Cue Tip Contact Myth-Busting Truths in Super Slow Motion

dr_dave

dr_dave

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FYI, I just posted a new video that busts many common myths concerning what happens when a cue tip hits a cue ball. Everything is supported by super-slow-motion high-speed-camera footage. Check it out:


Contents:
0:00 - Intro
0:10 - Myth 1 – Tip Contact Time
0:48 - Myth 2 – Control During Contact
2:07 - Myth 3 – Tip Hardness Effects
3:16 - Myth 4 – Shot Speed Effects
4:23 - Myth 5 – Miscues
5:42 - Myth 6 – Sliding Contact
6:29 - Wrap Up
6:45 - ---- clip montage

Here's the follow-up video that answers many questions and settles most arguments brought up in this thread:


The new video presents a simple test that anybody can easily do on their own to compare any tips of interest. I first cover all effects associated with using tips of different hardness. I then show careful tests to compare functional performance of tips over a wide range of hardness including a Victory Soft, a medium-hardness Tiger Sniper, and a hard phenolic-like BK Hybrid.

Contents:
0:00 - Intro
0:45 - “Hit” Differences
1:59 - Energy Transfer
3:13 - Sidespin Persistence
3:59 - Drag Effects
5:27 - Cue Elevation Effects
7:05 - CB Deflection
8:06 - Max Spin at Fast Speed
11:14 - Max Spin at Slow Speed
13:01 - Wrap Up


Here's anther follow-up video showing how effective the phenolic-tip break cue is with power draw shots (and not so much with large-curve massé):


Contents:
0:00 - Intro
1:12 - Power Draw
2:54 - Large Curve Massé
4:42 - Wrap Up

As always, I look forward to your feedback, comments, questions, complaints, and requests.

Enjoy!
 
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Great video showing the myth is busted.

What is not clear is if more cue tip contact time is desirable or not.
 
garczar said:
Only drawback i see is you're gonna have a bunch of keyboard kowboys wanting super-slo mo on every match so they can call foul on miscues. ;) Great info here. Blows away a lot of pool's versions of 'old wives tales'.
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Since every miscue involves sliding contact and pretty much always involves multiple secondary hits, miscues should probably be fouls. But then people would want to call a foul on any shot that sounds funny (like a “partial miscue” shot).
 
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dr_dave said:
FYI, I just posted a new video that busts many common myths concerning what happens when a cue tip hits a cue ball. Everything is supported by super-slow-motion high-speed-camera footage. Check it out:


Contents:
0:00 - Intro
0:10 - Myth 1 – Tip Contact Time
0:48 - Myth 2 – Control During Contact
2:07 - Myth 3 – Tip Hardness Effects
3:16 - Myth 4 – Shot Speed Effects
4:23 - Myth 5 – Miscues
5:42 - Myth 6 – Sliding Contact
6:29 - Wrap Up
6:45 - ---- clip montage

As always, I look forward to your feedback, comments, questions, complaints, and requests.

Enjoy!
Click to expand...
Great stuff. Unfortunately, you’ll open up to comments that say that you somehow proved that a softer tip yields more spin because of the increased contact time.
 
Patrick Johnson said:
Is the "amount of spin" measured by the total span of (changing) tip offset during contact - like, say, the average or maximum offset?

pj
chgo
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That’s not the direction those people who believe “more contact time equals more spin.” They typically believe there is some kind of energy juicing going on in that additional contact time, like spinning a basketball on one’s finger. Maximum offset favors the harder tips.
 
Patrick Johnson said:
Is the "amount of spin" measured by the total span of (changing) tip offset during contact - like, say, the average or maximum offset?
Click to expand...
Cornerman said:
That’s not the direction those people who believe “more contact time equals more spin.”
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I know it's not their argument, and that it doesn't matter much either way - I'm just curious about the real physics.

Cornerman said:
Maximum offset favors the harder tips.
Click to expand...
How so?

pj <- learning
chgo
 
Patrick Johnson said:
I know it's not their argument, and that it doesn't matter much either way - I'm just curious about the real physics.
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I think it’s fair to say that the spin is basically the torque equation. Force x offset minus efficiency losses. Because it’s not a single offset due to the the cueball rotating while in contact, there is some averaging of force and offset. Maybe for most shots at initial X speed and Y offset, the soft tip might ride a little farther around, which would give a larger average offset. But that has to be a small increase considering the tip contact loss of speed and efficiency right at the end of contact.


Patrick Johnson said:
How so?

pj <- learning
chgo
Click to expand...
Any tip has a maximum offset before miscuing. Because the soft tip rides longer, then it’s maximum offset would theoretically be slightly less than the maximum initial offset of a harder tip since the softer tip will hit that miscue limit at a slightly less initial offset.
 
Cornerman said:
I think it’s fair to say that the spin is basically the torque equation. Force x offset minus efficiency losses. Because it’s not a single offset due to the the cueball rotating while in contact, there is some averaging of force and offset. Maybe for most shots at initial X speed and Y offset, the soft tip might ride a little farther around, which would give a larger average offset. But that has to be a small increase considering the tip contact loss of speed and efficiency right at the end of contact.



Any tip has a maximum offset before miscuing. Because the soft tip rides longer, then it’s maximum offset would theoretically be slightly less than the maximum initial offset of a harder tip since the softer tip will hit that miscue limit at a slightly less initial offset.
Click to expand...
Thanks, Freddy - appreciate the tuition-free education.

pj
chgo
 
Cornerman said:
I think it’s fair to say that the spin is basically the torque equation. Force x offset minus efficiency losses. Because it’s not a single offset due to the the cueball rotating while in contact, there is some averaging of force and offset. Maybe for most shots at initial X speed and Y offset, the soft tip might ride a little farther around, which would give a larger average offset. But that has to be a small increase considering the tip contact loss of speed and efficiency right at the end of contact.



Any tip has a maximum offset before miscuing. Because the soft tip rides longer, then it’s maximum offset would theoretically be slightly less than the maximum initial offset of a harder tip since the softer tip will hit that miscue limit at a slightly less initial offset.
Click to expand...

Well stated. With a longer contact time, there is also a greater chance of a late miscue at large tip offsets.

Edit: I see now that you said this here. With your two posts, you covered all the bases vey well. When I find some time, I’ll look at adding your quotes to the resource pages if the pages don’t already have all the points covered.
 
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Your conclusion that the difference in tip contact tip time has no variance on how much spin/speed is imparted on the cue ball needs to be supported with evidence. You have not included any evidence, in this video or in previous videos to make such a claim. You claim that just the numbers are so minuscule that they can’t possibly have any effect. That needs to be supported with evidence to back up that claim.

You need to make a video show casing the spin:speed relation to a set cue speed. Because the math says there has to be a variable in the contact time to produce those variances. A BKRush is supposed to have a 93% CoR. A soft hitting Meucci or McDermott may only have 70% CoR. That variance is shown in your video in the contact time. Something smells funny about your conclusions.
 
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