Cue Tip Contact Myth-Busting Truths in Super Slow Motion

I will say this though. I have favored soft tips for years because I inherently have less of a fear of miscuing. However, I have set multiple shots up with different hardness tips and even shafts, regular, ld, cf and always get the same amount of spin per as consistent stroke that I can produce. I just like the feel of a soft tip better. I can "feel" the cue ball better and I am a position play fanatic. Perhaps I should concentrate more on not missing :unsure::unsure:
 
What camera equipment did you use dr Dave? What can a modern iPhone do? I saw some of the footage was the Russian cuemaker.

My last day job we had an in-house crash sled to test infant car seat collisions. I think it was 100,000 frames per second, and had lights around it as bright as a baseball stadium. I wasn't on the carseat RD team, so only saw it in use once in a while.
 
Oh, I do believe there is one tangible difference on a longer vs shorter contact time: The amount of abuse imparted onto the cue stick. The longer contact time would be less likely to crack a ferrule or shaft. Thus, maybe on shafts/ferrules known to split, such as Meucci and Predators, the move would be to use a soft tip.
 
FunChamp said:
Perhaps it's just me, but I generally don't tell someone with a PhD in physics that he is wrong about physics when I barely made it through Algebra 2 in high school. I find it comical that I see folks arguing traditional pool assumptions with a dude that has a PhD in physics and does experiments. The biggest experiment I ever pulled off was trying to tell my wife "no" on getting a second Margarita. It didn't end well.
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BOTH SIDES THOUGH!!!

QrGaCd3.jpeg
 
Interesting video.
Not surprised a softer tip has a larger contact area on the cueball at the maximum point of contact.
This is why they feel more 'grippy' to players.

I see someone already suggested chalk types.
That video would be fun to see Taom in action.

An additional video that would be interesting would be different ferrule materials, lengths etc.
That also makes a difference on some shots.
I have seen this recently with a Snooker cue, changed from brass to titanium and the deflection difference was huge.

Cheers Dave, always enjoy your threads.
 
If anyone wanted to set up a player to shoot a much softer tip vs a hard tip it could be fun to watch.

A myth busting video can provide conditions worth watching.

If a cue sales staff member wanted to sell harder tips as better because softer tips have more contact time would that be DrDave approved?
 
Patrick Johnson said:
What's the evidence they can do that?

One possible way is to hit lower on the CB so the speed wears off but the side spin doesn't - but that's not "the same speed".

pj
chgo
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Ye true, without measurable data we can't be sure. Could just seem that way I guess. The shot in question wasn't a draw by the way, it was a max inside 4 railer, but it def seemed like the ball was going in the same but the CB ran around a lot more using the technique Corey shared.
 
Hits 'em Hard said:
This is where you’ve created a problem. You’re using a set speed for your testing. It needs to be a variable speed. You need a slow/medium/fast strike on the cue ball with each hardness. That way there’s a full table of data to interpret. The math behind all of this says that a soft tip should be able to impart a higher rate of spin for the distance the cue ball travels. For simplicity’s sake, let’s say all tips top out at 2000rpm capable. The soft tip should impart a traveling speed that is less than that of a hard tip. Meaning the soft tip will spin more for the same distance traveled. That’s where the contact time plays a difference. Over 4 feet, let’s say the soft tip at maximum spin, takes 3 seconds to travel. That would imply that the cue ball spins a 100 times in that distance. Now using your data, the hard tip has 33% less contact time. That should mean it travels the same distance in 33% less time, so 2 seconds. So the cue ball effectively in the same distance has spun on 60 times.
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I did test at both slow (lag) speed and very fast (almost 4 table lengths) speeds to cover the extremes.

Concerning more explanations and proof backing up the various claims made, see the resources here:
cue tip hardness effects
and:
cue tip efficiency
 
Patrick Johnson said:
It's easy to test...

1. Use a marked ball (like the striped ball shown below, with the stripe vertical) so you can check chalk marks to be sure you're hitting at the same horizontal distance from center.
2. Shoot straight across table (like from the spot to the second diamond on the side rail) at just the right speed to rebound back to the near rail (or any repeat distance).
3. Mark the spot on the near rail that the ball hits.

In my experience, hitting the identical contact point and speed with different tips returns the ball to the same spot on the near rail - in other words, they both produce the same amount of spin.

pj
chgo

View attachment 687918
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Several examples of how to do this can be found in the videos here:
stroke swoop/swipe resource page
and more examples can be found here:
do LD shafts get more spin on the ball?
 
Cornerman said:
I think the major problem with the explanation using acceleration is that 99.999% of professional players don’t actually know what acceleration is. And without measurements, they don’t actually know if they’re accelerating.

The measured values any time these experiments have been done by any great stroking players, the acceleration right at the moment before impact is always nearly zero. What seems obvious to me is that professionals can efficiently and repeatable accelerate their cuestick to a velocity. It’s the velocity, not the acceleration that matters at impact along with the tip offset.
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This is true of most players (except those who tend to decelerate [slow down] into the ball, resulting in terrible speed-control consistency). Here are some examples:

 
iusedtoberich said:
Nice video, I enjoyed all the slow mo and the production value.

I did have the same initial reaction as Hit's em Hard. Dr Dave (and everyone forever), say (paraphrasing): "because the contact time is so small, extending it slightly for softer tips does not make a difference to anything". That never seems to be qualified with anything.

That said, I'm in agreement, that there are not tangible playability differences. The "proof" of that IMO, is every pro under the sun can make every shot under the sun. While one pro will use a 13.5mm shaft with an ivory ferrule and an elk master tip made in 1960, and another pro will use the latest CF shaft and Moori tip.
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FYI, supporting explanations can be found here:

 
FunChamp said:
Perhaps it's just me, but I generally don't tell someone with a PhD in physics that he is wrong about physics when I barely made it through Algebra 2 in high school. I find it comical that I see folks arguing traditional pool assumptions with a dude that has a PhD in physics and does experiments. The biggest experiment I ever pulled off was trying to tell my wife "no" on getting a second Margarita. It didn't end well.
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Well, here's the thing: the video said a hard tip stays in contact with the CB for 1.3 thousandths of a second, while a soft tip stays in contact with the CB for 1.9 thousandths of a second, so 6 ten thousandths of a second longer. Because 6 ten thousandths of a second is so short, it can't possibly affect anything, right? Well, wait a minute...6 ten thousandths of a second is 46% longer contact for a soft tip than a hard tip. Why can't nearly 50% more contact time create more spin? See how that works? When you look at percentages, the longer contact time for a soft tip seems like a lot more, doesn't it?
 
FunChamp said:
Perhaps it's just me, but I generally don't tell someone with a PhD in physics that he is wrong about physics when I barely made it through Algebra 2 in high school. I find it comical that I see folks arguing traditional pool assumptions with a dude that has a PhD in physics and does experiments. The biggest experiment I ever pulled off was trying to tell my wife "no" on getting a second Margarita. It didn't end well.
Click to expand...

Just for the record, my PhD is in Mechanical Engineering, not Physics. But most of the stuff I worked on and taught for 30 years was "physics."
 
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