The math says there’s a variable too large to be dismissed. You can keep drinking your koolaid thinking you’re Mr cool around here. The variance between the tip contact from .8ms to 1.9ms is too large to let it slide. You cannot tell me a 100% increase in contact time is negligible, and a non factor. There has to been more variables at play that are being dismissed.
Cue Tip Contact Myth-Busting Truths in Super Slow Motion
- Thread starter dr_dave
- Start date
The amount of variation isn't "math".
It has already been explained why the result doesn't change much - lower force x longer contact = similar result. That's the math.
pj
chgo
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COR has little or nothing to do with contact time or amount of spin imparted. A softer tip does have less hit efficiency (i.e., more cue speed is required to get the same CB speed) and a different feel/sound, but when the CB is hit with a give tip offset, and the CB is given the desired speed, there is not difference is spin between a soft and hard tip. I am working on a resource page that will thoroughly and convincingly answer all the questions and mythical statements that keep re-appearing in this thread and on YouTube and Facebook. I'll post a link when it is available. In the meantime, you and others can find answers here:
The difference is not negligible. It just isn't important per the explanations here:
Thanks for sharing this great video information. It seemed like in the earlier part of the video there was no chalk on the tip. I am wondering when putting English on the ball with chalk does it grab the ball longer than your center ball hits with no chalk. That would make a good video and maybe explain why we feel like a softer tip stays on the cue ball longer. Maybe it will prove our brains just interpret more grab as staying in contact longer. Or maybe our brains can tell the difference of several tenths of a thousandth of a second.
Yes, (Lower torque) x (longer contact) = same change in angular momentum. This is a simplification of an integral equation:
Integral of the time dependent torque applied over the duration of the impact = the change in angular momentum.
Measuring this applied torque in real time is a challenge, I think. I don't know how to probe it. So Bob, the engineer who's name escapes me now, and Doctor Dave have made the simplifying assumption that the average applied torque from a soft tip is small enough to compensate the increased duration of the impact so that you get the same change in angular momentum. This is assumed, not demonstrated. I think it can legitimately remain an open question.
I suggested a simple test that might isolate tip hardness as the only variable by taking the two extremes (hard/soft) and controlling for surface roughness. This might allow some more reliable evaluation of this assumption without using micro-accelerometers or whatever for measuring the real-time dynamics which occur on very short time-scales. I have my doubts that the tests proposed span the gamut of possible effects of tip hardness on cb spin enough to declare the "myth busted."
So much happens in the 1-2 milliseconds of impact that these simplifying assumptions have to be checked.
Amen to that.
BTW, it doesn't.
If anything, a hard tip has a better chance to impart more spin (for a given CB speed); although, the difference is too small to be important.
For those interested in improving their understanding of the facts, all the links I provided above provide convincing justification.
The part in bold I find very hard to believe. Do you expect my thick rubber tip will impart (slightly) less spin than a hard plastic tip with a very thin coating of the same rubber?
You do the measurements, and I'll bet you $100 that it doesn't go that way.
(Quick edit: I just noticed your caveat "for a given CB speed." Not sure if you meant to be slick, but I'll give you the benefit of the doubt. I'll assume you meant cue-stick speed. This is what the test is really about.)
This applies to anything about pool. We should be able to have civil discussions without things ratcheting out of control. I understand the reasons but I think it ridiculous that we have to have a separate forum for aiming on a pool site. Then I read some aiming discussions are banned even on the aiming forum!
Absolutely no reason to get bent out of shape when we disagree on technical subjects. I disagree about points here and there, some things I think just aren't adequately proven. Sometimes tests in one area disprove claims made in others also. Ultimately much of these discussions have about the same effect on our pool performance as how many angels can stand on a pin.(that answer varies depending on if you allow the angels on the outside to stand on one foot. Fat angels really screw up the answer too!)
Hu
The real physics would have to be tested with identical cues (one with a hard tip and one with a super soft tip). Both cues would have to strike the cb at the exact same offset and cue speed. Test results should clearly show which one actually creates more cb spin (sideways rotation). Until that's done, it's all speculation.
My guess is that the hard tip would produce slightly more spin, as well as slightly more cb speed, because the soft tip will absorb more of the impact and transfer less energy to the cb.
Has anyone done such a test?
High speed video and actual REAL world says it doesn't. Have you tried PJ's experiment?? I have. I used a Ultraskin hard, a US medium and a house cue with a elkmaster. Shot 5-6 shots with each tip. Used a clean stripe ball and hit it in same place and with as close to same speed i could muster. ALL the shots came back to a spot less than the width of a chalk-cube apart. I then set up a draw shot about 3ft from the cb. Again, the ball came back to almost the same place each time. And this was using a Mezz and a house cue. Folks, the tip hardness has no effect in ACTUAL play. BTW, i don't think i'm anything on here but you and a couple others are as far out there as some of the CTE zealots. All i hear is "well, it has to be that way". Just because you think/feel it doesn't add up to squat.
The answer is there is no discernable difference. What difference there 'MIGHT' be is beyond miniscule and has no relevance to actually playing shots. The ball leaves far too fast. These guys keep quoting percentages but apparently they just don't realize how tiny these time differences are. An average eye-blink is about 150miliseconds. Cue-tip to cueball contact time is roughly 2-3miliseconds. Contact-time differences in the 10,000th/sec. range have no effect on how the cb reacts. My main point is if it doesn't effect playing the game why even worry about it? Crazy.
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I agree that it likely doesn't have much effect on playing the game. But experience tells me that whenever I switch from a hard tip to a soft tip I have to shoot certain shots with a little more effort. In other words, I'm with Lou Figueroa on this. There is definitely a noticeable difference (for me) between tips when playing delicate soft-speed shots with a lot of spin.
Probably a feel/sense thing more than any actual spin difference. That can be big in your head during a match. CB will come off slower and that can be useful in 1p too. I had to borrow a cue the other day and it had a Ultraskin Pro soft(reallllly soft) tip on it. Yes, the hit felt different but i didn't notice any spin difference. I did remember how much i hate soft tips tho. Felt like a wad of gum.
The percentage matters, or would in many things. How can you say that .001 second matters and .002 doesn't? In math and in many real world things it does double the effect. In pool time of contact is just one of a handful of variables. We don't have hard numbers for all of these variables so we guess or totally ignore them.
How efficient is the interface between tip and cue ball? If it is typically 50% efficient we could see huge gains or losses with changes and that extra .001 might be huge. However, if it is highly efficient, over 90%, nothing we can do will show a huge gain and we may not see a significant loss with a change.
I ran the test lab among other duties at a little R&D company. Every time the results on paper were different than those in the test lab the error was on paper. In fact, the error was the same thing we struggle with in these discussions, undefined variables. Sometimes there were enough undefined variables it was simply more practical to test than to try to run down all the variables. I genuinely had a blast running the test lab!
Just because of the empirical results from our limited testing and the results of play on the table I suspect the contact interface between tip and cue ball to be surprisingly good until we get out to the outer edges before a miscue. If a soft tip gives 90% and a hard tip gives 92% or vice-versa it just isn't going to matter for any practical purpose.
I like soft tips. I like a soft contact and over fifty years ago I formed the opinion that hard tips were more likely to miscue. I find miscues to be a nonissue with any tip now but I am happy with Elkmasters and after a brief flirtation with layered tips have found no reason to change.
Hu
CB being on the tip for a couple 10,000th's longer will have zero effect on the spin you get while actually playing the game.
WobblyStroke
Well-known member
Efren played Elk Masters pretty much his whole career. I think the one he had in a relatively recent 'whats in the bag' was a medium tho.
The one's he used when i saw him were milk-dud elks.
So, you don't buy the "same lever arm" argument? If not, what is the relationship of spin/speed ratio for different tip hardnesses in your theory? Is the change in spin/speed ratio directly proportional to the amount of tip compression?