Actual Low Deflection Testing

[dr_dave]

If your goal is to measure just the CB deflection (squirt) characteristics of a shaft, the natural pivot length is the best measurement. And to get the most accuracy for this measurement, one should use fast speed over a short distance with the cue as level as possible (ideally perfectly level, for example with a machine that doesn't need to reach over a rail). Otherwise, the results of the test will vary too much with shot speed, shot distance, cue elevation, and cloth conditions. Then people could not directly compare measured values.

For more info, see:

Rules of CB Deflection (Squirt) Testing

Again, the goal of a test should be to measure just the cue's characteristics, not how the cue produces different results at a table for different shots by different people under different conditions.

There is where I disagree a bit. For people to accurately test the shaft on how it will effect their game, they have to test it under the conditions that they play. Again, people don't hit hard for every shot. So for someone to see the squirt or deflection from a test hitting hard, thats fine and dandy but that doesn't show them how the shaft squirts on shots that they hit.

Nothing wrong with that approach if your only goal is to see how two shafts compare for you for a given stroke speed, shot distance, cloth condition, and cue elevation. But you won't be able to directly compare your experience with anybody else's experience, and if you don't hit the CB at the exact same speed with the exact same cue elevation with each shaft, your comparison might be flawed.

What a cue manufacturer should provide, and what a buyer should want to know is the natural pivot length of a shaft. Anybody could test for this, and everybody's result should be the same. And to know how two shafts might compare (without having to physically test them yourself), all you need to know is the natural pivot length for each shaft.

FYI, the natural pivot length test would not need to be done at fast speed if the cue being tested were perfectly level (e.g., on a test table with no rail to reach over). With a perfectly level cue, the natural pivot length result would be the same regardless of shot speed.

Regards,
Dave

 

[iusedtoberich]

Hi dr Dave. I wonder if placing a piece of melamine coated particleboard on top of the table bed, and then shooting the pivot length test shot on its surface, would allow a perfectly level stroke. You can buy them in shelf form at Home Depot for $10. They are very uniform in thickness, probably within 0.005” for their entire area.

I believe from reading material on squirt that table friction has no bearing on it.

Maybe even use a bridge head instead of a hand bridge for more accurate measurement of the bridge location.

Thinking out loud

 

[briankenobi]

[QUOTE="Dr_Dave]Nothing wrong with that approach if your only goal is to see how two shafts compare for you for a given stroke speed, shot distance, cloth condition, and cue elevation. [/QUOTE]

It is a nice quick example to show people the difference and how it would directly effect their game. That's what most people want. As cool as the science behind stuff is and how technical it can be, most people don't care about it. We can talk about natural pivot lengths until we are blue in the face, but if all the customer wants is a "show me how they are different so I can make a choice on which one I get" that's all the cue companies need to do. And by no means am I demeaning what you are saying. I enjoy the technical side of pool and your stuff that I have seen. But from my experience from having booths at a lot of city league tournaments and being successful at moving product at those, the best approach is the most simple one.

Just my 2 cents.

 

[dr_dave]

Hi dr Dave. I wonder if placing a piece of melamine coated particleboard on top of the table bed, and then shooting the pivot length test shot on its surface, would allow a perfectly level stroke. You can buy them in shelf form at Home Depot for $10. They are very uniform in thickness, probably within 0.005” for their entire area.

I believe from reading material on squirt that table friction has no bearing on it.

Maybe even use a bridge head instead of a hand bridge for more accurate measurement of the bridge location.

Thinking out loud

Excellent ideas, but I don't think the "that looks too much like science" crowd would like this very much.

Thanks,
Dave

 

[Patrick Johnson]

For people to accurately test the shaft on how it will effect their game, they have to test it under the conditions that they play.

Since only the amount of swerve (not squirt) changes with different shot types and styles, comparing "natural squirt" gives them all the info they need in order to judge how the two shafts will perform for all shots.

pj
chgo

 

[jburkm002]

An LD shaft produces less CB deflection than a non-LD shaft.

With less CB deflection, the amount you need to adjust your aim is less.

For more info, see advantages of LD shafts.

Regards,
Dave

Again, this is where I get confused. I totally understand the principles behind LD shafts. However I was under the impression that SAWS was kinda the counter argument to LD shafts. Where someone could aim exactly the same using sidespin, no matter what shaft they used.

 

[Patrick Johnson]

Again, this is where I get confused. I totally understand the principles behind LD shafts. However I was under the impression that SAWS was kinda the counter argument to LD shafts. Where someone could aim exactly the same using sidespin, no matter what shaft they used.

No, SAWS is just a way to make the unavoidable aim adjustments for CB deflection more deliberate and “measured”. It doesn’t eliminate the need for aim adjustments or change the amount of aim adjustment needed, or eliminate the need to PRACTICE. Even if you don’t use it, understanding it will teach you more about the subject than most players know.

I adjust for CB deflection purely “by feel”, but understanding the principles that SAWS uses makes it easier.

pj
chgo

 

[336Robin]

There is where I disagree a bit. For people to accurately test the shaft on how it will effect their game, they have to test it under the conditions that they play. Again, people don't hit hard for every shot. So for someone to see the squirt or deflection from a test hitting hard, thats fine and dandy but that doesn't show them how the shaft squirts on shots that they hit.

The test I outlined is just a basic "here's the difference between a maple shaft and a LD shaft." It is something easy that people can see and relate too.



Most of them aren't but they can be. You just have to look at the testing conditions to see if it really makes sense. For example, the artificial sweetener tests. You will see studies that say artificial sweeteners cause cancer. What people won't talk about is are the testing conditions. The amount that the lab rats ingested that gave them cancer vs the amount people normally take in is the difference between the high of a person vs the height of the empire state building. The study was correct under the conditions that it was tested. However, those conditions aren't real word. That was the basis of my comment. Test real word conditions. See how shafts react under normal playing conditions vs testing it hitting really hard.

In my book The Flight of the Cue Ball I conducted tests on 3 basic shafts and I used the basic same step as Dr. Dave did in his online YouTube squirt testing to shooting them 7 diamonds away from the rail. I used the same kind of tips on the shafts. They were all Triangles.

I tested a 13mm shaft with 8 in Factory Taper with factory ferrules and Ivory Ferrules

Then my normal playing shaft 12.80 mm 15 in Pro Taper with factory ferrules.
I used another cue same Taper that was 12.75 with Ivory to test against this shaft and the squirt was equal to and sometimes greater.

Then I tested several LD's as people would let me borrow them and use them awhile. All in all they are very similar and squirt less than my normal playing shafts.

The LD's at short range were almost indistinguishable between each other for squirt allowances but in general they were less than my normal playing shaft giving me more confidence on those shots when I needed to spin the cue ball. I viewed this as a plus and after that book was complete I changed to the original Jacoby Hybrid Shaft. I use Elkmaster Tips and like the hit. However there is an element of feel that is missing unless your LD shaft is a bit less than 13mm. I attribute this to being used to the flex of a regular maple shaft and I've gotten used to no flex. I have one shaft a bit less than 13mm and its my favorite.

I published a total squirt measurement for those shafts and by using division was able to arrive at a formula that one could use to plot their hold/adjustment for the various diamonds of distance their cue ball is from the object ball.

This works but is a bit technical and in my new updated version I found an easier way to apply the technique. I aim differently than most people but my aiming perceptions are in my opinion correct in that they point to the pocket. If you go by my aiming perceptions, note your distance from the object ball. Have practiced a shot or two using the side spin selection you would find yourself in extremely familiar territory on side spin shots using your normal bridge length at which you regularly play and find a lot of consistency and a lot to hang onto. The way you regularly play is where I regularly play and make allowances as I don't use BHE and the perfect pivot point on all shots.

I chose the shafts I did based on the position of the pivot point because its very close to where I normally bridge so it takes very little effort for me to use BHE when it comes time to.

Most people aren't going to devote as much time as I have or Dr. Dave has into working on this end of the game they simply try to arrive at the best decision they can muster in order to make a shaft purchase.

Sadly Jacoby has quit making the shafts I bought for a newer version that they tout as playing stiffer. I'd like to test those new shafts but I have no intention of buying two new shafts when mine are perfectly fine and play great. I have seen some new to me shafts on the market called Keel wood I think. A friend of mine made him two shafts from it. It was brown and had dried under kiln conditions I believe so it was much drier and lighter than regular shaft wood. It was stiff playing and yet had great feel. I've not hit a ball with a carbon shaft. I can't imagine much less squirt than what I already experience but I'm open to it. I would be more impressed with a heightened feel added to the LD capabilities.

There is a lot to talk about when it comes to squirt and swerve but on the playing end things can be made a lot simpler and should be. Distance to the Object Ball, contact point, allowance for squirt or use BHE and much smaller allowance. I do like smaller allowances offered by LD shafts but I miss the feel of normal maple at times and keel wood is very interesting. Carbon I won't pay for because I don't feel I need that.

 

[dr_dave]

An LD shaft produces less CB deflection than a non-LD shaft.

With less CB deflection, the amount you need to adjust your aim is less.

For more info, see advantages of LD shafts.

Again, this is where I get confused. I totally understand the principles behind LD shafts. However I was under the impression that SAWS was kinda the counter argument to LD shafts. Where someone could aim exactly the same using sidespin, no matter what shaft they used.

The System for Aiming With Sidespin (SAWS) is based on a simple calibration procedure that teaches you the right combinations of BHE and FHE to use for shots of different distances and speeds. It works for any bridge length and any cue; but if you change either, you need to redo the calibration (or make adjustments, as covered on SAWS). There are still advantages to using an LD shaft because with less aim adjustment, there is less chance for making errors.

FYI, video demonstrations and much more info is available here:

aim compensation when using sidespin

Enjoy,
Dave

 

[jtompilot]

Pretty much. If you use parallel english using an LD shaft should result in less cb squirt. Of shafts i've used/owned/tried the 12.9 REVO had least amount of squirt. The Z was close but i just have never liked that taper style.

That’s strange. I’ve played with my Predator cue with the Z shaft a few times recently. It squirts way more than my custom diamond wood butt with the 314-3 or 12.4 Revo.
I was talking to Tony Chohan when he was in New Orleans for the 1P tournament about the 12.4 and 12.9 Revo. Marty in Detroit wanted to trade me his 12.9 for my 12.4 Tony said all the guys he knows likes the 12.4 better than the 12.9. I did hit several balls with the 12.9 but I’ll keep my 12.4 Thanks

Everyone likes something different

 

[BRussell]

There are still advantages to using an LD shaft because with less aim adjustment, there is less chance for making errors.

I think that he has a good point. If you can tell people for a wider range of shots to just aim straight and then pivot at your bridge, that seems more clear than getting into 50/50 BHE/FHE, which comes into play more with LD shafts. Do you agree? It seems to me that, with your system, you’re always adjusting for english, it’s just a matter of whether it’s more or less BHE or FHE adjustment. There’s nothing easier about adjusting for a lower-deflection shaft, you’re just getting a little higher FHE percentages.

One counter-example though: I’ve become a believer in LD break cues, because I believe unwanted english is very common on breaks, where people are swinging harder and more wildly. If you use a LD break cue with a pivot point close to the (usually long) bridge length of the break, the deflection will be automatically cancelled by the pivot. A normal shaft will have a pivot point much shorter than people’s typical breaking bridge length, and they won’t compensate enoguh for the unwanted deflection.

 

[dr_dave]

I think that he has a good point. If you can tell people for a wider range of shots to just aim straight and then pivot at your bridge, that seems more clear than getting into 50/50 BHE/FHE, which comes into play more with LD shafts. Do you agree?

Obviously, if there were one bridge length that worked with BHE alone for a wide range of shots, that would be the best approach, and this is one of the alternative methods covered on SAWS; however, as I demonstrate on SAWS, this doesn't work very well over a wide range of shots.

With a lower-CB-deflection shaft, or with a shorter bridge length, the percentage of FHE vs. BHE does increase; so for people who prefer to use BHE alone, a higher-CB-deflection shaft and/or a longer bridge length could give better results over a chosen range of shot speeds and distances.

It seems to me that, with your system, you’re always adjusting for english, it’s just a matter of whether it’s more or less BHE or FHE adjustment. There’s nothing easier about adjusting for a lower-deflection shaft, you’re just getting a little higher FHE percentages.

That's correct. Although, with less adjustment (e.g., a small FHE pivot vs. a large BHE pivot), there will be less chance for error (especially if a person's BHE pivot is sloppy, with bridge shift or distortion, which might be more of a problem with some closed-bridges).

Regards,
Dave