Simple Squirt Test

[Patrick Johnson]

Here's a very simple way to find your shaft's Pivot Length.

1. Place any ball on the center spot of your table - this is your "object ball". Using a striped ball as your "cue ball" (with the stripe vertical and the stripe's edge pointed at the OB's edge as shown below), line up a straight shot for a corner pocket.

2. To start, separate the two balls by a measured distance that you guess is your shaft's Pivot Length minus 1 inch (so if you think your shaft might have a Pivot Length of 12", separate the balls by 11" to start).

3. Offset your tip so that it contacts the CB on the edge of the CB's stripe and the cue and the edge of the stripe are both aimed at the edge of the OB.

4. Stroke straight through the edge of the CB's stripe directly at the OB's edge - shoot the shot hard (without sacrificing accuracy) to eliminate swerve.

5. You'll miss the shot at first - that's a normal part of the test. When you miss, change the distance a measured amount and try again, aiming the cue and the edge of the CB's stripe at the OB's edge as before. If you got too much squirt, make the distance smaller. If you got too little squirt, make the distance greater.

6. When the shot goes in and the CB spins in place (more or less), the distance between the balls for that shot + 1 1/8" is your shaft's Pivot Length.

NOTE:
The Simple Squirt Test is like the "aim-and-pivot" squirt test except that it measures the Pivot Length for the actual tip/CB contact point rather than for the "center of shaft" offset. This makes the results more accurate and consistent than the aim-and-pivot results, but it means you have to add a small step when using the Pivot Length for applying aim-and-pivot ("backhhand") english: after pivoting the cue so the shaft's centerline points at the desired offset point, shift the stick slightly parallel so you'll actually hit the desired offset point with the tip.

pj
chgo

[THANKS TO JAL FOR VALUABLE INPUT.]

 

[Graciocues]

I can't wait to use your idea. I usually play at the same poolhall, the hit will be consistant. This is another way to test hit my new cues. Thanks for the new idea.
Scott

 

[Flex]

Pat,

When you line up the shot, are you lining up a straight-in shot, or a cut shot?

Also, are you using point-and-pivot when shooting, that is, backhand english? Or just offsetting the aim line?

Flex

 

[JoeyA]

Pat,

When you line up the shot, are you lining up a straight-in shot, or a cut shot?

Also, are you using point-and-pivot when shooting, that is, backhand english? Or just offsetting the aim line?

Flex

I was wondering the same thing until I thought about the cue ball needing to stay in place "spinning", after the shot. It is a straight in shot, not a cut shot. The English has to be applied pivoting the back hand or it would be parallel English. I don't thing the picture illustrates that either.
JoeyA

 

[Flex]

I was wondering the same thing until I thought about the cue ball needing to stay in place "spinning", after the shot. It is a straight in shot, not a cut shot. The English has to be applied pivoting the back hand or it would be parallel English. I don't thing the picture illustrates that either.
JoeyA

Pivoting vs parallel will definitely change the aim and contact points. I'm sure Pat will be able to clear this up.

Flex

 

[Patrick Johnson]

JoeyA:
It is a straight in shot, not a cut shot.

Yes, it's a straight-in shot, as all squirt test shots are. The picture doesn't show the "shot line", which would be through the line-of-centers of the two balls. I didn't want to confuse the "aim line", since that's the main point of the post.

The English has to be applied pivoting the back hand or it would be parallel English. I don't thing the picture illustrates that either.

The cue is angled from the shot line as normal when adjusting for squirt. For this test the amount of adjustment is set by the distance between the balls and the aim remains the same (edge of stripe to edge of OB), so neither "pivoting" nor "parallel" (whatever that is) is used.

pj
chgo

 

[Patrick Johnson]

Flex:
Pivoting vs parallel will definitely change the aim and contact points. I'm sure Pat will be able to clear this up.

Any squirt adjustment must hit the same contact point, so whatever two methods you're referring to, one of them is wrong.

Regardless, neither of them is used in this test, since the aim is always the same and only the distance between the balls is changed to fine-tune the adjustment for squirt. [Note: This doesn't represent the way you'd adjust for squirt on a real shot. It's only the way you test for squirt using this simplified method.]

pj
chgo

 

[Flex]

Any squirt adjustment must hit the same contact point, so whatever two methods you're referring to, one of them is wrong.

Regardless, neither of them is used in this test, since the aim is always the same and only the distance between the balls is changed to fine-tune the adjustment for squirt. [Note: This doesn't represent the way you'd adjust for squirt on a real shot. It's only the way you test for squirt using this simplified method.]

pj
chgo

This doesn't sound like a test with any real utility then...

FWIW, there are very few shots that I ever take when shooting with english where I'm positively eliminating any swerve whatsoever. To do that on a shot that is more than a couple of diamonds away would require really cranking out a power -- I'd almost say a "break" shot --. Those scenarios come up quite infrequently, and are of very limited use.

Actually, what I'm really interested in is a shooting, not aiming, system.

That's where all this techie stuff gets traction, IMHO.

Flex

 

[Patrick Johnson]

This doesn't sound like a test with any real utility then...

It does everything any other squirt test does - it shows where your shaft's pivot point is so you can use the pivot method of squirt adjustment, which also gives you the ability to compare your cue's squirt with others. What else do you want from a squirt test?

FWIW, there are very few shots that I ever take when shooting with english where I'm positively eliminating any swerve whatsoever. To do that on a shot that is more than a couple of diamonds away would require really cranking out a power -- I'd almost say a "break" shot --. Those scenarios come up quite infrequently, and are of very limited use.

This squirt test is just like any other squirt test (except easier to do) - it has nothing to do with measuring or eliminating swerve. That test hasn't been invented; feel free to take a shot at it.

Actually, what I'm really interested in is a shooting, not aiming, system

That's where all this techie stuff gets traction, IMHO.

"All this techie stuff" gets traction when it produces a "shooting system"? In that case, maybe you should explain what a shooting system is.

pj
chgo

 

[renard]

So after you pee in the bottle; how long till the results come back?

 

[Flex]

"All this techie stuff" gets traction when it produces a "shooting system"? In that case, maybe you should explain what a shooting system is.

pj
chgo

A shooting system will take into account not only the aiming part of the process, but also compensation for the squirt produced depending on english used (if any), swerve of the cue ball while traveling from where it is shot until contacting the object ball, as well as throw on the object ball produced by a combination of factors including the stroke used, the power of the shot (speed of cue ball when contacting the object ball). One also shouldn't forget to make any adjustments based on visual perceptions of angles and so on that are not accurate.

Complicated? You betcha...

Can I explain how all those variables interact? No chance.

The pivot point for shafts that is calculated by your method or the one used by Platinum Billiards in their tests only gives the most elementary basis for compensating.

It's useful in general terms, no doubt. But it's only a beginning.

Cheers.

Flex

 

[ribdoner]

A shooting system will take into account not only the aiming part of the process, but also compensation for the squirt produced depending on english used (if any), swerve of the cue ball while traveling from where it is shot until contacting the object ball, as well as throw on the object ball produced by a combination of factors including the stroke used, the power of the shot (speed of cue ball when contacting the object ball). One also shouldn't forget to make any adjustments based on visual perceptions of angles and so on that are not accurate.

Complicated? You betcha...

Can I explain how all those variables interact? No chance.

The pivot point for shafts that is calculated by your method or the one used by Platinum Billiards in their tests only gives the most elementary basis for compensating.

It's useful in general terms, no doubt. But it's only a beginning.

Cheers.

Flex

AHHHHHH, but the CHAMPIONS can

 

[Flex]

AHHHHHH, but the CHAMPIONS can

Can I explain it? Of course I can, to a certain extent. However, to put it in writing on a forum like this one is begging for punishment.

Can it be shown, on a pooltable? Yes, it can.

Does that mean that someone hearing an explanation and watching it executed will be able to do the same thing? Of course not.

It's one thing to explain how to do something and can be quite another to make it happen.

As for me attempting to put all those variables together and explain how to shoot a shot, pretty complicated stuff.

Oh, BTW, I forgot to mention how humidity in the pool playing environment can screw up the best shots that shortly before went down flawlessly.

How does one explain compensating for that sort of thing?

My point in all this is to highlight the role of playing by feel.

Flex

 

[Flex]

AHHHHHH, but the CHAMPIONS can

Which CHAMPIONS are you talking about, and do they give lessons?

 

[Patrick Johnson]

A shooting system will take into account not only the aiming part of the process, but also compensation for the squirt produced depending on english used (if any), swerve of the cue ball while traveling from where it is shot until contacting the object ball, as well as throw on the object ball produced by a combination of factors including the stroke used, the power of the shot (speed of cue ball when contacting the object ball). One also shouldn't forget to make any adjustments based on visual perceptions of angles and so on that are not accurate.

LOL. If you're waiting on "all this techie stuff" to produce a "system" that does all this before you'll consider it useful to you, you've got a long wait coming. Why not just get a robot to shoot for you?

pj
chgo

 

[Patrick Johnson]

Flex:
Can I explain how all those variables interact? No chance.

ribdonor:
AHHHHHH, but the CHAMPIONS can

Actually, anybody can explain how all these things affect shots - we do it all the time right here. The hard part is figuring how much of each effect for any particular shot.

pj
chgo

 

[Patrick Johnson]

I can't wait to use your idea. I usually play at the same poolhall, the hit will be consistant. This is another way to test hit my new cues. Thanks for the new idea.
Scott

Are you a cuemaker? Have you considered marking your shafts with a ring around them where the Pivot Point is? Of course, you'd have to be pretty sure of your measurement, but that would be a great feature (especially for BHE users) and would set you apart from other cuemakers.

pj
chgo

 

[Jal]

Here's a very simple way to find your shaft's squirt Pivot Length (the distance from your tip that you want your bridge to be for Backhand English):

1. Place any ball on the center spot of your table - this is your "object ball". Using a striped ball as your "cue ball" (with the stripe vertical and lined up with the shot), line up a shot for a corner pocket with the two balls separated by about the length you guess is your shaft's Pivot Length (a typical guess might be 12 inches).

2. Offset your tip so that you contact the "cue ball" right on the edge of the vertical stripe. This will be 17/32 of an inch (1/2 + 1/32 inch) from centerball, just about halfway from center to the ball's edge (using Centennial balls).

4. Aim the edge of the stripe at the edge of your "object ball". Stroke straight at the edge of your object ball. Shoot the shot hard to eliminate swerve.

5. If you miss the shot change the distance and try again. If you got too much squirt, make the distance smaller. If you got too little squirt, make the distance greater.

6. When the shot goes in and the "cue ball" spins in place, the distance between the balls before you shot is your shaft's Pivot Length.

[TIP: If you miscue hitting on the edge of the stripe, hit a little closer to center on the "cue ball" and aim the same distance inside the edge of the OB.]

In case anybody's interested, two of my cues tested as follows:

Off-the-shelf Joss with 13mm tip: 10.5-11"
Custom hollow-tipped shaft with 10mm tip: 23-23.5"

I've compared my custom shaft to an OB-1 shaft and the OB-1 produced slightly more squirt. I guess it would test at about 20".

pj
chgo

You may want to re-think this method over a bit. Either that or I may want to re-think my math. But I have checked it (my math) and am not aware of an error.

Your original diagram and explanation yields a fairly severe underestimate of a cue's true pivot point distance from the tip. The current version produces a fairly severe overestimate. There are slightly different ways to define the pivot point, but I'm going by the one which has it as follows: line up for centerball, pivot about the PP to strike at some offset...the cueball will then head in the direction in which you were lined up for centerball.

The above assumes that throw and post-impact swerve aren't mucking things up. They will actually provide some correction to your first method, but...

A better way is to aim the center of the shaft at the (1/2)R offset (instead of making this the actual contact point as per your first diagram), with the object ball still displaced (1/2)R from a line going through the center of the cueball in the aim direction (as you had it). Then, upon a successful pot, take the pivot point distance as the distance between the ball's edges (as you had it, more or less), but add R to this.

It would take some diagrams and math to show exactly what I mean, but maybe you'll have a go at it. It could be that I'm full of it.

To all but eliminate throw, the contact area on the OB should be wet. And I would recommend judging a full hit not by what the cueball does afterwards (ie, spinning in place), but by the OB going straight along the pre-shot line of centers. Since your method is based on pocketing the OB primarily, this is built into it. Ignoring the cueball prevents post-collision swerve from skewing one's judgement.

Jim

 

[Patrick Johnson]

It could be that I'm full of it.

I doubt that, Jim. But even if you're half full of it, that's better than half empty, right?

I appreciate you taking a look at this, and off the top of my head I think you have a point, but I can't give it the thought it needs until after work tonight. I'll get back to you then.

pj
chgo

 

[Flex]

LOL. If you're waiting on "all this techie stuff" to produce a "system" that does all this before you'll consider it useful to you, you've got a long wait coming. Why not just get a robot to shoot for you?

pj
chgo

I'm not waiting on the techie stuff to actually produce a system. It can be very valuable. But I also think there's a great danger or temptation to succumb to paralysis by analysis. Too much techie stuff can produce that.

Understanding the physics or mechanics of pool is one thing, and it can go a long way to helping understand how to play better.

However, my overall point is that when a player is presented with a particular set of balls, with their imperfections, with chalk or dirt or wax on them, with a particular cue ball, whether it be a red circle or blue circle or measles or generic or whatever, on a particular table with cloth that may be slow or medium or fast, under conditions that may include a dirty, chalky table, and humidity that varies over a relatively short period of time, as may easily occur in a tournament room such as the one at Chris's that can go from chilly and relatively dry to hot and plenty humid in less than an hour or so, that when confronted with circumstances such as these, that any system will be fraught with problems and limitations. IMHO, when presented with almost infinitely variable conditions, a player needs to have an acute sense of changes that can occur simply by going from one table to another in the same room and be able to adapt. This adaptation will not be robotic, it needs to be sensed and felt. A good memory certainly helps. For instance, knowing how to shoot three rail kicks is great, and knowing different systems is important. But switch from one table to another and if one table is just 1/2 diamond short or long, if a player doesn't know that and adjust to it, his 3 rail kicks may be close but not on. Adaptation is the key.

One very good player at Chris's during the warm up period before the matches in the tournament room told me he tries to play on all the tables before the tournament begins. Why? Although he knows the tables well, each table will have a different ball set. The cue balls at Chris's vary quite a bit. Even though they change or buy new sets every year or so, at least that's what they've told me, sometimes people swap stuff on them, witness generic balls in the middle of Centennial sets, and cue balls that come from who knows where.

Robotics won't resolve the problems I've outlined. However, a fine sense of actual playing conditions and adaptation to the same will go a long way to helping things along.

Flex