Squirt. End Mass and Cue Flexibility.

[LAMas]

jsp linked this post by jal from 2007 and is well written and what I was trying to say.


"...Another way of looking at it is that, given the same stick speed, less impulse develops when the cueball is struck off-center than when struck at center. To generate the same impulse, which was Jsp's premise, the cue has to be traveling faster and therefore has more kinetic energy. That's where the additional energy of the cueball comes from.

But why is there less impulse for an off-center hit given the same stick speed?

Impulse (force X time) equals a change in linear momentum (mass X velocity). Newton's third law tells us that during the collision, the impuse acting on the stick is exactly the same as that acting on the ball (same in magnitude but opposite in direction). Compared to a billiard ball, if you strike a ping-pong ball with your cue, the cue's momentum hardly changes. Therefore the impulse which acted on both the stick and the ping-pong ball must be much less. But if you strike a bowling ball, the stick jumps back and undergoes a much larger change in momentum. The impulse on the stick and the bowling ball must therefore be much larger.

When you strike the cueball off-center, it can rotate as well as move forward, ie, it can "get out of the way" easier. In effect, it presents less mass (inertia) to the stick. For the same stick speed then, as per above, less impulse develops...."

Kudos jal.

 

[LAMas]

Back to - Squirt. End mass and cue flexibility.

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

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 mass?

This may have been hashed over and over years ago but there are new inquiring minds.


Be well

 

[ENGLISH!]

Back to - Squirt. End mass and cue flexibility.

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

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 mass?

This may have been hashed over and over years ago but there are new inquiring minds.


Be well

E,

As you know the key word in the phrase "effective end mass" is the word effective.

Over isolation is a problem as I see it, as there is very much going on in that time frame that Renfro/Chris has referred to as 'an eternity'.

If a hard tip yields on average .001 of a second of contact time & a soft tip yields on average double that to .002 of a second (perhaps .004 of a second), of contact time, then that is still a 100% increase in contact time for things to happen... or get accomplished.

That may be a good thing for some & it may be a bad thing for others.

I just think it is rather wrong to say that differences yield no difference & make no difference.

That just makes no sense to me.

You Stay Well.

PS Also the word significant can be a word of relative meaning. Just who decides what is significant & what is insignificant. What is insignificant to one individual may be of considerable significance to another individual. I think each individual should decide for themselves what is significant to them & not rely on or be subject to others for those determinations.

 

[jsp]

Please argue it then. (I am not sure what you are saying).

[In the thread linked to later, the energy is the same, but that alone won't tell you how far it will roll.]

Thank you kindly.

Looking back, I think I may have misinterpreted your post. For some reason I thought the offset you were referring to is on the vertical axis (causing forward roll). I'm pretty sure now that you're referring to the horizontal (side spin), which makes sense since this thread is about squirt. That's what happens when I don't actually follow the entire thread and take a single post out context.

 

[Corwyn_8]

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

Evidence?

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

Taking the assumption above for the sake of argument, a bridge hand could act as an increase in end-mass.


Thank you kindly.

 

[Bob Jewett]

Back to - Squirt. End mass and cue flexibility.

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

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 mass?

This may have been hashed over and over years ago but there are new inquiring minds.


Be well

If the shaft is supported very stiffly and close to the tip, that support structure can add to the effective end mass of the tip. As Dr. Dave has pointed out and probably has a video of, the most extreme case of this is when you shoot a jump shot by sliding the stick along the cloth to hit the bottom of the cue ball. This can be done without a miscue, depending on the diameter of the tip and the chalk. The end mass now includes the table, and the ball squirts up over the object.

The problem of stiff support was also present in the original "Iron Willie" robot tester that Predator used. At the time of the Jacksonville Experiment (Nov 1998) the front of the shaft was held by a stiff metal piece. The butt was held by a very stiff clamp. The problem with the first is the squirt issue. The problem with the second is that a very stiff hold increased the effective weight of the cue stick. I'm told that Predator has since revised the design of Willie.

However, because the hand is of very soft material compared to wood and has flesh padding, it can't give much lateral force when compared to the forces involved with the tip-to-ball contact. If you were to use a heavy brass bridge and it was within 8 inches of the cue ball, then you might start to see an effect.

Previous experiments were done with weights clamped to the stick at various distances from the tip. Longer separation led to less added squirt. Mike Page did one run with vice grips to provide an extreme example. I hope he didn't do it on a Balabushka shaft.

So far as the theory goes, any additional mass or support should increase squirt if it is close enough to the tip.

Squirt could be reduced to almost zero if the tip were on rollers. The design of a practical such system is left as an exercise for the reader.

As for the Rod Cross paper, I didn't notice anything surprising in it. There were several procedural problems. I think hitting the slanted pieces of glass was not useful.

 

[Cornerman]

Evidence?



Taking the assumption above for the sake of argument, a bridge hand could act as an increase in end-mass.


Thank you kindly.

This is the current best theory as it relates to the overall transverse wave concept, but it has plenty of caveats. The bridge hand would have to be abnormally rigid to significantly add any mass.

Maybe if the bone of the knuckles were up tightly against the shaft, and the bridge length is short, then I can see that as potentially significant.

Freddie <~~~ doesn't want to test it

 

[Cornerman]

Squirt could be reduced to almost zero if the tip were on rollers. The design of a practical such system is left as an exercise for the reader.

I'll highlight this because a lot of new poster or new squirt discusses seem to miss this idea as they're too busy with end as as opposed to effective end mass.

If a cue tip is decouple from the shaft during the tip/ball contact time, then thr effective mass contribution from the shaft goes away, and we're left with tip mass only. So decoupling or delaying the rigid coupling is the other method to reduce squirt.

Bob Meucci's ferrule/tenon gap and Jaden's low squirt tip are examples of this.

Freddie <~~~ decoupling from this thread eventually

 

[ENGLISH!]

Perhaps a comparison should not be made between a human hand & a solid brass bridge...

but instead a human hand compared to nothing & no lateral support at all.

Perhaps a cue stroke that can move away with no restriction, like a true swipe, vs one that is held more on line by a human bridge hand...

as opposed to going in the other direction that is not really applicable like a piece of brass or iron as a bridge.

Does a tightly closed bridge where the cue stick runs through 3 'tight' contact points yield a different result compared to an open bridge with a light rear balanced cue just sitting on it & with a very light 'hold' at the rear of the cue vs a tight hold on it that can steer the stick & the tip?

Just some food for thought for anyone so inclined.

PS As I've said, I have a different mind set when using an off center hit for the use of spin vs the use of the squirt. Those different mind sets I think yield a different subconscious performance.

 

[LAMas]

This is the current best theory as it relates to the overall transverse wave concept, but it has plenty of caveats. The bridge hand would have to be abnormally rigid to significantly add any mass.

Maybe if the bone of the knuckles were up tightly against the shaft, and the bridge length is short, then I can see that as potentially significant.

Freddie <~~~ doesn't want to test it

This looks it will work and I wonder if Earl has tried it out?

 

[LAMas]

Perhaps a comparison should not be made between a human hand & a solid brass bridge...

but instead a human hand compared to nothing & no lateral support at all.

Perhaps a cue stroke that can move away with no restriction, like a true swipe, vs one that is held more on line by a human bridge hand...

as opposed to going in the other direction that is not really applicable like a piece of brass or iron as a bridge.

Does a tight closed bridge where the cue stick runs through 3 'tight' contact points yield a different result compared to an open bridge with a light rear balanced cue just sitting on it & with a very light 'hold' at the rear of the cue vs a tight hold on it that can steer the stick & the tip?

Just some food for thought for anyone so inclined.

PS As I've said, I have a different mind set when using an off center hit for the use of spin vs the use of the squirt. Those different mind sets I think yield a different subconscious performance.

Cory Dual was in town a few years ago and was shooting all of his shots with the plastic bridge.
Now if we put linear roller bearings on the base of this bridge.



Be well

 

[LAMas]

If the shaft is supported very stiffly and close to the tip, that support structure can add to the effective end mass of the tip. As Dr. Dave has pointed out and probably has a video of, the most extreme case of this is when you shoot a jump shot by sliding the stick along the cloth to hit the bottom of the cue ball. This can be done without a miscue, depending on the diameter of the tip and the chalk. The end mass now includes the table, and the ball squirts up over the object.

The problem of stiff support was also present in the original "Iron Willie" robot tester that Predator used. At the time of the Jacksonville Experiment (Nov 1998) the front of the shaft was held by a stiff metal piece. The butt was held by a very stiff clamp. The problem with the first is the squirt issue. The problem with the second is that a very stiff hold increased the effective weight of the cue stick. I'm told that Predator has since revised the design of Willie.

However, because the hand is of very soft material compared to wood and has flesh padding, it can't give much lateral force when compared to the forces involved with the tip-to-ball contact. If you were to use a heavy brass bridge and it was within 8 inches of the cue ball, then you might start to see an effect.

Previous experiments were done with weights clamped to the stick at various distances from the tip. Longer separation led to less added squirt. Mike Page did one run with vice grips to provide an extreme example. I hope he didn't do it on a Balabushka shaft.

So far as the theory goes, any additional mass or support should increase squirt if it is close enough to the tip.

Squirt could be reduced to almost zero if the tip were on rollers. The design of a practical such system is left as an exercise for the reader.

As for the Rod Cross paper, I didn't notice anything surprising in it. There were several procedural problems. I think hitting the slanted pieces of glass was not useful.

Thanks for the response Bob.
I always look for them.

I suppose that a pair of neodymium magnets below the leather tip with polished surfaces and with a collar to limit the transverse lateral travel can work.

 

[dr_dave]

If the shaft is supported very stiffly and close to the tip, that support structure can add to the effective end mass of the tip.

For those interested, more info, demonstrations, and video proof related to this can be found on the squirt bridge-length effects resource page.

As Dr. Dave has pointed out and probably has a video of, the most extreme case of this is when you shoot a jump shot by sliding the stick along the cloth to hit the bottom of the cue ball. This can be done without a miscue, depending on the diameter of the tip and the chalk. The end mass now includes the table, and the ball squirts up over the object.

For those interested, here's the video:

HSV B.2 - Illegal "scoop" jump shots

The problem of stiff support was also present in the original "Iron Willie" robot tester that Predator used. At the time of the Jacksonville Experiment (Nov 1998) the front of the shaft was held by a stiff metal piece. The butt was held by a very stiff clamp. The problem with the first is the squirt issue. The problem with the second is that a very stiff hold increased the effective weight of the cue stick. I'm told that Predator has since revised the design of Willie.

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:

squirt-testing robot issues

Previous experiments were done with weights clamped to the stick at various distances from the tip. Longer separation led to less added squirt.

For those interested, Diagram 4 in the following article summarizes results of an experiment like this:

"Squirt - Part VII: cue test machine results" (BD, February, 2008)

Squirt could be reduced to almost zero if the tip were on rollers. The design of a practical such system is left as an exercise for the reader.

Here's a photo from the squirt endmass and stiffness resource page that shows Meucci's attempt at decoupling the tip from the rest of the shaft by allowing the ferrule to flex (with their "Power Piston" design):

Enjoy,
Dave

 

[LAMas]

Is this a Power Piston?



The cue in question is a Meucci Power Piston ...

In spite of its moniker, 'Power Piston,' this is not a power hitter. If you're into blasting away at stuff, this cue probably will not be to your liking, as it is too easy to put unintended english on the CB at higher speeds. This is a finesse shooter, making the most from just the momentum of the cue itself....


However, shooting the same english in practice, the new Meucci puts noticeably more spin on the cue ball than the older regular shafted DH-2.
...
rkim99

http://forums.azbilliards.com/showthread.php?t=108892

 

[Bob Jewett]

... This is a finesse shooter, making the most from just the momentum of the cue itself ...
rkim99

A small nit for the sake of complete clarity....

Experiment shows that the momentum of the cue stick is pretty much the only momentum available when tip hits ball to put the ball into motion. The grip hand is too soft to participate during the brief contact. (iron hands and Iron Willies not included)

 

[Bob Jewett]

Is this a Power Piston? ...

I think it is. I have heard that on extreme power shots the ferrule runs out of lateral space when shimmying sideways, but I've never tried to test that idea. It's not clear to me why you need the last 12mm or so of free-standing tenon in this design.

 

[dr_dave]

Experiment shows that the momentum of the cue stick is pretty much the only momentum available when tip hits ball to put the ball into motion. The grip hand is too soft to participate during the brief contact. (iron hands and Iron Willies not included)

Agreed. For those interested, more info on this topic can be found here:

effects of light vs. tight grip

Enjoy,
Dave

 

[Sloppy Pockets]

Is this a Power Piston?

View attachment 412051

The cue in question is a Meucci Power Piston ...

Interesting. I wonder if a very tall and soft tip moves laterally during the hit in a similar fashion.

 

[dr_dave]

Interesting. I wonder if a very tall and soft tip moves laterally during the hit in a similar fashion.

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).

I've never tested this, but I would think that any effects would be very small. The reason I think this is that when I tested a wide range of tip types and hardnesses (including one of Jaden's prototype tips), there was almost no difference in resulting squirt, as documented in the following video:

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

Enjoy,
Dave

 

[ENGLISH!]

Is this a Power Piston?

View attachment 412051

The cue in question is a Meucci Power Piston ...

In spite of its moniker, 'Power Piston,' this is not a power hitter. If you're into blasting away at stuff, this cue probably will not be to your liking, as it is too easy to put unintended english on the CB at higher speeds. This is a finesse shooter, making the most from just the momentum of the cue itself....


However, shooting the same english in practice, the new Meucci puts noticeably more spin on the cue ball than the older regular shafted DH-2.
...
rkim99

http://forums.azbilliards.com/showthread.php?t=108892

E,

I could be wrong but I am fairly sure that Meucci went to that type of ferrule well before the Power Piston & the term Power Piston is in reference to the Butt & not the shafts.

If one will note in the link you provided the individual was not comparing different shafts on his HP-3. He was comparing the HP-3 butt(& shaft) to the Power Piston butt(& black dot shaft).

Also Meucci made a change in the material that the ferrules were made of, as the 1st. ones were subject to cracking from the 'flexing'. The 2nd. generation was made of a more pliable material to help prevent cracking.

I know you know, but the bowing of the shaft with the tip aiming inward toward the center of the ball is similar to compression which initially delays the brunt of the force being applied...

& then the restoration is applied along with the rest of the force.

Like Al Pacino said as the Coach in the movie, On Any Given Sunday, "...the margin for error is so small...every second, 1/2 second to slow or too fast... you don't quite catch it..."

I've said a few times now how the theory for golf club heads & baseball bats & tennis rackets went away from solid rigidity to finely tuned & timed flex & restoration. The results were so dramatically good that the USGA had to place limits on the COR of club heads & baseball bats had to be similarly restricted for College & High School Competitions although there were balance issues in play also there.

Interestingly the 'aluminum' bat walls also cracked in the old days due to the flexing much like the 1st. generation Meucci ferrules...

Aand John Daly cracked a few driver heads in his day too.

You Stay Well.