Does anyone know the coefficient of friction between cue ball and tip?

[Pubo]

So I'm still thinking about the miscue limit mentioned by Dr.Dave, and I'm wondering if anyone knows the COF (static and sliding) between the cue ball and a leather tip (chalked and no-chalk)? If not, I'll do an experiement myself and report up here.

 

[garczar]

So I'm still thinking about the miscue limit mentioned by Dr.Dave, and I'm wondering if anyone knows the COF (static and sliding) between the cue ball and a leather tip (chalked and no-chalk)? If not, I'll do an experiement myself and report up here.

Seriously???? No offense but does anyone really care?? By knowing will you play one bit better? Really sounds like a justnum project to be honest.

 

[Pubo]

By knowing will you play one bit better?

No, and I don't intend to improve my skill by knowing it to begin with.

does anyone really care??

You don't care doesn't mean no one cares.

 

[kling&allen]

So I'm still thinking about the miscue limit mentioned by Dr.Dave, and I'm wondering if anyone knows the COF (static and sliding) between the cue ball and a leather tip (chalked and no-chalk)? If not, I'll do an experiement myself and report up here.

Dr Dave has some values here

Pool Physics Property Constants - Dr. Dave Pool Info

Answers to frequently-asked questions about physical properties related to billiard and pool physics.

billiards.colostate.edu

 

[justnum]

This feels repetitive to measuring cue hardness.

If you do the work can you use different chalk brands for promotional purposes.

 

[Pubo]

Dr Dave has some values here

Pool Physics Property Constants - Dr. Dave Pool Info

Answers to frequently-asked questions about physical properties related to billiard and pool physics.

billiards.colostate.edu

awesome!!!

 

[kling&allen]

awesome!!!

Look for open source billiard software on GitHub as well, they will have libraries of constants you can repurpose.

 

[Pubo]

Look for open source billiard software on GitHub as well, they will have libraries of constants you can repurpose.

Thanks. I'm not make a billiard game, just curious what is the case in real-world situation. Can confirm that the tip-ball COF listed on Dr.Dave's webpage is for a chalked tip and the ball, NOT bare tip.

 

[Bob Jewett]

Thanks. I'm not make a billiard game, just curious what is the case in real-world situation. Can confirm that the tip-ball COF listed on Dr.Dave's webpage is for a chalked tip and the ball, NOT bare tip.

For an object rubbing against an inclined surface, like a tip against a cue ball, the angle of the surface at which slip first occurs gives the coefficient of friction by the simple formula tan(angle) (unless I forget my high school physics, which was a while ago). In the case of a sphere, the listed coefficient of 0.6 is the correct distance from center where a miscue for a chalked tip typically occurs. The value for a bare tip is not very interesting.

 

[Pubo]

For an object rubbing against an inclined surface, like a tip against a cue ball, the angle of the surface at which slip first occurs gives the coefficient of friction by the simple formula tan(angle) (unless I forget my high school physics, which was a while ago). In the case of a sphere, the listed coefficient of 0.6 is the correct distance from center where a miscue for a chalked tip typically occurs. The value for a bare tip is not very interesting.

Yes. But Dr.Dave thinks it's not as simple as that, he said, https://forums.azbilliards.com/threads/premium-chalks-–-are-they-worth-it.558248/page-6

It is not really about sliding friction. It is much more complicated, having to do with how the tip and shaft respond to the impact of the angled surface or with how the abrasive particles in the chalk engage both the tip and the CB. It is not sliding friction that keeps the surfaces engaged during contact. It is the chalk particles digging into both the tip and CB, creating a mechanical connection. This connection can’t seem to support itself with hits beyond the miscue limit. Maybe the chalk particles kind of roll out of the surfaces or break at the miscue surface angle.

That's why I want to understand this more. Do you think the sliding friction explanation is the answer?

 

[straightline]

This may be related. I discovered that <my> draw shots are speed related and that there is a very steep, cue speed related break point at near the miscue limit of the draw zone. IOW too hard and I have a stun stop instead of effortless draw. There's a lot I don't get about this. Speed window of the chalk?

 

[DeadStick]

This may be related. I discovered that <my> draw shots are speed related and that there is a very steep, cue speed related break point at near the miscue limit of the draw zone. IOW too hard and I have a stun stop instead of effortless draw. There's a lot I don't get about this. Speed window of the chalk?

Then your “too hard” shots result in either a) unintentional tip contact near center ball, or b) partial miscues that don’t apply much backspin to the ball (rare I would think - I’ve never experienced this). There are no other explanations that physics will support.

 

[straightline]

Then your “too hard” shots result in either a) unintentional tip contact near center ball, or b) partial miscues that don’t apply much backspin to the ball (rare I would think - I’ve never experienced this). There are no other explanations that physics will support.

I checked this extensively - by doing it; no high speed anything, and watching cue ball last. The strokes are always below center with the upper half of the tip in the zone. The cloth isn't very slick but the abrupt change in action is what concerns me. Anyway the point being, the friction coefficient might be affected by the dynamics of the shot.

 

[Mark V]

Moori? Elkmaster? Triangle? Is it glazed over? Which chalk? How much chalk? How well did you chalk it? What’s the humidity in the room? Which brand ball? Polished or rubbed down with rubbing alcohol?

I love nerding out on stuff like this.

The question has tons of variables that may or may not change the value. Physics was 20 years ago for me.

 

[garczar]

You guys are waaaay too bored. Might want to get outside some. Played for 40+yrs, at times pretty well, and i can honestly say that the word 'coefficient', of ANYTHING, has never come up. My curiosity starts with aiming and ends with pocketing my shot/get shape. All this minutia really means nada. Whatever floats one's 'boredom barge'.

 

[rexus31]

Can we move this to the Physics Section? Oh wait, there isn't one...for good reason. 99 posts in and this is what Pubo brings to the community. God help us.

 

[jsp]

You guys are waaaay too bored. Might want to get outside some. Played for 40+yrs, at times pretty well, and i can honestly say that the word 'coefficient', of ANYTHING, has never come up. My curiosity starts with aiming and ends with pocketing my shot/get shape. All this minutia really means nada. Whatever floats one's 'boredom barge'.

Can we move this to the Physics Section? Oh wait, there isn't one...for good reason. 99 posts in and this is what Pubo brings to the community. God help us.

You guys are free to simply ignore the thread.

EDIT: Cool, we get to 'downvote' posts now.

 

[garczar]

Can we move this to the Physics Section? Oh wait, there isn't one...for good reason. 99 posts in and this is what Pubo brings to the community. God help us.

agree here. you've heard of 'dead money' in a tournament? well, i guess there's 'dead posting' on on-line forums. i was at a golf show once and heard two club designers talking about shaft flex and driver head COR. i lasted about 30sec before i felt my head exploding.

 

[garczar]

You guys are free to simply ignore the thread.

EDIT: Cool, we get to 'downvote' posts now.

One step better than that, Ignoring puba or pubo or whatever it is. If this thread is any indication of his future work he's going right in with justnum.

 

[Texas Carom Club]

analysis paralysis