yrraltsafone
Banned
jsp said:
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If you have no clue, what center ball is, then how can I communicate with you.
effect bottom has on an object ball when cutting?
- Thread starter goingproin07
- Start date
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If you have no clue, what center ball is, then how can I communicate with you.
CaptiveBred said:
Well I'm glad to see I'm not the only who stroke seems to produce this effect too. I get the same thing - Lots of draw (Especially with a long stroke and a loose wrist) at any cut shot of more than a few degrees will induce the object ball to throw wide. Even very narrow shots can be thrown if I stroke it well enough. If I don't compensate for it I overcut the ball. It is of course possible that some flaw in my stroke causes me to inadavertently add in some unplanned side-spin when my intention is to only use straight bottom spin which is causing the throw. However as I get this effect if I cut the ball to either the left or right I get the same effect this seems doubtful to me.
The other factor that affects this seems to be the distance from the cue ball to the object ball, and a correlated effect of the speed of the hit. If the object ball is close to the cue ball I don't get nearly as much of this draw/throw effect. The speed is correlated because, like other shots, I can chose to shoot very slowly to ensure the cue ball is not sliding at impact if I need for positional reasons to take advantage of the draw/throw effect, or choose to shoot harder if I need to reduce or eliminate this effect.
EDIT - I forgot to mention to me it seems shots with follow do get narrowed by the inverse of this effect, but the degree of variance from the expected angle is less extreme than with my draw shots. Perhaps this is an indicator my follow stroke is not as strong as my draw.
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Well, for what it's worth, if you play Virtual Pool (2, I think) and turn on the aiming tool, it adjusts to cut more the higher you cue and to cut less the lower you cue (this is using center ball). I don't how much stock you can place in that, but I do seem to undercut extreme follow shots and frequently overcut draw shots.
CaptiveBred said:
Nice post captivebred....u really gave me the explanation i was looking for....i didnt really get the physics post that everyone was talking about, so i didnt say anything, but thanks for making it simple....now i know what i need to do to make the shot....thnx
Colin, as you know the amount of throw very much depends on shot speed. According to my figuring, a difference between a slow stun shot of say 4 or 5 mph, and a nearly full draw or follow one at this speed or brisker, can mean as much as 2 - 2.5 degrees of difference in the throw at this cut angle, which I take to be about 30 degrees (half-ball). That means around an inch difference in the sideways travel over the 2' the object ball has to cover in this particular case.Colin Colenso said:
Comparing full draw or follow against stun with both shots at 8-10 mph yields a difference of only about one degree of throw, or a little less than a half-inch at the pocket.
So in either case, if you're hitting center pocket with stun, throw differences by themselves shouldn't cause a miss here.
Jim
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Dude, there is NO change for pure follow or pure draw....You would have to be swiping or pulling either to the left or right as you go through the cue in order to miss here. Many people do it. As you stroke through the ball there is a tendency when drawing to snap the wrist, it actually helps with the draw, but if you snap the wrist to the inside or outside at all you're not going to hit the ball squarely on the vertically center plane and you will cause squirt....
No, I'm saying that the total friction (rubbing across the surface of the object ball) is the same. The problem when you use both follow (or draw) and side spin is that you can't rub both ways (up and across, say, if you draw) with the same effectiveness as if you just rub in one direction (just sideways) as far as the throw is concerned.JoeyA said:
Suppose you have something like a double spot shot at one pocket, and you're trying to make the back ball into your pocket, and it's almost straight in. You know this shot is normally impossible, but suppose it is spotted a little off so the back ball can nearly be made in your pocket. What spin are you going to use to throw it in? For maximum grab, I'm betting that you will automatically use low speed and something like a stop shot. I'm also betting you will hit it fairly softly. Am I right?
Have you ever tested this, or is it just the feeling you have about how you aim with follow and draw?Jaden said:
8ball said:
My testing says otherwise...
What about CIT (collision induced throw)? its real and independent from spin...
very interesting post. It will be hard for someone to actually prove it, but im a believer too, that draw or folow has an influence, and i believe the answer is in the contact trow.
my experience= ob= center of table, cb =at corner pocket
draw : ob hits long rail first
folow: ob hits short rail first.
i dont know 1/10th of the physics u know, but i do know its not from my stroke; and simple reasoning behind it is. If i have a added left englisch from my bad stroke, wrist movement or whatsoever. then if i put OB on center of table, CB at headspot if i pot the ob left corner, or right corner, my ob would have to squirt in the same direction (opposite of my left englisch), but my ob moves to the right when trying to pot in the rightcorner with draw, and it moves to the left when trying to pot in the leftcorner with draw...
now i hope my bad englisch made any sence.
my experience= ob= center of table, cb =at corner pocket
draw : ob hits long rail first
folow: ob hits short rail first.
i dont know 1/10th of the physics u know, but i do know its not from my stroke; and simple reasoning behind it is. If i have a added left englisch from my bad stroke, wrist movement or whatsoever. then if i put OB on center of table, CB at headspot if i pot the ob left corner, or right corner, my ob would have to squirt in the same direction (opposite of my left englisch), but my ob moves to the right when trying to pot in the rightcorner with draw, and it moves to the left when trying to pot in the leftcorner with draw...
now i hope my bad englisch made any sence.
I'm afraid I feel another graph coming on. The short answer is that this appears to be true: the added cut angle overwhelms the masse action after a certain cut angle is reached, and the masse effect is not very big to begin with at small elevations. The plot is a little artificial in that it uses a constant throw value to arrive at the imparted spin.Bob Jewett said:
I'm drawing from Cushioncrawler's ideas here. He thinks that the spin axis will reach an equilibrium position such that it's tilted backward or forward away from the perpendicular (depending on whether it's right or left spin). Presumably, the amount of tilt would be equal to the effective slope of the cloth and curving would end when equilibrium is reached. I don't see any reason to doubt this, do you?Bob Jewett said:
He thinks that the ball will curve the other way as it comes to a stop, which I also agree with. All of us have probably observed this numerous times, if it's true, but I can't myself recall any specific instance. I would think though that as the ball slows down, the cloth slope would increase ever so slightly causing it to curve in the original direction before finally settling in? If true, maybe absolute equilibrium is never really achieved. But of course we're talking about very small effects.
I suspect you've looked at these things yourself. If so, and if you find the above unrealistic, please fire away.
Jim
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question, corroberation and banks
so, i read the post and was still a bit unclear on one point. does follow or draw cut the ball more?
to back up what people have said, a rolling ball has always cut the ball a little more, i have to aim a bit fuller. for me, when i draw the ball and there is a substancial angle, i almost always apply at least a quarter tip or so of outside... so, i'm not that familiar with what a center ball draw stroke will do on a cut, but as people have stated, i guess it cuts more as well.
if people don't know it already, this stuff has major applications when it comes to banks. pretty much what banking comes down to is judging that spin when the ob hits the cushion. whaterver throws the ball the most must also apply more english, that's wht i asked about draw vs follow and what people thought about that.
edit: i have noticed over the years, even pros, when they have a tougher shot (usually a longer shot) and they are following with the cueball, they will many times hit the outside of the pocket, and many times overcut it too, if they do in fact happen to miss.
so, i read the post and was still a bit unclear on one point. does follow or draw cut the ball more?
to back up what people have said, a rolling ball has always cut the ball a little more, i have to aim a bit fuller. for me, when i draw the ball and there is a substancial angle, i almost always apply at least a quarter tip or so of outside... so, i'm not that familiar with what a center ball draw stroke will do on a cut, but as people have stated, i guess it cuts more as well.
if people don't know it already, this stuff has major applications when it comes to banks. pretty much what banking comes down to is judging that spin when the ob hits the cushion. whaterver throws the ball the most must also apply more english, that's wht i asked about draw vs follow and what people thought about that.
edit: i have noticed over the years, even pros, when they have a tougher shot (usually a longer shot) and they are following with the cueball, they will many times hit the outside of the pocket, and many times overcut it too, if they do in fact happen to miss.
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Spinning
Wow..And all i thought i had to do was hit the ball in the correct line to the pocket and pray..Gives a whole new meaning to "confusion"...LOL...Very interesting...Don
Wow..And all i thought i had to do was hit the ball in the correct line to the pocket and pray..Gives a whole new meaning to "confusion"...LOL...Very interesting...Don
Jal said:
If you invoke an advancing ball with side spin rubbing sideways on the ridge of cloth in front of it, I see no reason why the curving would stop until either the ball stopped spinning or it just stopped completely. I don't see that there would be any equilibrium state.
In the old days, when billiard cloth had nap, and some of the balls were ivory, players worried about the direction the ball would curve at the end due to the nap. Some snooker players still worry about that.
I don't think I've ever seen spin-induced curving on worsted cloth. Or at least, I've never noticed an effect. Can you describe an experiment in which it could be observed? The standard counter-proof is to set a ball rapidly spinning in place and tap it with another ball. The observation is that it seems to go in a straight line.
So, following on the general principle that it's unfair to ask of others something you are unwilling to do yourself, I got myself to a table last night. Both draw and follow reduce throw significantly on a 30-degree cut (half-ball hit) compared to a non-spinning cue ball. The results were quite consistent. The difference was about 3 degrees. For a long bank shot, the difference is 10 inches in where the object ball lands after going about 14 diamonds (up and back).Bob Jewett said:
I think some other participants here need more time on the table and less at their computer.
For details on the experiment, see my May(?) 2006 column in Billiards Digest.
If you're thinking about any of this stuff when you pull the trigger, I can almost guarantee you'll miss the shot. Most players develop a feel for shots and make the corrections in their subconscious, where it belongs. I think all these physical details are useful only if you are having problems and trying to diagnose them.Poolshootindon said:
Until I did the experiment last night, I didn't really know how draw and follow would change the cut angle, although I did trust the theory (from Ron Shapard and Dave Alciatore) to be fairly close. It turns out that the theory is right.
The effect was close to equal, in my measurement. This is also what theory predicts, pretty closely.enzo said: