Question about intentional swerve

The Renfro said:
Soft or super soft will extend the contact at slow speeds past 2ms and you will be able to torque the cueball crossing over... You think Efren plays a pressed elk because he can't afford a layered tip?
Click to expand...

Hi there.
I really like your informative posts.

What's that? 2 milliseconds? Impossible from what I've read here.

Did you see the "Canon vid"? Rubbing/swiping 3 balls time after time down the side of he rail with no travel? That doesn't come up much during practice or games.

I prefer a soft unpressed Elk Master without milk, slathered with deep penetrating chalk please. I have gotten lazy and don't like to trim the mushroom and tips that often. :wink:

Yes Efren also said to us that he uses a tight bridge and a loose grip...but how does he swipe when he starts the shot with the tip at the bottom of the CB? Does he lft the bridge or drop the cue butt or both?

Be well.
 
dr_dave said:
CJ,

I'm not sure who you mean by "we," but I'll assume you mean people who think a swoop stroke can do something to the CB that a straight stroke can't. Regardless, it doesn't really matter who "we" are anyway.

I agree with you that if one is getting a different result, then one is doing something differently, causing the CB to be hit in a different way (e.g., below center, at a different angle, with a different effective tip offset, etc.). But again, these differences can also be created with an equivalent straight stroke at an appropriate aim, tip contact point, and cue elevation. And for many (if not most) people, a straight stroke will be more accurate and consistent than a swoop/swipe stroke.

Regards,
Dave
Click to expand...

"We" meant "You and Me"........
 
LAMas said:
Hi there.
I really like your informative posts.

What's that? 2 milliseconds? Impossible from what I've read here.

Did you see the "Canon vid"? Rubbing/swiping 3 balls time after time down the side of he rail with no travel? That doesn't come up much during practice or games.

I prefer a soft unpressed Elk Master without milk, slathered with deep penetrating chalk please. I have gotten lazy and don't like to trim the mushroom and tips that often. :wink:

Yes Efren also said to us that he uses a tight bridge and a loose grip...but how does he swipe when he starts the shot with the tip at the bottom of the CB? Does he lft the bridge or drop the cue butt or both?

Be well.
Click to expand...

yeah yeah... I get that maybe about who's posts are informative... everytime they test anything it's like hitting a nail with a hammer... ;)

The ruskies actually did speed AND hardness...

phenolic vs moorim.jpg

x axis is speed and y is contact time..

.8 is phenolic and the other graph is the moori m

Amazingly I make tips and will bet on 3ms and longer contact periods on our SS or even Softs... which will change the force vectors........

Sarcasism detection is off so I may have to apologize btw...

Chris
 
dr_dave said:
CJ,

I'm not sure who you mean by "we," but I'll assume you mean people who think a swoop stroke can do something to the CB that a straight stroke can't. Regardless, it doesn't really matter who "we" are anyway.

I agree with you that if one is getting a different result, then one is doing something differently, causing the CB to be hit in a different way (e.g., below center, at a different angle, with a different effective tip offset, etc.). But again, these differences can also be created with an equivalent straight stroke at an appropriate aim, tip contact point, and cue elevation. And for many (if not most) people, a straight stroke will be more accurate and consistent than a swoop/swipe stroke.

Regards,
Dave
Click to expand...


CJ likes to employ the royal "we." He's been doing that since he got here.

Either that or he runs around with a gerbil in his pocket.

Lou Figueroa
 
The Renfro said:
Soft or super soft will extend the contact at slow speeds past 2ms and you will be able to torque the cueball crossing over... You think Efren plays a pressed elk because he can't afford a layered tip?
Click to expand...


Or maybe it's just what he's used to.

Lou Figueroa
 
The Renfro said:
Soft or super soft will extend the contact at slow speeds past 2ms and you will be able to torque the cueball crossing over... You think Efren plays a pressed elk because he can't afford a layered tip?
Click to expand...

Hi Chris,

I've played Elk Masters & Brunswick Blue Diamonds for 45 years (mostly Elks) before going to a Kamui SS because it came on the shaft.

It seems that many don't get that it's about the contact time & timing what happens during that time.

I'm glad to see some other like thinking individuals. I knew we had some other like thoughts.

Best 2 You & Yours,
Rick
 
The Renfro said:
yeah yeah... I get that maybe about who's posts are informative... everytime they test anything it's like hitting a nail with a hammer... ;)

The ruskies actually did speed AND hardness...

View attachment 376666

x axis is speed and y is contact time..

.8 is phenolic and the other graph is the moori m

Amazingly I make tips and will bet on 3ms and longer contact periods on our SS or even Softs... which will change the force vectors........

Sarcasism detection is off so I may have to apologize btw...

Chris
Click to expand...

Great chart Chris.

I wish that there was a high speed camera vs time...I saw one where the tip gets crushed and recovers at contact.

Vectors Victor.:wink:

I think that I will change my tip back to an Elk Master.

Be well.
 
The Renfro said:
Soft or super soft will extend the contact at slow speeds past 2ms and you will be able to torque the cueball crossing over... You think Efren plays a pressed elk because he can't afford a layered tip?
Click to expand...

I feel there has not been enough work done to examine exactly what happens during that "brief" contact time. People get all onboard when they hear, "the contact only lasts a thousandth of a second or two". An impulse that is twice as long will create twice the momentum, so it makes a huge deal exactly how long that impulse is.

And yes, I do understand that the impulse is an integral function, but that doesn't mean that an identical change in momentum is guaranteed between a soft tip and a hard one. As well. the force vector changes during a properly executed swoop stroke, as does the coefficient of friction, the apparent mass of the CB, and many other minor factors that are stroke dependent. Show me the experimental data on all this, not just the theory. Until then, I feel pretty sure that if I just throw the cue at the ball and hit it in the same place, angle, and speed as CJ Wiley, it ain't gonna act exactly the same, or even close.

I'd be really interested in looking at what you know about all this from your tip research, because I feel you have a deeper understanding of all this than some folks want to give you credit for.
 
Sloppy Pockets said:
An impulse that is twice as long will create twice the momentum
Click to expand...
Only if all else is equal, such as tip hardness and stroke speed. But changing those things are how contact time is changed, so they're not equal by definition.

I'm guessing it's an even trade or worse - slower stroke speed, for instance, apparently increases contact time, but we all know from experience that it decreases CB speed. So much for the contact time = momentum formula.

pj
chgo
 
Sloppy Pockets said:
An impulse that is twice as long will create twice the momentum, so it makes a huge deal exactly how long that impulse is.
Click to expand...
This is not true in relation to cue tip contact; because for a given stroke, if the contact time is longer, the force between the tip and ball will be less (and the resulting impulse will still be the same, for a given stroke).

Regards,
Dave
 
Patrick Johnson said:
Only if all else is equal, such as tip hardness and stroke speed. But changing those things are how contact time is changed, so they're not equal by definition.

I'm guessing it's an even trade or worse - slower stroke speed, for instance, apparently increases contact time, but we all know from experience that it decreases CB speed. So much for the contact time = momentum formula.

pj
chgo
Click to expand...

Yes, but slower stroke speed also carries less momentum in the cue, so your point is moot. I never said there was any sort of linear relationship between contact time and momentum all by itself. There has to be a force applied over that time. The theoretical assumption is that a harder tip produces a greater force on the CB over a shorter time, but a softer tip gets the same result by applying a lesser force over a longer time, so they are equal. I dispute that assumption. I want the facts.

There is no single formula or set of formulas that can accurately describe everything that is going on with a simple hit of the cue. What happens at that interface is an extremely complex interaction, with force vectors large and small all over the place. It is way beyond what most of us learned in HS physics class. If the jury was truly out on all this, guys like Rod Cross wouldn't be continuing to do research on it.
 
Sloppy Pockets said:
Yes, but slower stroke speed also carries less momentum in the cue, so your point is moot. I never said there was any sort of linear relationship between contact time and momentum all by itself. There has to be a force applied over that time. The theoretical assumption is that a harder tip produces a greater force on the CB over a shorter time, but a softer tip gets the same result by applying a lesser force over a longer time, so they are equal. I dispute that assumption. I want the facts.

There is no single formula or set of formulas that can accurately describe everything that is going on with a simple hit of the cue. What happens at that interface is an extremely complex interaction, with force vectors large and small all over the place. It is way beyond what most of us learned in HS physics class. If the jury was truly out on all this, guys like Rod Cross wouldn't be continuing to do research on it.
Click to expand...

Good post.

Do the force vectors change if the tip is also "Swiped" or moved laterally during the contact? Rhetorical?

Be well.
 
Sloppy Pockets said:
Yes, but slower stroke speed also carries less momentum in the cue, so your point is moot.
Click to expand...
That is my point - changing tip/CB contact time requires changing other things, like stroke speed, that counteract your intended effect.

What beneficial effect do you expect from changing contact dynamics? Do you have a hypothesis?

pj
chgo
 
Patrick Johnson said:
No prob. What's your idea about what might be changed during contact?

pj
chgo
Click to expand...

I'm not quite sure anything should be changed during contact. That's not my point. I just don't see the value in arguing either side until more detailed analysis has been done. The very idea that we now know everything about cue/ball or ball/ball interactions goes against all I've learned about research. There are always surprises in store when you look deeper. The best scientists I worked with never drew final conclusions, they just kept looking deeper.
 
And in the meantime (and this is not directed at you, Pat), the notion that players like Archer, Sigel, and Wiley are going to benefit in the least by a concerted effort to force them to recant on their thinking that many "know" to be incorrect is humorous at best. All it does is create hostility on this board and drive them away.

I only wish folks would stop trying to force feed them this information, or try to bait them with loaded questions and then ambush them when they give the "wrong" answer. It's just a bad way for grown men to act. I decided to turn away from this and treat these guys with the respect they deserve.

Pool is an art as much as it is a science. At their best, these champions paint masterpieces on the table, and we are lucky we live in times where these works of art can be recorded and enjoyed by all, for a very long time. I just wish there were more of them here.

Anyway, I'm outa here. Gotta go look at my new (free) DVD I just got in the mail from CJ. You gotta respect the man for doing stuff like that if nothing else.
 
Sloppy Pockets said:
Yes, but slower stroke speed also carries less momentum in the cue, so your point is moot. I never said there was any sort of linear relationship between contact time and momentum all by itself. There has to be a force applied over that time. The theoretical assumption is that a harder tip produces a greater force on the CB over a shorter time, but a softer tip gets the same result by applying a lesser force over a longer time, so they are equal. I dispute that assumption. I want the facts.

There is no single formula or set of formulas that can accurately describe everything that is going on with a simple hit of the cue. What happens at that interface is an extremely complex interaction, with force vectors large and small all over the place. It is way beyond what most of us learned in HS physics class. If the jury was truly out on all this, guys like Rod Cross wouldn't be continuing to do research on it.
Click to expand...

Good Post.

Yes, & some often leave out parameters as they discuss 1 or 2 other parameters & then make a definitive conclusion.

Sincere Best Wishes to You & Yours,
Rick
(Whether you believe me or not)
 
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