Practical demonstration of cue tip path with a Pendulum stroke.

gregcantrall said:
I hope this is useful.:grin:
Click to expand...

More than useful to me. I was thinking of doing the same sort of thing, but you saved me a bunch of time. :wink:

Your little device is a very elegant proof of what we all know (almost all of us anyway). A perfect pendulum stroke delivers a straight cue right up to the contact point with the CB. After that, the natural motion of the arm raises the butt of the cue, causing the tip to drop to the cloth due to gravity... provided that you have a cradle grip that suspends the cue from the thumb and first or second finger somewhere behind the balance point of the cue. This tip action during the follow through can easily be seen just by stroking the cue to its natural finish without a CB in front of it.

I added a bright green line in Photoshop using the "line tool". How much straighter could you possibly get your stroke" Arcs? Malarkey! That stroke line is about a pencil line width away from the computer-drawn line at its maximum, with a sweet spot a measured 5" long. I propose to English! that he make a similar device, but with an articulated shoulder section added to it. Maybe he can show us all just how easy it is to refine that "huge" arc into a dead-straight line using two moving joints instead of one. Lol
 

Attachments

  • Stroke Line %22Sweet Spot%22 = 5%22.jpg
    Stroke Line %22Sweet Spot%22 = 5%22.jpg
    56.8 KB · Views: 503
Last edited:
ENGLISH! said:
Mr. Cantrell,

If you have the time & would be so kind, could you measure& relay how much the 'cue' butt raises in your model?

In Neil's video, his butt end raised up about 3 inches from my estimation. Maybe not at his hand as that is hard to see. I would guesstimate that his hand raised maybe near 2 inches.

Thanks if you choose to indulge me.

Rick
Click to expand...

Why the diversion, Rick? Of course the butt raises at the rear of the stroke. How could it possibly do anything else unless one was to open their fingers and let the cue drop to the fingertips? You got busted, admit it.
 
sfleinen said:
Greg:

Well done! As the readership can easily see, even with a perfectly-joined-pivot (where the arm/hand joins the cue), one can see just how *far* the straight travel of the cue is. The dive after contact with the cue ball is expected, and anyone who's been to SPF school knows this is taught. The dive to the cloth is old hat. In fact, you really have to BREAK the alignment -- really put effort into it -- to get the rise and fall that ENGLISH is brain-spinlocked on.

While this effort is for nothing on the ENGLISH front (you saw his classic twisting, diverting, "let me bury you with 50 unrelated questions to keep you mired in administrivia" response), this is great demonstrative info for anyone on the sidelines truly interested in *why* a pendulum stroke doesn't act the way you think.

Again, well done,
-Sean
Click to expand...

The results were unexpected to me as well. I have read most of the BS going on during this "debate" trying to see if it might yield a nugget or three to hang on to. Well it has now! Mr. Cantrall, I like the way you work!

For me I doubted the length of time that the tip would travel straight but to be honest after trying to play with a "static" elbow I didn't care. It is a more consistent way to stroke. That's all that matters anyways if the goal is to help people play better.

I will never say there is only one right way but a static elbow makes it easier to deliver the tip consistently. If I hit a shot where power is the goal my elbow will be moving just as it always has. But on today's fast cloth a true power stroke is not needed very often at all.

My $.02

Ken
 
I've only followed this discussion peripherally (there have been incarnations previous to this thread), but I'd like to make the comment that, to me, straight line travel of the cue tip is irrelevant. I only care about where the cue tip strikes the cue ball (assuming the tip is always moving within the same vertical plane).

That the tip may or may not travel in a straight line before contact, or dive to the table after contact, is inconsequential to what happens to the cue ball at contact.
 
Last edited:
Neil said:
Why the diversion, Rick? Of course the butt raises at the rear of the stroke. How could it possibly do anything else unless one was to open their fingers and let the cue drop to the fingertips? You got busted, admit it.
Click to expand...

Mr. Cantrell's model while not perfectly representative has fostered more food for thought than you video.

I was going to ask you if you would be inclined to have a civil dialogue.

But then I realized how you characterized my request to Mr. Cantrell as a 'diversion' & how you twisted measuring the distance of rise into making me appear to not know that it DOES RISE.

So, no dialogue with you. I think I may take the advice of those that wish me well.
 
Last edited:
Glad you could take it a step further

Sloppy Pockets said:
More than useful to me. I was thinking of doing the same sort of thing, but you saved me a bunch of time. :wink:

Your little device is a very elegant proof of what we all know (almost all of us anyway). A perfect pendulum stroke delivers a straight cue right up to the contact point with the CB. After that, the natural motion of the arm raises the butt of the cue, causing the tip to drop to the cloth due to gravity... provided that you have a cradle grip that suspends the cue from the thumb and first or second finger somewhere behind the balance point of the cue. This tip action during the follow through can easily be seen just by stroking the cue to its natural finish without a CB in front of it.

I added a bright green line in Photoshop using the "line tool". How much straighter could you possibly get your stroke" Arcs? Malarkey! That stroke line is about a pencil line width away from the computer-drawn line at its maximum, with a sweet spot a measured 5" long. I propose to English! that he make a similar device, but with an articulated shoulder section added to it. Maybe he can show us all just how easy it is to refine that "huge" arc into a dead-straight line using two moving joints instead of one. Lol
Click to expand...

The lack of variation from straight was what surprised me. Using my layman's mechanical engineering knowledge I predicted that a variation of 3/16" at the stroke hand would become a 1/32" variation at the cue tip. I did not factor in the change in the length of the lever arms when the cue is drawn back with the tip close to the bridge. Your straight line over the pencil line shows it is far less. The same change in the length of the lever arms is what accounts for the tip going to the cloth more quickly after contact with the ball.

I am glad you added the green line. I welcome anything else you can build upon my simple little demonstration.:thumbup:
 
Personally I only care if I pocket the ball & put the CB where I want it.

That means that I care what the tip does to the cue ball. If the tip contacted the cue ball & stopped immediately, what would be the result? IMO it is what the tip does from contact with the ball until the ball leaves the tip that is important. That is, 'during' contact.

It appears to me that Mr. Jewett has studied & tracked the tip path for the fixed elbow stroke to move along 3 arcs & he has studied & tracked the path for an elbow drop stroke to be straight. They are different.

RandyG asserted that the tip moves 'level'/straight for several inches in what he termed a 'sweet spot' for a fixed pendulum stroke.

Those certainly seem to be in conflict to me.

I would think that a clarification of some kind would be in order.
 
Last edited:
ENGLISH! said:
My Cantrell's model while not perfectly representative has fostered more food for thought than you video.

I was going to ask you if you would be inclined to have a civil dialogue.

But then I realized how you characterized my request to Mr. Cantrell as a 'diversion' & how you twisted measuring the distance of rise into making me appear to not know that it DOES RISE.

So, no dialogue with you. I think I may take the advice of those that wish me well.
Click to expand...

Rick, I am not interested in a civil discussion with you until you make your much needed apologies to Greg, Tony, Sean, Randy, Scott, Jon, myself, and anyone else you have debased in regards to this subject. You have been proven wrong so convincingly, that your denial of it has made people think that you are actually mentally handicapped and not just too prideful to admit you were wrong all along.

In this thread, you refuse to see a straight line as a straight line. In the other thread, you refuse to view the video as you were asked to a number of times, and say it shows nothing. You have lost all credibility on here because of your pride and vindictiveness. Even those tying to give you the benefit of the doubt, have said you are wrong. When will this all end??
 
I think sometimes people's pride gets the best of them. They do not want to admit they are wrong as in their head it shows weakness in their input to the forum (regardless if they are wrong or not). We all make mistakes and need to man up to them when they occur. It doesn't make the input less valuable moving forward and actually shows good character by admitting the mistake and moving on.
 
Exactly!

swest said:
I've only followed this discussion peripherally (there have been incarnations previous to this thread), but I'd like to make the comment that, to me, straight line travel of the cue tip is irrelevant. I only care about where the cue tip strikes the cue ball (assuming the tip is always moving within the same vertical plane).

That the tip may or may not travel in a straight line before contact, or dive to the table after contact, is inconsequential to what happens to the cue ball at contact.
Click to expand...
Yep, I want a consistent repeatable stroke. Makes no never mind to me if it is and arc, straight line or cork screw. Just want to be able to hit the cue ball where I want and do it the same every time.
 
Bob Jewett said:
Interesting. How does the plot change when the grip is moved up on the butt? How about back? Is there any grip position that gives a visibly concave-up curve? (Easy for me to ask from the comfort of my computer chair.)
Click to expand...

I think you would have to be lying on the floor while shooting to achieve that:grin:
 
gregcantrall said:
Yep, I want a consistent repeatable stroke. Makes no never mind to me if it is and arc, straight line or cork screw. Just want to be able to hit the cue ball where I want and do it the same every time.
Click to expand...
Some people have forgotten what matters.

If my stroke had a severe downfall, say I line up center but every time I try I hit 2cm to the right of centre, you can adjust your starting position.

...well you could, but you might want to see an instructor first. Come to think of it you might as well sign your soul over to the devil too!! :)
 
ENGLISH! said:
Thanks for the chuckle. But...

that is not what I had in mind.
Click to expand...
I was only jesting :)

But it turns out I don't need to show you the straight line, another poster posted Gregs picture with a green computerised line against the pencil line. If you can't see atleast 1" of straight line in that then there is no more that can be done for now.

You may not see it as backing up RandyGs statement, but you have to understand others, including my self do.

I'm sure in a few days or so we will have a new thread to bicker and squabble over ;)
 
ENGLISH! said:
That means that I care what the tip does to the cue ball. If the tip contacted the cue ball & stopped immediately, what would be the result? IMO it is what the tip does from contact with the ball until the ball leaves the tip that is important. That is, 'during' contact.
Click to expand...

The distance travelled by the cue during contact is about 4mm according to this excellent video: http://www.youtube.com/watch?v=rhNgiAwQ1jo (from DBK's blog here: http://dbkcues.ru/2011/06/12/another-couple-of-hs-video-now-24-000-fps/?lang=en)

Here is a still from the video exactly at first tip-CB contact (note 37.7 cm at left edge of frame)

8EENXIX.png


and then again once cue ball is away (note 38.1 cm at left edge of frame)

K0QeII7.png


Here, I've overlayed what the 4mm contact distance looks like, relative to Greg's experiment result:

Mo7qouM.png


English, are you really concerned that the cue path is not "perfectly" straight during that 4mm distance, or is this just an elaborate long-form troll?
 
And....

even if the stroke during that 4mm isn't 'exactly' straight, but remains in a vertical plane, then I say there is no meaningful consequence to the outcome of the shot.

.
.

It's ok. Just say, "Yeah, I see what you mean." It's not so hard.
 
Spimp13 said:
I think sometimes people's pride gets the best of them. They do not want to admit they are wrong as in their head it shows weakness in their input to the forum (regardless if they are wrong or not). We all make mistakes and need to man up to them when they occur. It doesn't make the input less valuable moving forward and actually shows good character by admitting the mistake and moving on.
Click to expand...

It's not always pride. The term "confirmation bias" covers most of the disagreements we see here and in all avenues of life. To let go of deep-seated convictions is often an impossibility because accepting new facts that prove our previous thinking to be false is an insurmountable mental obstacle to leap for most folks. If we are so easily proven wrong here, what about our other deeply-held convictions? Is it possible we may be wrong about everything? This notion is just too foreign to accept, especially for thoughtful types who are confident in their reasoning power... like almost every poster on this forum.

Even esteemed scientists fall prey to it, often more than laypersons do. Perhaps the greatest mind in 20th century chemistry was Linus Pauling, who proposed, had published, and actually defended a 3-stranded model of DNA that he had come up with, even though the chemistry that proved it to be an impossible structure was discovered by Pauling himself years before that. Had he seen Rosalind Franklin's x-ray crystallography work on DNA ahead of publishing his paper (as Watson and Crick had), he would have never believed he had the correct structure. Likewise, if Mr. English had a glimpse of Mr. Cantrall's stroke plots he most likely would never gotten himself in the pickle he's in now.

Rick, I'd strongly suggest that you look at the evidence brought forth here (both Neil's video and Greg's device) with a fresh mind. The proof is there, and you can run, but you can't hide. Not from this crew at any rate. Admitting you were wrong will feel like a cool autumn breeze, allowing you to escape the weight of your defense of an untenable idea. It will also bring you much further into the good graces of those members whom you have insulted repeatedly in your desperate attempts to reconcile your erroneous logic with the facts which are so obviously contradictory to it.
 
You must log in or register to reply here.
Back
Top