Squirt. End Mass and Cue Flexibility.

When I bought a slightly used OB Classic shaft to try, it had a new Kamui Super Soft tip on it at full height.

Even though I've played with very soft Elk Master & Blue Diamond tips for more the 4 1/2 decades, it was too soft even for me.

It was like bubble gum sticking to the ball.

Someone here suggested that I take a few layers off at a time until I got it to where I like it.

I did just that & it was not too many. Three(3) taken off at 1st & then another two(2).

It's played fine ever since.

Now how can just five(5) very thin layers of leather make such a difference?

You guys are over thinking this

Bank it said:

You guys are over thinking this

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Back in the 60s at the Tournament here in New Orleans, Jack Nicklaus drove a dog leg par 4 by taking the ball up over the trees straight to the green. It was later measured to be a 345 yard shot.

That was with a persimmon wood head driver with a plastic insert & a steel shaft... & a soft Balata covered golf ball.

He was probably the only pro golfer that could do that at that time.

Now with today's equipment, there is no telling how many pro golfers can do that.

Knowledge & technology can make more players 'better' or I guess I should say play better.

But yes sometimes matters are over thought.

That reminds me of the time NASA was moving something by truck that would not fit under an overpass & they, the engineers, were all looking at how they could section off a part of the overpass & how they could jack it up...

Then a little boy just blurted out...

'why not just let some air out of the tires?'.

:wink:

Bank it said:

You guys are over thinking this

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That's what they told Coriolis.

Thank you kindly.

dr_dave said:

We also faced and addressed this problem with the machine we designed and built at Colorado State University. More info on this topic can be found here:

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Have you looked at this cue testing machine before?

http://dbkcues.ru/articles-2/cue-testing-unit/?lang=en

Sloppy Pockets said:

Have you looked at this cue testing machine before?

http://dbkcues.ru/articles-2/cue-testing-unit/?lang=en

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Yes I have. That's the kind of "non-human, rigid bridge" that can affect squirt (if the bridge length is less than 8 inches or so), as described on the squirt bridge-length effects resource page.

Regards,
Dave

ENGLISH! said:

When I bought a slightly used OB Classic shaft to try, it had a new Kamui Super Soft tip on it at full height.

Even though I've played with very soft Elk Master & Blue Diamond tips for more the 4 1/2 decades, it was too soft even for me.

It was like bubble gum sticking to the ball.

Someone here suggested that I take a few a layers of at a time until I got it to where I like it.

I did just that & it was not too many. Three(3) taken off at 1st & then another two(2).

It's played fine ever since.

Now how can just five(5) very thin layers of leather make such a difference?

Click to expand...

I did the same thing with one of mine. The Black SS is too damn soft for me when it is at its original length. It is like bubble gum or a long soft pencil eraser.

I use one on my main playing shaft now but it is about 1/3 the height of what it originally was.

LAMas said:

Assuming the same shaft, a longer separation between the CB and bridge can reduce squirt when hitting the CB off of its center.

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First, thanks for the kind words earlier. I think this has been addressed (i.e., for typical bridge lengths the bridge has zero to negligible effect on squirt).

LAMas said:

With a longer separation, is the end mass reduced because less squirt is produced?

Or, is there more flexing or transverse shaft movement from the bridge that reduces the impact of the shaft and cue tip on the CB thus reducing squirt - effective massl

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A very short bridge (i.e., a few inches) can probably affect (increase) squirt, especially if the shaft lays against a boney part of a finger. But there's no clear division between the types of resistance the shaft puts up to being moved sideways.

That is, near the tip, its resistance is dominated by endmass. As you move down the shaft, there's a gradation into spring-like restoration forces, with the latter becoming dominant at some point. Both types commingle until you get to a location (down the shaft) where only the restoration forces contribute.

I'm basing this on Dr. Dave's description of endmass, which consists of those sections of the shaft that are close enough to the tip such that the reflected waves they generate have enough time to return to the tip during impact.

The diagram I put up earlier in the thread was a bit simplistic:



There is no single point where endmass ends and spring resistance begins. However, measurements and calculations done by Dr. Dave (see TP B.19 here) strongly suggest that endmass is the main factor causing squirt.

From his definition of endmass, it follows that a very short bridge would contribute essentially only to endmass.

Jim

dr_dave said:

Yes I have. That's the kind of "non-human, rigid bridge" that can affect squirt (if the bridge length is less than 8 inches or so), as described on the squirt bridge-length effects resource page.

Regards,
Dave

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This is a simple idea, but why not replace the "rigid bridge" with a fake hand wearing a glove?
Im taking about a molded rubber hand with an articulated skeleton, that can be 'posed' and locked into a bridge.
Even something like an artists poseable hand.

dr_dave said:

I've also wondered if a tall and soft tip could reduce effective endmass (and squirt), not just because of the sideways deformation, but also because it is lighter than the ferrule and shaft wood (i.e., if the tip is taller, the heavier ferrule and shaft will be slightly farther back, which decreases its endmass effect).

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Actually, the sideways deformation would be the only thing that could have an effect since most tips (at least the laminated ones I've measured) have a specific gravity pretty close to 1. The UltraSkins will actually sink slowly in water once you knock the air bubbles off the surface. Since hard maple has a SG of only about .70, the tip adds end mass rather than reducing it.

LAMas said:

Everyone sees what it appears to be but only a few see what it really is...

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There are those that can't see the forest for the trees

dr_dave said:

Concerning the effects of tip elasticity; theoretically, one would think this would have a large effect on tip contact time and resulting squirt; but in reality, with real tips on real cues, the difference in squirt over a wide range of tip types and hardnesses is miniscule (i.e., of no practical significance). For proof, see cue tip hardness effects and the following video:

NV D.15 - Cue and Tip Testing for Cue Ball Deflection (Squirt)

Enjoy,
Dave

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Dr Dave, I got a question thats a bit offtopic but not totally, regarding your comment here above, the effect of tip is miniscule when it comes to deflection you say, but what do you think about it when it comes to curve or swerve or whatever you want to call it, and I am not talking about full on masse shots where you elevate the cue, I'm just talking about swerve in a sense when you shoot the cueball with level cue but total side spin softly, or a bit harder than soft where the cueball would take a curve to the same direction of which you spun the ball to.

dr_dave said:

Yes I have. That's the kind of "non-human, rigid bridge" that can affect squirt (if the bridge length is less than 8 inches or so), as described on the squirt bridge-length effects resource page.

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The bridge length they used on that machine was fairly long, at least 8" by looking at the photos. Also, the top bearing is spring loaded, so it would yield to an upward force. Besides, they made provisions for adding rubber sleeves to the bearings to isolate it from the shaft like a human hand might.

The use of bearings in the design of the jig provided good holding capacity for the shaft without significant increase in friction. The upper bearing of the jig is mounted on a movable spring-controlled bracket which secures free movement of the cue in spite of its taper.

These features of jig design make it possible to simulate the strikes using the so-called closed bridge, when the player’s fingers form a tight grip around the shaft. However, if necessary, this design also allows for simulation of the strikes with open bridge. For this purpose, the bracket and the upper bearing can be removed. In addition to regular bearings, rollers with elastic outer casings can be installed on the jig for imitating soft hand tissues.

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Even then, I'm a bit skeptical that it could add effective end mass since the cue is not attached to it.

They also used a small aluminum clamp with what looks like a neoprene sleeve to clamp the butt into, but even without that cushioning, the clamp assembly can't weigh much more than a heavy weight bolt, unlike the heavy pendulum-type machines I've seen used elsewhere.

It seems like a well thought-out design to me. With a little tweaking here and there, I think it would be a valuable piece of equipment for those engaged in cue testing.

Sloppy Pockets said:

Actually, the sideways deformation would be the only thing that could have an effect since most tips (at least the laminated ones I've measured) have a specific gravity pretty close to 1. The UltraSkins will actually sink slowly in water once you knock the air bubbles off the surface. Since hard maple has a SG of only about .70, the tip adds end mass rather than reducing it.

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That's good to know. I had always assumed the tip was lighter than the ferrule plastic or the shaft wood. Thank you for correcting me.

Dave

asbani said:

dr_dave said:

Concerning the effects of tip elasticity; theoretically, one would think this would have a large effect on tip contact time and resulting squirt; but in reality, with real tips on real cues, the difference in squirt over a wide range of tip types and hardnesses is miniscule (i.e., of no practical significance). For proof, see cue tip hardness effects and the following video:

NV D.15 - Cue and Tip Testing for Cue Ball Deflection (Squirt)

Click to expand...

Dr Dave, I got a question thats a bit offtopic but not totally, regarding your comment here above, the effect of tip is miniscule when it comes to deflection you say, but what do you think about it when it comes to curve or swerve or whatever you want to call it, and I am not talking about full on masse shots where you elevate the cue, I'm just talking about swerve in a sense when you shoot the cueball with level cue but total side spin softly, or a bit harder than soft where the cueball would take a curve to the same direction of which you spun the ball to.

Click to expand...

If the CB is sent in the same direction with the same speed and amount and type of spin, it doesn't matter what tip is used. However, for a given stroke and tip contact point, different tips will yield different results (i.e., CB speed and the effects of swerve can be different). For more info, see the cue-tip hardness-effects resource page.

Regards,
Dave

dr_dave said:

That's good to know. I had always assumed the tip was lighter than the ferrule plastic or the shaft wood. Thank you for correcting me.

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Me too. Thanks for the heads up.

Engineering toolbox give densities of:
Leather, Dry: 0.86 10³kg/m³
Maple: 0.6 - 0.75 10³kg/m³
Phenolic: 1.24 - 1.32 10³kg/m³

Presumably glues and finishes increase that somewhat.

Thank you kindly.

Corwyn_8 said:

Me too. Thanks for the heads up.

Engineering toolbox give densities of:
Leather, Dry: 0.86 10³kg/m³
Maple: 0.6 - 0.75 10³kg/m³
Phenolic: 1.24 - 1.32 10³kg/m³

Presumably glues and finishes increase that somewhat.

Thank you kindly.

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Gotta love Engineering Toolbox, that site saved my butt on many projects in the last few years.

I believe most tips today (at least the desirable ones) are highly compressed leather with proprietary "stuff" added during manufacturing. From Milk Duds to multi-laminate glued-up tips, there is probably plenty of extra solid material in all of them.

I just grabbed several UltraSkins from the softest ("Pro") to the hardest ("HH") and weighed them on my gram scale. They all weigh 1.25 g as they come from the supplier. They are 14mm across and 7.85mm thick, which comes out to around 1.2 cc in volume. Therefore, they all have a SG slightly above 1, or about 50% denser than hard rock shaft maple. I did not expect this result, and wrongly assumed that the hardest tips would be the densest.

Maybe herein lies a reason why many top players claim the tip plays better when it gets very low. Just food for thought from a little brain. Carry on, big brains, this is a fascinating thread. Maybe I'll actually understand it all in due time.

A rather good player in my area bought one of the DyamondWood cues & 'loved' it.

When the tip wore down he began having troubles but not with any real miscues, but it sounded very odd & was not playing the way it had been.

He roughed up the tip but it did not have any real effect.

I was there one day when he was complaining about it, so I asked if he'd like me to try something. He said, 'sure, it can't be any worse'.

I priked the tip with my tip prik & applied a good layer of Blue Diamond Chalk.

It played better, so much so, that he 'stole' my Blue Diamond Chalk.

However, it apparently did not last, as he ultimately traded the cue.

He probably did not keep the tip in a priked condition & allowed it to gloss over.

I do not know what brand or type of tip was on the cue but it obviously did not suit that player when it wore down.

The reason that he bought the DyamondWood cue was because of it's very low squirt with a very solid hit.

The point, to me, is that the tip can be the most important component of any cue to a player...

And the the condition that it is kept in can be just as important.