Squirt. End Mass and Cue Flexibility.

[Jaden]

That's one of the things I haven't understood.

I think it should be pointed out that like Renfro Chris has said, even if the 'feel' of a specific shot is reaching us after the fact...

it is that (after the fact) 'feel' that we as human beings use as references for future strokes.

We learn what that shot 'felt' like & we can then strive to replicate it if that is what we desire to do...or... try to make a change to not replicate a 'bad feeling one'.

A soft forged iron golf club head gives better feedback than a hard cast iron head.

More time equals more 'feeling'.

The same to some extent can be said for a 'soft flex' golf club shaft relative to one's swing speed over one that it too stiff for their swing speed.

I know that the analogies of golf are not exact.

Just some food for thought for anyone so inclined.

It has to do with the timing of contact & where it is in the golf swing or... the cue stroke.

People say that the contact time is too minute to feel a difference. Yet, in the same breath state that the contact time between a soft tip and a hard tip can be 100% more for the soft tip.

I think we can agree that you can feel a hit. If you can feel a hit and the tip can make a 100% difference in contact time, then how can you argue that you can't feel that difference regardless of how short in duration the contact actually is?

I mean have any blind studies been done to see if people can tell the difference between a soft hitting tip and a hard hitting tip without knowing which is which?

If so, and they CAN tell which is which, then what difference would they be feeling if not the contact time? What other difference is there between a hard tip and a soft tip? A softer tip absorbs more of the energy so less is transferred to the ball, but that is what actually increases the contact time is it not?

Also, different people will be able to perceive differences different than others. I know mechanics that can listen to an engine and tell you that a valve is bad and which valve is bad. I know people that can look at something and tell it is a .001 of an inch off of spec. These are outside of the norm, but they do exist.

Jaden

 

[Jaden]

yes because the leather is softer than the resin of the ball.

The ball's mass and inertia (it is the natural tendency of objects to resist changes in their state of motion. This tendency to resist changes in their state of motion is described as inertia) must be overcome during the compression of the tip to make it move. At first contact, where the chalk makes contact before the fluff on the surface of the leather tip is initially compressed, there may not be enough force to move the CB.

This is just for an instant and perhaps not worth mentioning but I can press my thumb up against a solid steel wall and not make it move though my thumb will be compressed to some degree.

Be well

Of course this is true, because the leather of the tip is softer than the material of the ball, it will begin to compress before the ball starts to move. The softer material will give prior to the harder material reacting to the force.

The force will take the path of least resistance, which in this case is the leather compressing. Once the leather has compressed to the point that enough force is imparted to the ball to overcome the inertia that the ball's mass has at rest, THEN it will start to move.

Jaden

 

[DTL]

................

 

[ENGLISH!]

People say that the contact time is too minute to feel a difference. Yet, in the same breath state that the contact time between a soft tip and a hard tip can be 100% more for the soft tip.

I think we can agree that you can feel a hit. If you can feel a hit and the tip can make a 100% difference in contact time, then how can you argue that you can't feel that difference regardless of how short in duration the contact actually is?

I mean have any blind studies been done to see if people can tell the difference between a soft hitting tip and a hard hitting tip without knowing which is which?

If so, and they CAN tell which is which, then what difference would they be feeling if not the contact time? What other difference is there between a hard tip and a soft tip? A softer tip absorbs more of the energy so less is transferred to the ball, but that is what actually increases the contact time is it not?

Also, different people will be able to perceive differences different than others. I know mechanics that can listen to an engine and tell you that a valve is bad and which valve is bad. I know people that can look at something and tell it is a .001 of an inch off of spec. These are outside of the norm, but they do exist.

Jaden

Jaden,

I agree. As I have said Raymond Floyd can feel the difference of one layer of tape under a golf grip. I can't feel a difference until it's 3 layers.

John Havlechek (spelling?) could shoot a few warm up shots & tell a referee if the goal was 1/2 inch too high or too low. I could probably not tell until it was 3 inches off or more.

I played Friday with an OB Pro shaft with a Kamui Medium tip & then changed to an OB Pro shaft with a G2 soft tip.

The difference can be felt & seen in the effects on shots that I was throwing with spin.

Differences yield differences. Some can discern differences & some can not.

Best 2 Ya,
Rick

PS They say Ray Charlse could tell what trumpet in a large orchestra was flat or sharp.

 

[HawaiianEye]

I won't mention any names, but I know at least ONE custom cue maker that almost EVERYONE knows who says the material of the joint is a MAJOR factor in how a cue "hits" and "feels" and there are OTHER people and cue makers who say you CAN'T tell the difference.

SOMEBODY DON'T KNOW WHAT THE HELL THEY ARE TALKING ABOUT!

WHICH IS WHICH?

 

[dr_dave]

With a softer tip, you are not feeling the CB staying on the tip longer. As I mentioned before, that's impossible. What you are actually feeling is less impact in your grip hand since the tip is deadening the hit some and producing less CB speed for the same stroke. I can see how some players might prefer this type of hit.

For more info and further explanations, see:

cue "feel," "hit," "feedback," and "playability"

cue tip hardness effects

cue and tip efficiency

Enjoy,
Dave

I don't think "YOU" can determine what "I" think I "feel".

You are correct. I cannot determine what you "feel" emotionally or how you individually interpret what you are "feeling" physically. My post dealt with the physical sensation, not with how you perceive or interpret it.

Regards,
Dave

 

[dr_dave]

the tension that is built up in the shaft temporarily bows the shaft outward so that as the ball accelerates away from the tip, the bowed tension in the shaft is released and the front of the shaft and tip travels laterally away from the ball due to the release of this tension.

Do you think saying the tip 'swipes' laterally away from the ball due to the 'recoil' of the loaded shaft...

would be an appropriate means of distinction vs saying it is 'deflected' or pushed away by the ball?

yes that would be a good way of putting it.

The flex of the very end of the shaft is a result of the force between the tip and ball. It is not what causes the force.

Again, here are some excerpts from the squirt endmass and stiffness effects resource page that illustrate and explain this:

The force between the tip and CB acts equal and opposite on each object. The CB speed is in the direction of this total force. The CB spin is created since the force's line of action acts at a tip offset relative to CB center, creating a moment or torque. The equal and opposite force on the cue tip also acts off-center on the end of the shaft, creating a bending moment or torque. This is what causes the end of the shaft to flex.

Notice how the force from the tip pushes in the direction the CB heads (i.e., the force arrow is parallel to the speed arrow). This force has two components. One component acts to the right (in the diagram) on the CB and to the left (in the diagram) on the tip. This component is what pushes the CB forward in the line of aim of the shot, and causes the end of the shaft to flex as shown in the diagram (because the force acts off center on the tip). The other force component acts down (in the diagram) on the CB and up (in the diagram) on the tip. This component is what causes CB deflection (squirt) and causes the end of the shaft to gain momentum (speed) away from the CB (up in the diagram) that causes the shaft to flex out. This outward flex starts during tip contact (as the CB rotates during contact and pushes the tip away, as described and illustrated on the what causes squirt resource page) and continues after tip release due to the momentum imparted during tip contact.

Acceleration (an increase in speed) can occur only with force; therefore, the CB can accelerate only while force is acting from the tip. Likewise, the tip and shaft can't be given lateral speed, unless lateral forces are acting (during tip contact). The tip/shaft moves away laterally after the tip leaves the CB because the tip/shaft was given lateral speed during contact (while lateral forces were acting). It is the momentum (mass * speed) of the endmass that makes the tip and shaft move away from the CB after impact. Now, any flex energy still stored in the end of the shaft after tip release will also cause some post-release vibration (as is evident in the slow motion videos on the cue vibration resource page), but this is independent of (and much smaller in amplitude than) the larger-scale tip/shaft motion away from the ball (due to the endmass lateral momentum), as is evident on the what causes squirt and cue vibration pages. Below are some stills from a super-slow-motion video showing of motion of the tip, CB, and shaft evolve during and just after contact. The red line marks the initial position of the top of the shaft and initial tip contact point, and the red dot marks the initial position of a distinct point on the ball. They are in the same positions in each successive image. It is clear that the tip and shaft move down (laterally) away from the CB as the CB moves forward with increasing speed and spin during the entire period of tip contact.

 

[Jaden]

Who has said, it's what CAUSES the force???

The flex of the very end of the shaft is a result of the force between the tip and ball. It is not what causes the force.

Again, here are some excerpts from the squirt endmass and stiffness effects resource page that illustrate and explain this:

The force between the tip and CB acts equal and opposite on each object. The CB speed is in the direction of this total force. The CB spin is created since the force's line of action acts at a tip offset relative to CB center, creating a moment or torque. The equal and opposite force on the cue tip also acts off-center on the end of the shaft, creating a bending moment or torque. This is what causes the end of the shaft to flex.

Notice how the force from the tip pushes in the direction the CB heads (i.e., the force arrow is parallel to the speed arrow). This force has two components. One component acts to the right (in the diagram) on the CB and to the left (in the diagram) on the tip. This component is what pushes the CB forward in the line of aim of the shot, and causes the end of the shaft to flex as shown in the diagram (because the force acts off center on the tip). The other force component acts down (in the diagram) on the CB and up (in the diagram) on the tip. This component is what causes CB deflection (squirt) and causes the end of the shaft to gain momentum (speed) away from the CB (up in the diagram) that causes the shaft to flex out. This outward flex starts during tip contact (as the CB rotates during contact and pushes the tip away, as described and illustrated on the what causes squirt resource page) and continues after tip release due to the momentum imparted during tip contact.

Acceleration (an increase in speed) can occur only with force; therefore, the CB can accelerate only while force is acting from the tip. Likewise, the tip and shaft can't be given lateral speed, unless lateral forces are acting (during tip contact). The tip/shaft moves away laterally after the tip leaves the CB because the tip/shaft was given lateral speed during contact (while lateral forces were acting). It is the momentum (mass * speed) of the endmass that makes the tip and shaft move away from the CB after impact. Now, any flex energy still stored in the end of the shaft after tip release will also cause some post-release vibration (as is evident in the slow motion videos on the cue vibration resource page), but this is independent of (and much smaller in amplitude than) the larger-scale tip/shaft motion away from the ball (due to the endmass lateral momentum), as is evident on the what causes squirt and cue vibration pages. Below are some stills from a super-slow-motion video showing of motion of the tip, CB, and shaft evolve during and just after contact. The red line marks the initial position of the top of the shaft and initial tip contact point, and the red dot marks the initial position of a distinct point on the ball. They are in the same positions in each successive image. It is clear that the tip and shaft move down (laterally) away from the CB as the CB moves forward with increasing speed and spin during the entire period of tip contact.

The cause of the force is the arm swinging the cue and the masses of the cue and the ball interacting with each other.

You seem to be under the false impression that force is being imparted during the entirety of tip contact, but it's not. It's only being imparted while the tip is being compressed. As soon as the tip starts to decompress, the force ceases to be imparted between the ball and the tip/shaft. At least any force that imparts forward motion to the ball ceases at that point. The tip MIGHT be imparting lateral force to the BALL, but the ball definitely isn't imparting any lateral force to the tip/shaft.

Jaden

 

[john coloccia]

Of course this is true, because the leather of the tip is softer than the material of the ball, it will begin to compress before the ball starts to move. The softer material will give prior to the harder material reacting to the force.

The force will take the path of least resistance, which in this case is the leather compressing. Once the leather has compressed to the point that enough force is imparted to the ball to overcome the inertia that the ball's mass has at rest, THEN it will start to move.

Jaden

a=(1/m)F...there is no inertia term in the equation. Acceleration is proportional to force. You need to consider that there is static friction preventing the cue ball from moving instantly, but this is completely different than your inertia mechanism. It will still deform, push on the cloth/table/earth whatever. It doesn't just sit there waiting for some inertial force to be overcome.

This doesn't even have anything to do with tips and cue balls at this point. If your claim is that the whole of classical physics going back to Galileo is completely wrong, it's going to be difficult to talk about it.

 

[dr_dave]

People say that the contact time is too minute to feel a difference. Yet, in the same breath state that the contact time between a soft tip and a hard tip can be 100% more for the soft tip.

I think we can agree that you can feel a hit. If you can feel a hit and the tip can make a 100% difference in contact time, then how can you argue that you can't feel that difference regardless of how short in duration the contact actually is?

I mean have any blind studies been done to see if people can tell the difference between a soft hitting tip and a hard hitting tip without knowing which is which?

I don't think a study is required to determine if people can tell the difference between the hits of soft and hard tips. There are obviously major differences, and people can definitely feel the difference. A softer tip creates many different effects that can be felt directly, but change in contact time is not one of them. Even with a 1000% change in contact time (from 0.001 to 0.010 seconds), I don't think it would be possible for a human to detect or notice such a tiny change in time.

What other difference is there between a hard tip and a soft tip?

There are several detectable differences between a hard and soft tip. A softer tip generally (but not necessarily) has a lower hit efficiency. This can definitely be noticed by a player. A softer tip also transmits impact and vibrations into the cue in a very different way. This can most definitely be felt by the player. These and other things a player can notice and/or feel care described on the following resource pages:

cue tip hardness effects

cue "feel," "hit," "feedback," and "playability"

Regards,
Dave

 

[HawaiianEye]

You are correct. I cannot determine what you "feel" emotionally or how you individually interpret what you are "feeling" physically. My post dealt with the physical sensation, not with how you perceive or interpret it.

Regards,
Dave

When you become a MEDICAL DOCTOR, please let me know.

I can feel a hair barely touch my skin when other people can't feel one touch theirs. You believe and teach what you want. This isn't a knock, it is one opinion vs another.

My brother has a PHD also and he has 1,000 other PHDs that will tell him his version of whatever is not correct.

The same as the economy...there are a thousand economists that will tell you that you can spend your way out of debt. There are others that will say you have to pay your bills before you are completely bankrupt.

I don't have any money, so neither matters to me.

Aloha.

 

[Corwyn_8]

If I can "feel" the ball more, I can control it better.

Can we unpack that statement a bit?
1) When you say you can control it better, are you talking about subsequent shots? Or are you saying that you "feel" the shot, make a decision, and change something?

2) What aspects of the cue ball trajectory are you controlling, based on that feel?

3) I can understand "different" feel, but I have no idea what "more" feel means (in this context). Can you describe?

Thank you kindly.

 

[Jaden]

are you stupid?

a=(1/m)F...there is no inertia term in the equation. Acceleration is proportional to force. You need to consider that there is static friction preventing the cue ball from moving instantly, but this is completely different than your inertia mechanism. It will still deform, push on the cloth/table/earth whatever. It doesn't just sit there waiting for some inertial force to be overcome.

This doesn't even have anything to do with tips and cue balls at this point. If your claim is that the whole of classical physics going back to Galileo is completely wrong, it's going to be difficult to talk about it.

I'm being serious...

For any mass to be MOVED, there HAS to be enough force to move it.

If the force necessary to move it is less than the force it takes to deform the tip, guess what? the tip will deform prior to the mass being moved.

This is because of inertia preventing the object with mass from moving until acted upon by enough force to move its mass. You don't have to factor in any calculation for inertia just like you don't have to factor in any calculation for gravity even though gravity is what is holding the objects to the table.

If you can't even see that, then you need to give up now.

Jaden

 

[john coloccia]

I'm being serious...

For any mass to be MOVED, there HAS to be enough force to move it.

If the force necessary to move it is less than the force it takes to deform the tip, guess what? the tip will deform prior to the mass being moved.

This is because of inertia preventing the object with mass from moving until acted upon by enough force to move its mass. You don't have to factor in any calculation for inertia just like you don't have to factor in any calculation for gravity even though gravity is what is holding the objects to the table.

If you can't even see that, then you need to give up now.

Jaden

So if you neglect friction, and you push on something but you don't push hard enough to overcome inertia, it doesn't move?

 

[Corwyn_8]

As nice as these still images are, go look at the original video. The bend in the stick is immediately apparent in the video, even though it is not obvious in the stills.

Thank you kindly.

 

[Bob Jewett]

... You seem to be under the false impression that force is being imparted during the entirety of tip contact, but it's not. It's only being imparted while the tip is being compressed. As soon as the tip starts to decompress, the force ceases to be imparted between the ball and the tip/shaft. ...

This statement is completely wrong. The cue ball and the stick are moving at the same speed at the end of the compression (at the instant when it turns into decompression). I hope this much is obvious to everyone. If the tip suddenly stopped pressing against the ball as decompression started, the two objects would continue to move forward at that speed together.

What is actually observed -- on a whole bunch of high-speed videos that are available on-line for free -- is that the ball leaves the tip very quickly. In fact careful measurements show that the speed of the cue stick is about 50% of its initial speed just after the ball leaves the tip and the speed of the ball is about 140% of the initial speed of the cue stick. (The actual ratios vary a little due to the tip and the weight of the stick.)

You don't see Jaden's claim in the real world.

 

[Corwyn_8]

You seem to be under the false impression that force is being imparted during the entirety of tip contact, but it's not. It's only being imparted while the tip is being compressed. As soon as the tip starts to decompress, the force ceases to be imparted between the ball and the tip/shaft.

Given that how do you explain a rubber ball hitting the floor and bouncing back up. If no force is being applied as the ball decompresses how does it move?

Thank you kindly.

 

[Jaden]

you still haven't answered the question...

This statement is completely wrong. The cue ball and the stick are moving at the same speed at the end of the compression (at the instant when it turns into decompression). I hope this much is obvious to everyone. If the tip suddenly stopped pressing against the ball as decompression started, the two objects would continue to move forward at that speed together.

What is actually observed -- on a whole bunch of high-speed videos that are available on-line for free -- is that the ball leaves the tip very quickly. In fact careful measurements show that the speed of the cue stick is about 50% of its initial speed just after the ball leaves the tip and the speed of the ball is about 140% of the initial speed of the cue stick. (The actual ratios vary a little due to the tip and the weight of the stick.)

You don't see Jaden's claim in the real world.

How does an object that is moving away from another object receive force from that object?

If the tip is decompressing, the ball is moving away faster than it, there is no objectivity to that statement. It is FACT.

So again, how does an object impart force to an object that is moving away from it?

Jaden

 

[Corwyn_8]

I'm being serious...

For any mass to be MOVED, there HAS to be enough force to move it.

How much force is required to move a single electron? A cueball isn't a single thing. It is a collection of a HUGE number of things. Each of which acts on it's own.

Or looking it another way F=ma. If some mass is not accelerating, then there is NO force.

Thank you kindly.

 

[Bob Jewett]

...
For any mass to be MOVED, there HAS to be enough force to move it.

Do you understand the formula F=ma or the equivalent a=F/m? If you were to understand that formula, you would realize that any force will cause movement.

As for friction of the ball on the cloth, there are two points that prevent it from being important in this discussion. The first is that is it only about 1 ounce. How much tip compression do you get if you balance an ounce weight on your tip?

The second is that the friction from the cloth acts on the bottom of the ball. If you hit the ball in the middle, it is free to rotate even if the bottom is stuck to the cloth. The ball will begin to move even with a force smaller than the static friction at the base of the ball. Here's a related experiment. Open a door half way. Now push gently in the middle of the door. Even with infinite friction on one end (the hinge), the door moves.