman" is.

(-:

Thanks for clearing up the "tips of english" matter.

What I've been thinking the past hour, is that maybe I'm judging this on close shots where the squirt is not completed before the cue ball gets to the object ball

Now you have me confused again. If you are estimating the squirt offset on close shots, it should be a SMALLER number of inches, not a higher one.

While the squirt ANGLE doesn't change with speed the variation vs. the target is a function of DISTANCE not ANGLE.

Try my method a couple of times with an OB frozen to the center of the head rail and the CB at various distances. Getting as far away as the 1st diamond string at the foot of the table would produce about the maximum variation...or even better, shoot diagonally from corner to corner.

Since you would be aiming at the center of a 2.25 in. sphere, then slightly more than a 2.25" variation would result in missing the OB entirely.

Unless there is something about your cue (maybe the added length is the culprit) then I can't imagine anyone missing the entire ball.

My GUESS is that you are getting much less squirt than you think due to some issue with the way you attempt to measure it. Using the balls as described provides a pretty fool proof way to measure...unless the shooter aims incorrectly in the first place in which case...as they say in the computer world...garbage in, garbage out.

I would be interested to hear your results.

Regards,
Jim

 

[Maniac]

I thought this was a thread about pleasuring oneself while driving a convertible.
I was gonna share an experience I had in my TR 3 convertible. Sorry, wrong thread.
Purdman

I'm sure glad I didn't have a mouthful of Pepsi when I read the first sentence of this post! It probably would've ended up shooting out of my nostrils. That's funnier than $hit Purdman!!!

Maniac

 

[Williebetmore]

LOL...Next time we're together at a place where someone has a radar gun, let's bet $100 per mph on a break shot and we'll see who the "girlieman" is.

(-:

My GUESS is that you are getting much less squirt than you think due to some issue with the way you attempt to measure it.

I would be interested to hear your results.

Regards,
Jim

Jim,
I will definitely pass on the breaking contest...the only break I've practiced is my straight pool break, I suspect my 2 mph break could easily be beaten.

You are correct on the squirt issue. I've only ever measured how much I need to adjust my cue at the cue ball to make the shot; never tried your way. Today I set it up, and even with the most powerful shot, the cueball still struck the object ball with about a half-ball hit; a lot less than I estimated.

 

[av84fun]

Jim,
I will definitely pass on the breaking contest...the only break I've practiced is my straight pool break, I suspect my 2 mph break could easily be beaten.

You are correct on the squirt issue. I've only ever measured how much I need to adjust my cue at the cue ball to make the shot; never tried your way. Today I set it up, and even with the most powerful shot, the cueball still struck the object ball with about a half-ball hit; a lot less than I estimated.

I'll send you my bill!

LOL

 

[iralee]

Hello Dr. Dave, I like your high speed videos on billiards and I hope that you continue to do more billiard physics experiments.

I'm wondering what studies you have done to make this conclusion:

Squirt does not depend on shot speed.

Is there an article, video or experiment you can refer me to? Thanks.

 

[enzo]

is it just me, or do 10 and 12 contradict one another. i definitely agree with 12. maybe a misunderstanding of the term sliding on my part.

nice post dave!

 

[Purdman]

I'm sure glad I didn't have a mouthful of Pepsi when I read the first sentence of this post! It probably would've ended up shooting out of my nostrils. That's funnier than $hit Purdman!!!

Maniac

I'm sorry man, I been at work all day and now I have tears in my eyes, THANKS.
Purdman

 

[Purdman]

I'm sure glad I didn't have a mouthful of Pepsi when I read the first sentence of this post! It probably would've ended up shooting out of my nostrils. That's funnier than $hit Purdman!!!

Maniac

I know man, the squirt and accompanying erotic pleasure, the swerving car while in the moment, and tossing the rag out of the car when done. Reminds me of high school whenever I had a bag of really good weed and a chick with me. That gal was freaking out.
Purdman

 

[Bob Jewett]

is it just me, or do 10 and 12 contradict one another. i definitely agree with 12. maybe a misunderstanding of the term sliding on my part.

nice post dave!

Sliding means that the cue ball is not rolling smoothly on the cloth. It might have draw or "center ball" or partial rolling forward, but in the context of swerve, those are all considered sliding. On a draw shot the length of the table, the cue ball might still be sliding at the far end. For a follow shot at the same speed, the cue ball will be rolling smoothly much sooner. This means that the swerve for a follow shot will finish earlier (in the path and in time) than the swerve for a draw shot.

 

[dr_dave]

follow vs. draw swerve

Sliding means that the cue ball is not rolling smoothly on the cloth. It might have draw or "center ball" or partial rolling forward, but in the context of swerve, those are all considered sliding. On a draw shot the length of the table, the cue ball might still be sliding at the far end. For a follow shot at the same speed, the cue ball will be rolling smoothly much sooner. This means that the swerve for a follow shot will finish earlier (in the path and in time) than the swerve for a draw shot.

Bob,

Thanks for answering. I had a very busy day. As always, excellent answer!

FYI to enzo and others, I have good illustrations and explanations of this in my October '07 and March '08 articles.

Regards,
Dave

 

[Ant812]

EXCELLENT POST. im still trying to to take in your march article, it goes against everything i have believed in the past. on the table if i hit a long shot with sidespin with speed the same way i hit it with less speed i always miss it on the squirt side. i have always tried to avoid those type of shots but since reading the article, i have decided its something i need to learn. i have to say its one of the hardest shots i have ever tried to learn.

 

[dr_dave]

pool is hard

EXCELLENT POST. im still trying to to take in your march article, it goes against everything i have believed in the past. on the table if i hit a long shot with sidespin with speed the same way i hit it with less speed i always miss it on the squirt side. i have always tried to avoid those type of shots but since reading the article, i have decided its something i need to learn. i have to say its one of the hardest shots i have ever tried to learn.

There is no doubt about it ... long shots with English are just tough. Many things must be accounted for: squirt amount (which varies from one cue to another), cue elevation, amount and type of English, shot speed, shot distance, ball and cloth conditions, etc. This is one of the things that makes high-level pool so hard.

Regards,
Dave