Why can't I tranfer spin on this shot?

Patrick Johnson said:
...You should be able to transfer enough spin through an OB to a second OB to get some throw and some sidespin on the second OB - enough to bank it in the corner.
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UPDATE: I tried this shot last night with new clean balls and was surprised how little action I got on the 2nd OB. It came nearly straight back off the rail, nowhere near the corner pocket. Guess I overestimated how much spin can be transferred through an intervening ball.

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However, with the same new clean balls, I could easily throw one OB into the corner pocket (or even past it) and stop the CB dead (with no drifting to the right).

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pj
chgo
 
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Patrick Johnson said:
Here's a better setup.

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You should be able to transfer enough spin through an OB to a second OB to get some throw and some sidespin on the second OB - enough to bank it in the corner. Don't overpower the shot, use only about 1/2 maximum sidespin and be sure to hit a stop shot.

pj
chgo
Click to expand...


I haven't tried this shot but I would imagine that the two ball will not bank unless you hit the one ball a little bit to the right of it's center. Using the left side spin, the cue ball may squirt enough to hit the one ball off center.

I doubt if you hit the one ball DEAD CENTER, that it will impart enough side spin to the one and then the two ball so that the 2 can be banked in the pocket.

But I'll try it.......

JoeyA
 
Danny Kuykendal said:
Joey, great video, shows it exactly as it is. What more proof do you need?
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Danny, I'm not sure which video you are talking about and I'm not sure if you know which shot I'm talking about. Just to be sure:

I'm talking about the one and the two ball frozen to each other and you hit the cue ball into the one ball with left side spin, hoping to impart enough right side spin on the one ball and enough left side spin on the two ball to bank it in the hole (as depicted in Pat's cuetable diagram).

I posted before I read Pat's test that he did last night which is what I expected.

If you have a video with the two balls frozen and the two still banks, I have to think that there is some other force at work (extra friction) but I could be wrong.


Still, send me the link to the video you are talking about. Thanks,


JoeyA
 
throw travesty

Cornerman said:
I think this shot has been lied about for decades, and even today people will still tell you that you can throw by spin alone some unbelievable amount. People base their entire teaching of english on this. Others write books about it. Others will never try it on a table, but put the shot up on the Wei table like it's gospel. That's a travesty.
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Understood. Fair enough.

Dave
 
Bob,

FYI, TP A.29 supports your statements. Also, the second half of my July '07 article provides some illustrations and further discussion. In the article, I mention your July '03 article, where you first presented the excellent experiment for people to try.

Regards,
Dave

Bob Jewett said:
Fred is also right about some authors exaggerating the usefulness of "cutting a ball in with throw." This is the technique of keeping the cue ball from moving to the side on a nearly straight-in shot by hitting the shot straight and using side spin to throw the ball in the pocket. This is sort of the shot that you are looking at.

View attachment 74658

The goal is to make both the cue ball and the object ball move towards the rail to the left. Or, you can try to make the cue ball end exactly a ball from the cushion -- just like it starts -- and cut the object ball to the left to the far corner pocket. The question is whether this is possible, and if it is, how far apart can the two balls be and still get them to both go to the left (or have the OB move to the left and not have the cue ball move to the right.
Hint: at some separation, it is possible to make the object ball in the far pocket and make the cue ball hit the cushion to the left. (And without a cheat such as masse -- it can be done with a level stick.)

The "GB" is there to let you know if the OB has moved to the left. Remove it if you are trying to pocket the the OB.
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"hold" shot resources

Colin,

FYI, the full explanation (with illustrations) can be found in my July '07 article and TP A.29.

Regards,
Dave

Colin Colenso said:
Bob,
That's an interesting challenge.

I'd expect the throw force leftward on the OB is the same and opposite to the throw force rightward on the CB.

But as the OB is moving against the cloth already, the relative friction opposing the leftward movement is less than the friction exerted on the CB. Hence the OB travels further to the left than the CB does to the right.

Could there be another explanation?

Colin
Click to expand...
 
Yea, Joey, it was the video you put up where the balls were separated. I will experiment with the shot today.

I guess you have a problem with throw and english. In other words, throwing the ball to the right and at the same trying to impart left hand spin onto the object ball with right hand spin on the cue ball, and banking it to the left.
 
Colin Colenso said:
... But as the OB is moving against the cloth already, the relative friction opposing the leftward movement is less than the friction exerted on the CB. Hence the OB travels further to the left than the CB does to the right. ...
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I don't fully understand what your point is, but here are two things to think about that may be related:

I think that cloth friction is entirely irrelevant in meeting the challenge posed in my diagram. If both balls are moving partly to the left immediately after the collision, nothing about the cloth will instantaneously stop them or cause them to move to the right.

Also, as far as anyone can tell, the surface the balls are on has essentially no influence on what happens during the ball-ball collision. Sometimes the effects of the cloth before and after the collision makes it appear otherwise, but the contact time (around 0.2 milliseconds) is too short for ball-cloth friction to have any noticeable effect during the collision.
 
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Patrick Johnson said:
However, with the same new clean balls, I could easily throw one OB into the corner pocket (or even past it) and stop the CB dead (with no drifting to the right).
Click to expand...
I'd have to see it to believe it. In Dr. Dave A.21 video, you can see that he spins the bankit in, no problem with nary a drift of the cueball. But, he doesn't throw it past that diamond like you're suggesting in your layout. His ball goes about as straight as I'd expect given all of the videos he's made of similar shots.

Maybe you meant "spin in it," so I'm objecting about the words "throw one OB in the corner" with your arrow pointing to the left of the diamond.

It might seem like nitpicking, but that's exactly what the question was about to begin with (the arrow to the first cushion).

Fred
 
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Cornerman said:
I doubt it. Or, I have to see it to believe it. In Dr. Dave A.21 video, you can see that he spins it in, no problem with nary a drift of the cueball. But, he doesn't throw it past that diamond like you're suggesting in your layout. His ball goes about as straight as I'd expect given all of the videos he's made of similar shots.

Maybe you meant "spin in it," so I'm objecting about the words "throw one OB in the corner" with your arrow pointing to the left of the diamond.

It might seem like nitpicking, but that's exactly what the question was about to begin with (the arrow to the first cushion).

Fred
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You're right - I wasn't careful about showing the throw/spin effects realistically because I didn't realize that was the focus of the thread. I practice throwing object balls and know about how much to expect. It's not as much as I drew in the diagram, but it's a clearly visible amount. I'll measure it tonight and report back.

pj
chgo
 
Patrick Johnson said:
You're right - I wasn't careful about showing the throw/spin effects realistically because I didn't realize that was the focus of the thread. I practice throwing object balls and know about how much to expect. It's not as much as I drew in the diagram, but it's a clearly visible amount. I'll measure it tonight and report back.

pj
chgo
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A little less than a ball's width (about half what shows in my diagram). I used bluepepper's setup (with the blocking ball to prevent cutting).

pj
chgo
 
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Danny Kuykendal said:
Yea, Joey, it was the video you put up where the balls were separated. I will experiment with the shot today.

I guess you have a problem with throw and english. In other words, throwing the ball to the right and at the same trying to impart left hand spin onto the object ball with right hand spin on the cue ball, and banking it to the left.
Click to expand...

Danny show me the video that I put up of the following shot:
I'm talking about the one and the two ball frozen to each other and you hit the cue ball into the one ball with left side spin, hoping to impart enough right side spin on the one ball and enough left side spin on the two ball to bank it in the hole (as depicted in Pat's cuetable diagram).

I must be missing something......

Thanks,
JoeyA
 
Bob Jewett said:
I don't fully understand what your point is, but here are two things to think about that may be related:

I think that cloth friction if entirely irrelevant in meeting the challenge posed in my diagram. If both balls are moving partly to the left immediately after the collision, nothing about the cloth will instantaneously stop them or cause them to move to the right.

Also, as far as anyone can tell, the surface the balls are on has essentially no influence on what happens during the ball-ball collision. Sometimes the effects of the cloth before and after the collision makes it appear otherwise, but the contact time (around 0.2 milliseconds) is too short for ball-cloth friction to have any noticeable effect during the collision.
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Oh, you're right, I was perceiving the force as something like a spinning ball acting on the surface over time, rather than pretty much an instantaneous force during collision.

Colin

ps: Bob,
Is the solution to your challenge reliant mostly on CIT?

Seems to me if I place the balls about 1 inch apart I could shoot slightly left of center on the OB and the CIT alone would throw it toward the left corner? A touch of right english may make the shot easier.
 
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Cornerman said:
That looks like it's in line with Dr. Dave's other video where he has the paper next to it for reference ( http://billiards.colostate.edu/normal_videos/new/NVB-21.htm ).

Fred
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But... with the blocking ball I could bank it into the pocket consistently, but not past it. So the times I got it past the pocket before (without the blocking ball) I must have been cutting it a little.

Just goes to show you need controls to know what's really happening - I should practice more consistently what I so often preach.

pj
chgo
 
dr_dave said:
Colin,

FYI, the full explanation (with illustrations) can be found in my July '07 article and TP A.29.

Regards,
Dave
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Dave,

Could I express that in layman terms this way?

By thickening the cut angle, there is a significant reduction in the tangential deflection speed of the CB. This reduction is greater than the throw component which adds some speed in the same direction.

e.g. Thickening the cut reduces CB tangential deflection speed by 0.2 m/s. The english required to do this adds perhaps 0.15 m/s of throw. A net reduction of 0.05 m/s.

Colin
 
Colin Colenso said:
... Is the solution to your challenge reliant mostly on CIT?

Seems to me if I place the balls about 1 inch apart I could shoot slightly left of center on the OB and the CIT alone would throw it toward the left corner? A touch of right english may make the shot easier.
Click to expand...
If the balls are very close, CIT is the thing to use. But as the balls get farther apart, I think you will find that right side spin is necessary. The real question in the shot is how to shoot to make the object ball come over one ball in five+ diamonds while leaving the cue ball on that same line with the balls farther apart.This tests the theory that you can "kill" the cue ball with outside english on nearly straight shots.
 
Ohhhhh. I just realized that the shot Bob is describing doesn't actually have a blocking ball just left of the cueball. That hazy ball against the cushion was just to show the distance from the cushion. Now I can see how it can work. I was wondering how you could get past that ball in order to send the cueball to the left.
 
Bob Jewett said:
If the balls are very close, CIT is the thing to use. But as the balls get farther apart, I think you will find that right side spin is necessary. The real question in the shot is how to shoot to make the object ball come over one ball in five+ diamonds while leaving the cue ball on that same line with the balls farther apart.This tests the theory that you can "kill" the cue ball with outside english on nearly straight shots.
Click to expand...
I tried the CIT, have to be very close to the OB. Like within 1/8th inch. I guess that follows the same rule as plants that are a few mm apart can't be turned.

Using right english I could make the shot and get CB on rail with about 1 inch separation. I didn't see how far I could go to pocket the ball keeping the CB on the line. I'll have to try that next time.

Colin
 
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