Cue Tip Contact Myth-Busting Truths in Super Slow Motion

[WobblyStroke]

You see what I'm saying, though. Patrick wants a controlled test.

Hang the cue by some string tied to the butt and shaft, and let gravity do the work. You will be guaranteed to land on the cb at the same spot with the same speed.

There will be no question of grip tightness, deviation of contact point, tip speed, or any other possible deviation.

Moreover, with this method slow speeds are easy to reproduce and quantify...e.g. release the cue 1 inch, 2 inches, ..., 6 inches, ... etc from the cueball.

I get it. your method will produce only shots that fit the criteria to be included.
The method I used and the one PJ suggests allows for some human error in attempts but, since only those attempts which meet the criteria get included in the sample, both samples end up with pretty uniform shots that isolate differences in spin as the variable.

 

[Patrick Johnson]

He said you need a more delicate stroke to get the same spin with a hard tip. Why would you need a more delicate stroke if the tip hardness has negligible effect?

He was obviously referring to the well known fact that harder tips need a slightly slower stroke to produce the same CB speed.

Try reading more slowly.

pj
chgo

 

[garczar]

Just curious as to what DNA make-up one must have to continually make yourself look like a fool in a public setting. I guess we all do it from time to time but the aiming loonies and now these 'tip deniers' are taking it into uncharted territory. Pretty impressive in some ways. Happy Friday folks, i'm hittin balls and havin home-made tamales/queso/cold Yeungling draft today.................

 

[pvc lou]

I get it. your method will produce only shots that fit the criteria to be included.
The method I used and the one PJ suggests allows for some human error in attempts but, since only those attempts which meet the criteria get included in the sample, both samples end up with pretty uniform shots that isolate differences in spin as the variable.

Ok, I suppose I'll allow it if PJ approves.

 

[jollyrodger]

I get it. your method will produce only shots that fit the criteria to be included.
The method I used and the one PJ suggests allows for some human error in attempts but, since only those attempts which meet the criteria get included in the sample, both samples end up with pretty uniform shots that isolate differences in spin as the variable.

i believe the point PVC is making is that you would need a method that is repeatable by anyone. my experience in the scientific community is if the experiment can not be accurately duplicated using the same variables. then the experiment is null. so assumptions can be made. but facts can not be confirmed until it can be duplicated and recreated.

 

[pvc lou]

He was obviously referring to the well known fact that harder tips need a slightly slower stroke to produce the same CB speed.

Try reading more slowly.

pj
chgo

So you admit that speed/spin ratio depends on tip hardness.

 

[Patrick Johnson]

i believe the point PVC is making is that you would need a method that is repeatable by anyone.

What about "don't count any shot that doesn't meet the criteria" isn't repeatable by anyone?

pj
chgo

 

[pvc lou]

What about "don't count any shot that doesn't meet the criteria" isn't repeatable by anyone?

pj
chgo

Your criteria are necessary but not sufficient. You can move the cb the same distance with different tip placements, grip pressure, tip hardness....

Your proposed method is sloppy.

 

[dr_dave]

He said you need a more delicate stroke to get the same spin with a hard tip. Why would you need a more delicate stroke if the tip hardness has negligible effect?

I already explained what that meant, but here goes one last time:

A hard tip usually has a better hit efficiency than a softer tip, so you need to use a slightly slower cue speed to get the same CB speed. The same is true for a heavier cue (see cue weight effects). For those interested in facts and not anecdotes and myths, all of this stuf and more is made clear on the cue tip hardness effects resource page and via all the supporting links on that page. And for people interested in seeing proof debunking many more common pool myths, see:

Top 100 Pool Myths Debunked​

 

[jollyrodger]

What about "don't count any shot that doesn't meet the criteria" isn't repeatable by anyone?

pj
chgo

you still are making the choice of what meets the criteria. so you are possibly introducing human error. all variables that can be different need to be isolated.

i would say the experiment should be ran using

1. same cue for each tip. ( so the weight, deflection and joint time is the same.)
2. same cloth on the table.
3. same table brand.
4. same designated speed for the stroke. ( 2mph, 5mph, 10mph for example )
5. same tip placement on the ball.
6. same location on the table.

i would also add same room temp and moisture level and if not the same then document it and offer it up as a possible factor.

 

[pvc lou]

Just curious as to what DNA make-up one must have to continually make yourself look like a fool in a public setting. I guess we all do it from time to time but the aiming loonies and now these 'tip deniers' are taking it into uncharted territory. Pretty impressive in some ways. Happy Friday folks, i'm hittin balls and havin home-made tamales/queso/cold Yeungling draft today.................

I still like you garczar. I regret saying you gargle Dr. Dave testicle-flavor koolaid. That was not nice, and not the point.

I apologize.

 

[WobblyStroke]

i believe the point PVC is making is that you would need a method that is repeatable by anyone. my experience in the scientific community is if the experiment can not be accurately duplicated using the same variables. then the experiment is null. so assumptions can be made. but facts can not be confirmed until it can be duplicated and confirmed.

True. The jigging up of the cue does remove stroke delivery as a variable between experimenters. However it is the variability within the experiment that is the issue and whether or not, for how you stroke it, if the ball will spin as much/more/less if you control for both speed (by excluding any shot length outside a defined range), and tip offset (confirmed by chalk marks on a marked ball aligned to target for each attempt.

My stroke may very well get more spin with either a soft or hard tip than someone else's, but that isn't all that important as long as the soft and hard tip can be shown to not differ FOR ME. The other experimenter who gets less spin (or more for that matter) than I do will also be paying attention to the results for him comparing only his soft tip attempts to his hard tip attempts.

But the jigged up cue, you are correct, would give more consistent results between different experimenters. While that would be an absolute must component of a study trying to determine exactly how much spin a given speed will put on the ball, it isn't as needed to determine if there is a difference between hard and soft tips bc variability between people swinging the cue don't matter as we are looking for relative differences rather than absolute metrics that apply across all players.

 

[Patrick Johnson]

Your criteria are necessary but not sufficient. You can move the cb the same distance with different tip placements

Then the chalk mark tells you to discard that example.

grip pressure

Nope - no effect.

tip hardness....

As I said above (probably more than once), tip hardness affects spin and speed together in the proportions determined by tip offset.

Your proposed method is sloppy.

Or is it your thinking?

pj
chgo

 

[pvc lou]

I already explained what that meant, but here goes one last time:

A hard tip usually has a better hit efficiency than a softer tip, so you need to use a slightly slower cue speed to get the same CB speed. The same is true for a heavier cue (see cue weight effects). For those interested in facts and not anecdotes and myths, all of this stuf and more is made clear on the cue tip hardness effects resource page and via all the supporting links on that page. And for people interested in seeing proof debunking many more common pool myths, see:

Top 100 Pool Myths Debunked​

I'm glad you brought this up again. In your hit efficiency page, you include Mike Page's objection to your methods, to your credit.

His objection is that varied contact times between hard and soft tips put into question your experimental methods. Here's what he says (quoted from your hit efficiency page):

from Mike Page (in AZB post):

A softer tip might take almost twice as long to compress and decompress against the ball than a hard tip. And this, by itself, doesn’t affect energy transfer at all. But there is some empirical evidence hard tips tend to be a little more elastic (have less energy loss). Also, this is going to be a tip-to-tip thing. It is not like here is anything automatic about softer tips that make them less elastic.
For the cueball to “feel” the entire weight of the cue, the tip-ball collision has to last long enough for the signal the collision is in progress to travel back and forth across the stick a sufficient number of times. So at some point as we get harder and harder tips, the cueball might not feel the full weight of the cue.
This is a little like a fast-moving train hitting a car that is on the tracks. The car will be launched with a speed characteristic of being hit by just the engine or the engine plus the first couple of cars. The collision time would have to be longer for the car to feel the weight of the rest of the train cars as they crush across the couplings.

 

[Cornerman]

You guys...seriously. Your Doctor conceded the point already...a couple of times.

Here's one:

He said you need a more delicate stroke to get the same spin with a hard tip. Why would you need a more delicate stroke if the tip hardness has negligible effect?

I think you’re better than this. You’ve changed the argument, so there’s no reply that will make sense. The question was whether or not a softer tip produces more spin. All experiments and physics theories say that it’s not true.

That said, a hard tip will have more energy transfer, but that energy is transferred both linearly and rotationally. So there is no more or less spin, but the cueball got more speed (linearly and rotationally). So theoretically, your speed control on finesse and slow shots will need a slower stroke with the hard tip, and therefore one needs to be “more delicate.”

If you want to have a different definition of “spin,” then have at it. Just be clear on your definition.

 

[Patrick Johnson]

you still are making the choice of what meets the criteria.

Chalk mark in same place.
CB travels same distance.
CB returns to same place on near rail.

Do you have trouble seeing things like this accurately?

pj
chgo

 

[pvc lou]

Then the chalk mark tells you to discard that example.

Do you get a chalk mark at slow speed?

Nope - no effect.

Grip pressure most definitely has an effect.

As I said above (probably more than once), tip hardness affects spin and speed together in the proportions determined by tip offset.

You did say that, but that's not the question. I'll remind you: Why a more delicate stroke for a harder tip?

Or is it your thinking?

pj
chgo

I don't think so.

 

[jollyrodger]

True. The jigging up of the cue does remove stroke delivery as a variable between experimenters. However it is the variability within the experiment that is the issue and whether or not, for how you stroke it, if the ball will spin as much/more/less if you control for both speed (by excluding any shot length outside a defined range), and tip offset (confirmed by chalk marks on a marked ball aligned to target for each attempt.

My stroke may very well get more spin with either a soft or hard tip than someone else's, but that isn't all that important as long as the soft and hard tip can be shown to not differ FOR ME. The other experimenter who gets less spin (or more for that matter) than I do will also be paying attention to the results for him comparing only his soft tip attempts to his hard tip attempts.

But the jigged up cue, you are correct, would give more consistent results between different experimenters. While that would be an absolute must component of a study trying to determine exactly how much spin a given speed will put on the ball, it isn't as needed to determine if there is a difference between hard and soft tips bc variability between people swinging the cue don't matter as we are looking for relative differences rather than absolute metrics that apply across all players.

i think we are getting closer to agreeing lol . i have seen people stroke through the cue ball and jab at it. my assumption is that would also affect spin.


Also i just though another variable. are we talking new tip or old tip? because overtime leather absorbs moisture wouldn't that affect the effect of the cue tip on the cue ball?

 

[pvc lou]

I think you’re better than this. You’ve changed the argument, so there’s no reply that will make sense. The question was whether or not a softer tip produces more spin. All experiments and physics theories say that it’s not true.

In the words of the Doctor, "This is simply false."

That said, a hard tip will have more energy transfer, but that energy is transferred both linearly and rotationally. So there is no more or less spin, but the cueball got more speed (linearly and rotationally). So theoretically, your speed control on finesse and snow shots will have less range, and therefore one needs to be “more delicate.”

If you want to have a different definition of “spin,” then have at it. Just be clear on your definition.

With all due respect, energy transfer is a function of the coefficient of restitution (COR), and if you go to the Doctor's archives, you will see that he found the COR to depend on tip hardness.

Let's try to be consistent.

 

[pvc lou]

Science is hard, you guyz.