Does Tip Hardness Influence Cueball Deflection?

S

shankster8

AzB Silver Member
Silver Member
I sent the following PM to dr_dave yesterday, but now believe I should have posted it on the main forum for the benefit of all. Though this was originally addressed to dr_dave, I encourage anyone with input on this matter to reply. Thanks

"Hello dr_dave. Thanks alot for sharing all your insights and research findings. I've learned alot from your input to this forum.

I've reviewed your literature regarding deflection, and cannot find an answer to the question "Does tip hardness influence cueball deflection?" Thus, I assume you have found no corolation between the two. But I still have this question nagging at me, cause something keeps telling me there may be a relationship - like, a softer tip will remain in contact with the cb longer, thus expanding the length of time the forces underlying deflection have to operate. I sure wish you would answer this question for me, so I can forget about it (and so I can experiment with softer tips). Thanks, Hank"
 
I've found I play MUCH better with a harder tip. Soft tips play inconsistent to me. May be due to what you are saying.
 
Stiff or whippy shafts make a difference so by logic a tip must to to some degree Im guessing.
 
randyg said:
Cueball squirt?????
Click to expand...

Randyg, is that an answer, or a question, or what? Did I use a word wrong? Does "deflection" only refer to a shaft, and not a cueball? Did you not understand what I was asking? Help us out here, it just takes a few more keystrokes.
 
Nostroke,

The stiffness of a cue shaft has no real bearing on cue ball deflection, or squirt. If the cue shaft is so thick that it is heavier in the "effective tip end mass", then the extra weight will change it, but not the stiffness.

I don't think the hardness will have any appreciable effect, but I am interested to see what Dr. Dave has to say. Also, Bob Jewett, what do you think?


Royce Bunnell
 
shankster8

Technically, squirt is what the cue ball does, and deflect is what the shaft does.

Often these are used interchangably, but technically, that is wrong.
 
shankster8 said:
Does Tip Hardness Influence Cueball Deflection?
Click to expand...
There have been a number of very technical threads with posts by (IMO) the brightest AZ Posters, including Dr. Dave, B.Jewett, and M.Page. On top of that, there have been discussions related to experiments, high speed video, and other articles/information related to this topic. IIRC, a very complete thesis related to this topic is also available somewhere. [This is a little fuzzy, but I do think I read it]

If you did a search, I'm sure you could take up an entire weekend reading the information. The key point being, do a search...

The short answer is: it depends, but generally, not much if at all.

-td
 
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RBC said:
Nostroke,

The stiffness of a cue shaft has no real bearing on cue ball deflection, or squirt. If the cue shaft is so thick that it is heavier in the "effective tip end mass", then the extra weight will change it, but not the stiffness.

I don't think the hardness will have any appreciable effect, but I am interested to see what Dr. Dave has to say. Also, Bob Jewett, what do you think?


Royce Bunnell
Click to expand...


Ok you probably know more than me. I had thought if the shaft gave (whippy) that the CB would squirt/deflect less as the shaft was giving instead of the ball so to speak. Maybe this was 'old schol thought'. Sorry for the bad info.
 
I'll share my PM response here also so others can benefit:

See my August '08 article. Tip hardness has only a slight effect on squirt (AKA "cue ball deflection"). In the article, I show plots of real data taken with a cue-testing robot.

Regards,
Dave

shankster8 said:
I sent the following PM to dr_dave yesterday, but now believe I should have posted it on the main forum for the benefit of all. Though this was originally addressed to dr_dave, I encourage anyone with input on this matter to reply. Thanks

"Hello dr_dave. Thanks alot for sharing all your insights and research findings. I've learned alot from your input to this forum.

I've reviewed your literature regarding deflection, and cannot find an answer to the question "Does tip hardness influence cueball deflection?" Thus, I assume you have found no corolation between the two. But I still have this question nagging at me, cause something keeps telling me there may be a relationship - like, a softer tip will remain in contact with the cb longer, thus expanding the length of time the forces underlying deflection have to operate. I sure wish you would answer this question for me, so I can forget about it (and so I can experiment with softer tips). Thanks, Hank"
Click to expand...
 
dr_dave said:
I'll share my PM response here also so others can benefit:

See my August '08 article. Tip hardness has only a slight effect on squirt (AKA "cue ball deflection"). In the article, I show plots of real data taken with a cue-testing robot.

Regards,
Dave
Click to expand...

Dr_dave, I read your article and, as usual, great information presented there. Thanks for the hand!!
 
RBC said:
Nostroke,

The stiffness of a cue shaft has no real bearing on cue ball deflection, or squirt. If the cue shaft is so thick that it is heavier in the "effective tip end mass", then the extra weight will change it, but not the stiffness.
Click to expand...
I'll have to register a little bit of a dissenting vote. Stiffness does have something to do with squirt since it affects the shape of the shaft as it bends. The shape determines the amount of mass that gets set into motion in the sideways direction. For example, try applying a load to a thin rod made out of wood versus one made out of steel, or a thick one made out of wood. Since we're dealing with shafts made of similar materials at roughly the same thickness, the mass is the major factor, though.

Jim
 
Yes, Generaly speaking

Tip hardness is generally associated with tip density. Added density is added deflection. I adjust aim through the aging of my tips on my playing shafts, and compensation is MINIMAL. However, I play with a traditional shaft, not a predator. In theory, The Node point(Hold your cue and smack it sideways with your palm. where it vibratesleast are the nodes - up to three on a cue) is the answer. The weight and density of the contact point at the cueball, in my understanding, is compared to the densty at the node point, and is affected by the length between contact and node point.
shankster8 said:
I sent the following PM to dr_dave yesterday, but now believe I should have posted it on the main forum for the benefit of all. Though this was originally addressed to dr_dave, I encourage anyone with input on this matter to reply. Thanks

"Hello dr_dave. Thanks alot for sharing all your insights and research findings. I've learned alot from your input to this forum.

I've reviewed your literature regarding deflection, and cannot find an answer to the question "Does tip hardness influence cueball deflection?" Thus, I assume you have found no corolation between the two. But I still have this question nagging at me, cause something keeps telling me there may be a relationship - like, a softer tip will remain in contact with the cb longer, thus expanding the length of time the forces underlying deflection have to operate. I sure wish you would answer this question for me, so I can forget about it (and so I can experiment with softer tips). Thanks, Hank"
Click to expand...
 
kamui tip different

with all kamuii's I think hardness doesn't influence because its lack of proporsity.(tip doesn't compress and spring back) If the leather tip flexes theres's cueball deflection. How about the ferrule material and the shaftwood. It only gets worse. mark
 
jal,

While you are right in that the stiffness does have some effect, it is very very minimal. As I stated, squirt is determined by "Effective" tip end mass. Stiffness may, and this is controversial, contribute to Effective tip end mass, but it is so slight that the difference would likely not be measurable. Read Dr Dave's articles and tests on the "Beaver" shaft. You will find it here. He basically tested this very thing.

http://billiards.colostate.edu/bd_articles/2008/aug08.pdf

Eyesjr,

You absolutely right. The mass of the tip, which is affected by it's density and size, will definately change the squirt of a cue shaft. However, it is certainly possible to have a hard tip and a soft tip with the same mass, which would mean that there density would have no effect.


I would like to thank Dr Dave, Bob Jewett, and Mike Page for all they have done to provide us with answers to questions like these.


Royce Bunnell
www.obcues.com
 
Question for the robot

dr_dave said:
See my August '08 article. Tip hardness has only a slight effect on squirt (AKA "cue ball deflection"). In the article, I show plots of real data taken with a cue-testing robot.

Regards,
Dave
Click to expand...

But does your robot hit nearer the center of the cb when using a harder tip? I know I do - or at least I think I do (but unless the wife has a last minute change of heart and gives me a high speed camera for Christmas instead of socks, it will remain supposition :smile: ).
 
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only good boys get HSV cameras for Christmas

Siz said:
But does your robot hit nearer the center of the cb when using a harder tip?
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I'm not sure what your mean here. The robot delivered the cue at the same offset every time (regardless of the tip hardness). Or are you thinking about how the tip might interact with the CB differently based on the hardness. FYI, clips HSV A.98 through A.109 show various shots for different hardness tips, but the clips might not show what you want to see.

Siz said:
I know I do - or at least I think I do (but unless the wife has a last minute change of heart and gives me a high speed camera for Christmas instead of socks, it will remain supposition :smile: ).
Click to expand...
Good luck with your Christmas gift wishes. Have you been a good by this year? :wink:

Regards,
Dave
 
This is my guess:

Tip hardness WILL affect cue ball squirt.

Tip-ball friction (which is affected by tip hardness, chalk condition, humidity, cue ball condition and possibly other factors) will affect cue ball squirt. Here's why I think so:

If there was NO friction between the tip and ball, the ball would bounce off the tip, like an OB bounces off of a CB, in the direction of the contact line, the equivalent of "100% squirt."

But, due to tip-ball friction, the cue ball follows the cue axis to some degree, resulting in something less than 100% squirt. Because of tip-ball friction, there is the equivalent of the "throw effect" between the tip and the cue ball.

Tip hardness affects tip-ball friction, which affects squirt.

Is it possible to get the same friction with a hard, well-chalked tip as with a soft, poorly chalked tip? Yes, of course, but all things being equal, hardness affects friction.

I suspect the effect is small.
 
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