Advice on shafts with low throw?

Zieglermt said:
Well, since you asked, I have a very straight stroke and it's not like I'll be doing this with the obj ball very far away. That's why I'll take an avg of 5 hits at each cut. Heck, I'll probably do a lot more than 5, just figured 5 was a good base. Also, instead of aiming for a spot on the ball or a pocket I will be aiming for the mark on the table in front of the obj ball, which will be dead center under the ghost ball. I will be doing these shots at a pretty low speed so it maximizes the throw affect and so that my friend can mark where the obj ball meets the rail or pocket each time. I also have a measles cue ball so it will be easy to aim for the same proportioned measure of english for each cue. Not exactly a vacuum test setting but I will be careful.

And I realize this may have nothing to do with why you asked, but spin induced throw is easy to measure if we are examining a straight on contact, as Dave has already demonstrated. But if you really want to see spin throw variation you need to do it with a cut shot, not a dead straight-on shot where the throw will be limited. Straight on contact mitigates the effect of spin induced throw, because there is more static friction generated on a cut shot than with a straight on shot... Not to sound pretentious or anything. You mightve already been aware of this. And this is just pure speculation on my part, but if you hit an object ball full there is a much much higher energy transfer between balls which I think would mean less contact time. That notion combined with a lack of the aforementioned static friction effect might better explain straight-on throw mitigation to those who were previously unaware.

So yes, it will be more difficult to accurately measure throw on a cut shot, but the results will be way more conspicuous.
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Sorry, but this is pretty much all wrong - assumptions, conclusions and testing methods. Your test can't reveal anything.

pj
chgo
 
KMRUNOUT said:
I do not know if anyone has broken down the physics on what effect if any this lateral force can have at the brief moment of contact. It would be an interesting study though.
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The lateral (transverse or sideways) motion of the end of the shaft during tip contact (along with the mass involved in this lateral motion) is what causes squirt (cue ball deflection), and differences in squirt can have differences in the amount of spin (for a given tip contact point). I have studied this, and the anaylsis and results can be found here:

getting more spin with an LD shaft

Enjoy,
Dave
 
Zieglermt said:
Well, since you asked, I have a very straight stroke and it's not like I'll be doing this with the obj ball very far away. That's why I'll take an avg of 5 hits at each cut. Heck, I'll probably do a lot more than 5, just figured 5 was a good base. Also, instead of aiming for a spot on the ball or a pocket I will be aiming for the mark on the table in front of the obj ball, which will be dead center under the ghost ball. I will be doing these shots at a pretty low speed so it maximizes the throw affect and so that my friend can mark where the obj ball meets the rail or pocket each time. I also have a measles cue ball so it will be easy to aim for the same proportioned measure of english for each cue. Not exactly a vacuum test setting but I will be careful.

And I realize this may have nothing to do with why you asked, but spin induced throw is easy to measure if we are examining a straight on contact, as Dave has already demonstrated. But if you really want to see spin throw variation you need to do it with a cut shot, not a dead straight-on shot where the throw will be limited. Straight on contact mitigates the effect of spin induced throw, because there is more static friction generated on a cut shot than with a straight on shot... Not to sound pretentious or anything. You mightve already been aware of this. And this is just pure speculation on my part, but if you hit an object ball full there is a much much higher energy transfer between balls which I think would mean less contact time. That notion combined with a lack of the aforementioned static friction effect might better explain straight-on throw mitigation to those who were previously unaware.

So yes, it will be more difficult to accurately measure throw on a cut shot, but the results will be way more conspicuous.
Click to expand...
As PJ pointed out, there are many innacuracies in this post. Throw varies with cut angle, speed and spin in very complicated ways. If you haven't watched the following video yet, check it out (and if you have watched it before, maybe watch it again). It summarizes and demonstrated many of the important effects:

NV B.86 - Cut-induced throw (CIT) and spin-induced throw (SIT), from VEPS IV

Also, items 16-37 in the numbered list beneath the videos and illustrations on the squirt, swerve and throw effects resource page cover all throw effects in great detail (along with supporting resources).

I agree with others that the type of cue or tip has no direct effect on throw. However, because of the complexities of squirt, swerve, and throw, if one is not careful when performing comparative tests, anything can seem possible. For example, if you compare different shafts and/or tips, the amount of throw can seem different if the aim isn't compensated properly to adjust for the different amounts of squirt. And if different shot speeds are used (e.g., maybe because the different tips result in different CB speeds, even with the same stroke), then the amounts of both swerve and throw can be different.

Again, as PJ pointed out, experiments involving throw measurements must be done with caution, controlling all important variables extremely carefully. Otherwise, the results can be misleading.

Regards,
Dave
 
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Patrick Johnson said:
Sorry, but this is pretty much all wrong - assumptions, conclusions and testing methods. Your test can't reveal anything.

pj
chgo
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Yeah it's easy to refute speculation. When I was talking about full obj ball contact I was saying this was a theory of mine. I wasn't trying to pass it off as fact. If you can disprove my last post about kinetic friction that would actually be impressive. If you disprove hundreds of years of scientific theory on friction you would be the high authority on billiard physics and I will give you a gold star next to your name on the board and maybe a cookie.

Also, I never promised accurate results. The only thing I promised to do was test it out because I was curious. I never promised perfection. The would be idiotic on my part if I actually thought I would produce near perfect results. Maybe my test won't reveal anything but I know judging spin with a house cue is way easier for me than trying to judge it with a z2. And that is really all this thread was about. But you had to try and commandeer this thread like an annoying pedant. Unless you have any substantiating proof to correct my kinetic friction post or you have any good shaft ideas why dont you go back to youtube and argue with the 12 year old trolls, maybe you'd be more welcome there.
 
Zieglermt said:
...why dont you go back to youtube and argue with the 12 year old trolls
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No need for that - they find us here easily enough.

Sorry I was curt, but sometimes it's best to cut to the chase so things are clear.

There's lots of technical info on Dr. Dave's website - a guy with curiosity like yours about how things work should find it interesting.

http://billiards.colostate.edu/

pj
chgo
 
Zieglermt said:
Well, since you asked, I have a very straight stroke and it's not like I'll be doing this with the obj ball very far away. That's why I'll take an avg of 5 hits at each cut. Heck, I'll probably do a lot more than 5, just figured 5 was a good base. Also, instead of aiming for a spot on the ball or a pocket I will be aiming for the mark on the table in front of the obj ball, which will be dead center under the ghost ball. I will be doing these shots at a pretty low speed so it maximizes the throw affect and so that my friend can mark where the obj ball meets the rail or pocket each time. I also have a measles cue ball so it will be easy to aim for the same proportioned measure of english for each cue. Not exactly a vacuum test setting but I will be careful.

And I realize this may have nothing to do with why you asked, but spin induced throw is easy to measure if we are examining a straight on contact, as Dave has already demonstrated. But if you really want to see spin throw variation you need to do it with a cut shot, not a dead straight-on shot where the throw will be limited. Straight on contact mitigates the effect of spin induced throw, because there is more static friction generated on a cut shot than with a straight on shot... Not to sound pretentious or anything. You mightve already been aware of this. And this is just pure speculation on my part, but if you hit an object ball full there is a much much higher energy transfer between balls which I think would mean less contact time. That notion combined with a lack of the aforementioned static friction effect might better explain straight-on throw mitigation to those who were previously unaware.

So yes, it will be more difficult to accurately measure throw on a cut shot, but the results will be way more conspicuous.
Click to expand...

The only thing patrick johnson is unaware of when it comes to pool is how to cue a ball.
 
Patrick Johnson said:
I don't doubt your word, but I'm skeptical of your testing methods - because I've done scores of shots with dozens of shafts/tips and have never found a significant difference between any of them - if I control the test variables.

For the test to be meaningful you have to be able to objectively verify that "all things are equal" for every shot - and that takes a little planning and care, but can be done without special equipment. Here's the test I suggest (it's been posted a few times before):



pj
chgo
Click to expand...

Well I can tell you I'm not a robot, but we both setup the same shot with the same low right spin and got to the same spot with the same shaft. Then changed shafts, and got to a different spot. Yes there was a bit of variance since it's impossible for a human to hit the exact same spot with the exact same speed. All I know is that if I hit a shot 5 times and it goes within 1/2 ball of one spot, then shoot it again and it goes within 1/2 ball of a different spot each time, and a third time with a third shaft and we hit a different point, that shows me the difference is in the shaft. It was not one person testing, but two and we both were sending the cueball in the same area with the same shaft. He has a bit better hit on the ball so was getting down lower on the rail than me, but still it went regular shaft, regular shaft with layer tip, LD shaft with regular tip, LD shaft with layered tip in how much spin we got no matter who was shooting.

I am thinking if someone contacted the research groups that made the pool playing robots and got them some shafts, they can run the same spin tests but with an exact hit and force each time.
 
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hang-the-9 said:
...it's impossible for a human to hit the exact same spot with the exact same speed.
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It's easy for a human to hit the same spot and speed; it's just hard to do it every time. You need a way to know when you do it successfully so you can count those shots and ignore the rest. That's what the test posted above does.

We're fully capable of (even talented at) fooling ourselves.

pj
chgo
 
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