Bob Jewett...tip diam. discussion

ericyow

ericyow

WPA Masse World Champion
Silver Member
Bob, and twimc, I was at dinner at the close of the VF event with Paul Frankel (PQB), Tom Rossman (and Marty), and Mark Dimick, discussing tip diameter and the amount of spin associated with such. Our hypothetical was as follows: all things equal - same weight cue, same stroke, same power, same tip, etc - with the exception of tip diameter, which gets "more spin", a smaller diameter tip or larger diameter tip?

Tom proposed that carom players use smaller tips because of their increased spin. Paul says the smaller tips are utilized so the player can see where, on the ball, the tip is to hit with more precision. I continue to assert that a larger tip gets more spin, all things considered, because of a larger contact patch - where the tip hits the ball.

Fleshing out my theory, I proposed that if the shooter were to use the center point of the cue ball as a basis and shoot so that the left edge of the tip is, say, 1/4" out from center, to me, a larger diameter tip will get more spin due to the fact that more tip is contacting the ball. For the sake of argument we hypothesized two scenarios, a 12mm tip and a 14mm tip. While the difference wouldn't be much, I can't help but think the 14mm tip would get more for that reason.

On the other hand, one might presume that a smaller tip could hit "further out" from center by virtue of its size and precision. But, I must disagree, for the edge of the 12mm tip that hits "way out" wouldn't be any smaller or larger than the edge of the 14mm tip that extends just as far.

Bob, forgive me for not being able to articulate more of our discussion, but I will say this. At the table, we never agreed on a final answer. But, we all agreed that if anyone had the answer (or knew how to find it), you would.

Want to chime in?

-yow!
 
psykoyow said:
... Our hypothetical was as follows: all things equal - same weight cue, same stroke, same power, same tip, etc - with the exception of tip diameter, which gets "more spin", a smaller diameter tip or larger diameter tip?...
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There is a great deal of handwaving on this subject, but little measurement. If someone wants to claim a smaller tip does X, then they have to give you numbers: "with an 11mm tip, I can shoot straight into a cushion and bring the cue ball over 37 degrees, and with a 13 mm tip you cannot bring the ball over more than 28 degrees.." But no one is ever that specific that I've heard. The same goes, more or less, for hard/soft tips and acceleration/coasting stroke and tight/loose grip and aim-and-swoop (some say "tuck and roll") versus stroking straight through the shot. Lots of opinions and no data.

My opinion: the farther your tip is from the center of the ball, the more spin you will get on the ball up until you miscue. (Spin should be given as the ratio of spin to speed, or what is called the "quality" of the spin.) The eccentricity of the hit is far more important than any other factor in determining the quality of the spin, assuming the stick or tip is not flat-out defective.

Of course several things may keep you from getting very far out on the ball including bad chalk or a tip that doesn't take chalk. The squirt of the stick has some influence, and it seems that a squirtier stick will get lower quality spin. I think this effect is pretty small also.

So, I think the selection of tip diameter should be guided by considerations other than the maximum amount of spin that you might get on the cue ball.
 
I have often wondered why people would think that the actual tip diameter can effect the amount or type of spin imparted to the cue ball. I have to conclude that it must be some other factor (probably) directly related to the tip diameter: such as squirt, endmass, or tip radius.

It would seem to me that an 11mm tip with a dime radius and a 13mm tip with a dime radius would look identical to a cue ball, all other factors being equal.

Of course there are the psychological issues as well, however those would obciously differ from person to person.

jon
 
No science, just logic...

It would seem logical to me that the more area gripping the surface the more traction (translating into spin) you will get. There is a reason that dragsters use "slicks".
 
Perhaps we could compare the cue ball resting on a point of the tables surface to a wheel anchored to a vertical axle, now you hit either off center with an object to impart spin; the question is does the surface area of the object doing the hitting matter significantly? I don't think so. I think the straightness or quality of hit makes a much larger difference. Also, since the cue ball isn't anchored to a vertical axis, deflection or amount of squirt would be a more important calculation than the size of cue tip. I'm interested to hear from more of you on this.
 
And that was my theory as well. The larger the contact patch, the more friction.

One thing I've relied upon is my ability to masse better with a larger tip diameter. Other factors vary as well, but I can't help but think I'm getting more spin because of the nature of the hit.

I guess this question will get lost by the wayside, like many others, until someone takes it upon themselves to prove one way or the other.

Bob, thanks for your prompt reply.

-yow!
 
Catahula said:
It would seem logical to me that the more area gripping the surface the more traction (translating into spin) you will get. There is a reason that dragsters use "slicks".
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Tip-to-ball is static friction (no slipping) and relatively simple. The stuff going on between a dragster tire and the pavement is much, much more complicated.

If you do want more gripping area, I think it will be far more effective to use a softer tip rather than a larger one, but I don't think the effect is important.
 
I feel it has to do more with the shaft than the tip size, I use to play with a Meucci (before Red dot shafts) with a Elk Master and I must say, this was the most engish happy cue ever. The newer Meucci's are a far cry from what they used to be thats for certain.


I hate to keep kicking a dead horse, Meucci had something speacial once upon a time, My Mentor owned a Balabushka, (the real deal) and that was the only cue Ive hit with that surpassed My giant killer Meucci's ability to spin the ball.

Even some of the Older Meucci's didnt compare, Id like to have that cue, measure every lil detail and have a cue made to those specs, after many years and 100's of cues I havent found anything that I truely like as much as my old Meucci.

Whether its tip size or something to do with the shaft, Im uncertain, Im only positive that I wont take my game serious untill I find a cue to whitch my stlye was created.




SPINDOKTOR
 
I was trying to articulate my belief that as long as you have the same radius of curvature of the tip, it shouldn't matter what the diameter is! We're basically talking about the collision of a round ball and a rounded leather tip. I have attached an image which I think explains what I'm trying to say here.

If you want to maximize the contact patch, I think you'd want to go with larger tip curvature (nickel instead of dime) and a softer tip. Keep in mind though that with a nickel tip curvature you'll be getting less contact patch offset from center ball for the same cue offset. Because it has less curvature, the contact point of the tip and ball will be closer to center ball for the same cue stick offset. So it would seem that a nickel curvature is getting less spin, but that would only be because there is less offset to the contact point.

Personally I can't see how the contact patch size should effect the amount of spin! If there is no slippage between the tip and the CB with a small contact patch, then a larger contact patch cannot create more spin. It would be easy to tell if there is slippage - that's called a miscue. I will say for sure that my assumption of "no slippage on non-miscue hit" needs more study!

jon
 

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Size DOES matter...

Holy crap did that one diagram just change my entire view of things!

At first I was under the same impression as jondrums - The tip would look the same to the cueball. What this diagram did is show another area that I think makes it more clear.

Basically if the cue is accelerating through the ball, the larger tip would stay in contact with the cb more than a smaller tip could. That extra contact would allow the tip to impart more spin than a smaller tip.

I think that would also explain the phenomenon that pyskoyow described that he can masse better with a larger tip. The table is forcing contact with the cueball for as long as possible, and a larger tip means longer contact, and thereby increased spin.

I think that also explains the drag racing analogy, too. If you put thinner tires on a dragster, it will not run as fast. Even if they tuned it down so that the horsepower doesn't break the traction of the thinner tires (which they still do even with bigger tires) the fact remains that if traction is limiting transfer of energy, increasing the surface area will increase traction and will therefore increast potential energy transfer.

All this from that ONE diagram, too!!!
 
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Dakota Cues said:
H... Basically if the cue is accelerating through the ball, the larger tip would stay in contact with the cb more than a smaller tip could. That extra contact would allow the tip to impart more spin than a smaller tip. ...
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While that may seem like a reasonable statement on the surface, if you look more closely, it's exactly backwards. There is an excellent argument that in fact you want to reduce contact time for more spin. If the tip is on the ball for an extended period of time, it will ride further around the side of the ball and go out into miscue territory.

There are many things about billiard physics that go against "common sense."
 
jondrums said:
I was trying to articulate my belief that as long as you have the same radius of curvature of the tip, it shouldn't matter what the diameter is! We're basically talking about the collision of a round ball and a rounded leather tip. I have attached an image which I think explains what I'm trying to say here.

If you want to maximize the contact patch, I think you'd want to go with larger tip curvature (nickel instead of dime) and a softer tip. Keep in mind though that with a nickel tip curvature you'll be getting less contact patch offset from center ball for the same cue offset. Because it has less curvature, the contact point of the tip and ball will be closer to center ball for the same cue stick offset. So it would seem that a nickel curvature is getting less spin, but that would only be because there is less offset to the contact point.

Personally I can't see how the contact patch size should effect the amount of spin! If there is no slippage between the tip and the CB with a small contact patch, then a larger contact patch cannot create more spin. It would be easy to tell if there is slippage - that's called a miscue. I will say for sure that my assumption of "no slippage on non-miscue hit" needs more study!

jon
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Very good scenario & a true explanation, I might add (JMHO). I have always liked the nickle radius, 13mm & a Triangle medium hardness Tip. I can draw the ball very well & control the cue ball's path (after impact). Other players that I play with, & compete against, have some of the same type equipment & some have different equipment. It's the chocolate & vanilla syndrome.
 
The way this was explained to me, and which I agree w/given my M.E. background, is that the amount of spin is proportional to the pressure at the point of contact. Pressure is Force per Area, so the same force applied over a smaller area generates higher pressure than the same force over a larger area.
 
Endymion said:
The way this was explained to me, and which I agree w/given my M.E. background, is that the amount of spin is proportional to the pressure at the point of contact. Pressure is Force per Area, so the same force applied over a smaller area generates higher pressure than the same force over a larger area.
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No, the amount of spin relative the speed of the cue ball -- that's the important thing -- is proportional to the lever arm -- how far from the center you hit the ball. The relevant topic in ME is the "impulsive force" approximation. The speed of the cue ball and the amount of spin is proportional to the integral of force parallel to the stick versus time. If you do the integral, you will see that you can have a higher force for a shorter time or a lower force for a longer time and get to the same speed/spin. Further, you can have the same force with a large pressure over a small area or a small pressure over a large area.
 
jondrums said:
I was trying to articulate my belief that as long as you have the same radius of curvature of the tip, it shouldn't matter what the diameter is! We're basically talking about the collision of a round ball and a rounded leather tip. I have attached an image which I think explains what I'm trying to say here.

If you want to maximize the contact patch, I think you'd want to go with larger tip curvature (nickel instead of dime) and a softer tip. Keep in mind though that with a nickel tip curvature you'll be getting less contact patch offset from center ball for the same cue offset. Because it has less curvature, the contact point of the tip and ball will be closer to center ball for the same cue stick offset. So it would seem that a nickel curvature is getting less spin, but that would only be because there is less offset to the contact point.

Personally I can't see how the contact patch size should effect the amount of spin! If there is no slippage between the tip and the CB with a small contact patch, then a larger contact patch cannot create more spin. It would be easy to tell if there is slippage - that's called a miscue. I will say for sure that my assumption of "no slippage on non-miscue hit" needs more study!

jon
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check this out...

http://www.youtube.com/watch?v=i-MGmQG62qc
 
This is a very interesting thread.

I have no scientific data to contribute or numbers to post, however, I will say this.....I personally prefer a larger tip for the games of eight-ball and nine-ball, snooker simply demands a smaller tip due to the size of the balls. My personal regular shooting cue is an old A. E. Schmidt with a 14mm shaft and a good ol' fashioned LePro tip. During my 35 years of pool playing, I have never had a cue that has given me such good control and touch as this old piece of wood does, and I firmly believe it is due to the diameter of the tip and the stiffness of the shaft(as a result of the taper).
 
?????????

Smaller tip imparts more english! Try masse with 14mm an with 12mm. I rest my case! The reason is there is a 12mm shaft behind a 12mm tip.
Pinocchio
 
Mr Yow had actually posted earlier that he prefers a thicker tip for masse shots.

I think this post needs to get beyond anecdotal evidence, and try and understand the physics of what's happening. Jewett seems to be the most competent at addressing the issue, and yet it's clear that intuition here seems complexing when faced with the facts. There's no clear simple logic that can easily explain either case. And the anecdotal evidence seems to differ from person to person. I know what I think just in terms of the tip sizes I've used, but I think really it would waste forum space. I'd rathe here or see real evidence and theories.

Would considerations of tip mass or stiffness have much to do with it, from an ME standpoint? How would it affect the spin/speed ratio?

And are we wrong to asume that the amount of max spin between two different shaft diameters is the same?



Pinocchio said:
Smaller tip imparts more english! Try masse with 14mm an with 12mm. I rest my case! The reason is there is a 12mm shaft behind a 12mm tip.
Pinocchio
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Tip Diam. Discussion

3 Cushion players use balls bigger than pool players and yet they use a smaller tip diameter when compared to pool. They also use a stiffer shaft.

Point to consider: With everything equal except the diam. of the shaft one must consider the transfer of energy from the pool cue to the cue ball. This energy transfer would be the same for both cues except the smaller shaft would transfer more energy to a smaller area of the cue ball therebye creating a larger impact (in that area) and therebye creating more spin.

Looking at extremes, using a 5 mm shaft for breaking would probably cause the shaft to break simply because of all the energy transfer would go thru such a small area at the end of the cue.

And thats my 2 cent opinion!
 
I've officially opened the can of worms, I'm sure. But, in my (short) years in the game, I have't come across anything certain on the issue.

For kicks, on the billiard table, I shot from the head spot into the 2 diamond on the long rail (so I shot along the headstring) with max left. I marked the place it hit on the opposite rail and kept doing it over and over with my 13mm sniper McDermott until I was satisfied that I found the place where I got the most spin. Of course I varied my speed, stroke, and other variables. Then, I did it all over again with my 12mm sniper Joss with Z2 shaft. Again, using max left, I was able to duplicate the same amont of spin, maybe even just a little more, but without certainty that I was hitting the exact same spot on the first rail, I can't be sure either way.

In sum, my test was inconclusive. My test would yeild better results if I had a 14 mm vs 8 mm or something. But again, all other variables must be equal to be conclusive.

I'll let Tom know what we've (failed to) come up with on the matter. For now, I've got other things to think about. Thursday I'll be in NYC practicing with Miguel Torres and Mike Massey for the ESPN gig. I'll ask Miguel what he thinks about our tip diameter question. I'll get back to ya'll on the matter later.

-yow!
 
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