Squirt. End Mass and Cue Flexibility.
- Thread starter LAMas
- Start date
ENGLISH,
I posted this description a few pages before you posted the above and I kept thinking about the bolded.
- The tip compresses before the CB moves.
- The compressed tip becomes distorted like being extruded by the accumulating
force of the shaft.
- The CB starts to move or roll forward and rotates CCW while in contact with the compressed tip.
- The front of the shaft follows the tip down - bending from the bridge hand and grip.
I only observed from the 4 picture below that the front of the shaft and ferrule was moving away from the CB after the tip was released from contacting the CB. I assumed that the front of the shaft was moving away (toward the bottom).
With the cue held with the bridge hand and the grip hand, when I thought about it, I assumed that the cue had to bow away from the CB or down in this case with the pivot being the bridge hand and not as you said - pointed toward the center of the CB.
I kept thinking about what you posted for the pictures don't show that at first glance.
Then I wondered what the front of the shaft and ferrule behind the tip was doing while the tip was being compressed and extruded upward. For that instance, the ferrule and shaft was moving down while the tip of the tip was stationary impinged on the surface of the stationary CB - it hadn't moved yet.
So indeed for that instant, the shaft was being bowed toward the center of the CB and not outward away from the center of the CB. Since the pictures don't show the whole cue, that is imperceptible.
If the shaft was stiff enough, then the shear and compressive strength of the shaft would resist any visible bend/bowing and the pictures only show the front of the shaft moving away from the CB after release - that's not to say that your premise didn't happen.
If the shaft was whippy and the CB were nailed to the slate, then if the tip became impinged to the surface of the CB, the bowing toward the center of the CB would been visible.
Most pool players don't dig that deep into the physics of pool but do react and learn from what they observe as I did.
.
Kudos to those that have contributed to this thread though it became esoteric but interesting enough to garner over 8,000 hits
Bravo........ Nuances.... Dismissed variables as inconsequential.... I have said this for several years now and since it doesn't fit what was already posted as truth it was ignored....
Contact time is NOT 1ms.... IT IS ONLY 1MS if you are using phenolic OR you are hitting your test shots at BREAK SPEED to remove swerve...
A tip is a spring so it follows spring dynamics unless you compress it to a solid. Otherwise solid contact collision physics are crap for pool in many instance....
A soft tip can stay on the ball for 4ms or 7+mm of travel... During that time/distance the shaft can be a game changer..... As can a player who has practiced and rehearsed their movements hitting the cueball on time...
Testing pool in a vacuum with less than professional talent is never going to work and all the D players in the world parroting in homage won't help either....even if they have the vids removed.....
I and others (including the Jacksonville Project) have measured tip contact times over a wide range of speeds and tip hardnesses. Here's a summary of what has been found, from the cue tip contact time resource page:
1.) most contact times (i.e., for most tips and most speeds) are very close to a thousandth of a second (0.001 sec).
2.) a soft tip at slow speed has a longer contact time (about 0.002 sec), but still extremely small.
3.) a very hard tip (e.g., phenolic) at fast speed has a shorter contact time (about 0.0005 sec).
4.) the contact time decreases slightly for faster speeds, but not by much.
For more info and access to the sources of info, see the resource page.
Regards,
Dave
This is physically impossible unless the tip can be compressed without any force being applied to it by the ball.
I'm not a scientist, but I believe the tip is compressing as the ball is moving. By how much is for somebody else to figure out.
I know (in my mind, and feel) that a softer tip allows my tip to remain in contact with the cue ball longer than a harder one does. If it DOESN'T, then it is a good placebo that allows me to think that and play better.
Now, back to you scientists.
Aloha
This is actually true, but for the range of typical tip harnesses, it makes almost no difference in how much spin you get on the ball for a particular amount of tip offset from center. As Dr. Dave mentioned above, for leather tips a soft tip might stay on the ball twice as long for a given shot speed.
Amount of spin is only very slightly influenced by contact time.
Hi Jaden,
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?
Thanks in Advance & Best 2 Ya,
Rick
Last edited:
Presumably this is largely dependent on the efficiency of the tip in returning energy used in compression, yes? The stick has only so much momentum that it can give to the ball. In an idealized, perfectly elastic collision, contact time would not be a factor. The spin is mostly determined by that total momentum given to the ball and offset of the contact point from the center of mass. So any differences need to be hiding elsewhere.
Thank you kindly.
I hope that after this huge thread with so much disagreement on basic physics principles, people can at least agree with the following facts:
1.) It takes force to compress a cue tip.
2.) During tip contact with the CB, there is an equal and opposite force acting between the tip and CB as long as the tip is compressed (even if the amount of compression is decreasing, as during the later part of tip contact).
3.) For the entire time the tip is compressed (even during the early part of tip contact, where the amount of compression is small), a force acts on the CB from tip.
4.) For the entire time a force acts on the CB, it will be accelerating forward (i.e., its speed will be increasing); and in the case of an off-center, the amount of sidespin will continue to increase.
Regards,
Dave
That is correct.
You might be correct about the placebo thing, but there is no way a human player could perceive the minuscule differences in contact time between a hard and soft tip (about 0.001 second!).
Now, a soft tip will definitely create a hit that feels different, and the speed and spin delivered to the ball will typically be less for a given stroke and tip contact point. For more info, see:
cue "feel," "hit," "feedback," and "playability"
cue tip hardness effects
cue and tip efficiency
Regards,
Dave
If people doubt this, they should read the cue tip hardness effects resource page. It explains why this is true.
Regards,
Dave
Last edited:
I'm not looking for more spin. I can put all the spin on the ball I need.
I'm looking for "ball FEEL". If I can "feel" the ball more, I can control it better. I don't like the feel of the ball coming off my tip super quick and bouncing around like a Pachinko ball.
I think "feel" is part of what people call "hit".
Aloha
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
Last edited:
Yes, it does change the feel quite a bit. Some people prefer a sharp, quick. "pingy" sort of hit. I suspect it comes down to what you were using the first year or two you played.
Some people think there is a Jesus and some people don't. I don't think "YOU" can determine what "I" think I "feel".
"Whatever" I "think" I "feel" is REAL to ME! Whether it is the "impact" or the "contact time"...the results are the SAME to "ME".
Aloha.
yes...
I was going to just stay out of this thread because at this point I don't see it serving any positive purpose, but yes that would be a good way of putting it.
Jaden
I was going to just stay out of this thread because at this point I don't see it serving any positive purpose, but yes that would be a good way of putting it.
Jaden
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.
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.
Last edited:
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