effect bottom has on an object ball when cutting?

goingproin07

AzB Silver Member
Silver Member
on this shot, i can make it 10 outta 10 times, but if i try the same shot with alot of bottom i always miss. So my question is, does bottom make the ball cut more, or less?


CueTable Help

 
Not trying to be snarky here, but... when you miss that shot, does it hit the side rail or the end rail? If it hits the side rail, it's cutting more - if the end rail, it's cutting less.

When you try that shot, does it always miss the same way?
 
seems like i remember a thread where someone says bottom effects the cut. I dont aim any different whether im using bottom or top, if i had to guess id say you arent hitting the cueball dead in the center, if you hit the slightest bit to the right or left at the base of the cueball you cause immediate squirt which means the cueball isnt hitting the object ball where youre aiming. that would be my guess.
 
Alignment

I have to agree with scottycoyote here, bottom shouldn't effect the OB path only the CB path. I think there must be something up with your alignment that's making you hit the CB off the Vertical center when you put bottom spin on.

Are you Jacking your cue up?
 
Good Topic
I am going to try this tonight.
I am wondering if you are making the shot with smooth follow vs a hard draw?
 
My guess it's an alignment problem.

When playing this shot as a run through, you probably play a touch of OE, so you line up thicker than the natural pot angle.

When you play low, you cannot hit so far off center.

To diagnose this, you need to explain your experience in what side you usually miss to.

btw: I don't think the change in SIT is very much on these shots. I align them the same, and lower bridge afterward.
 
jsp said:
You just missed this thread...

http://forums.azbilliards.com/showthread.php?t=26535

The general consensus is that draw reduces throw. The jury is still out whether follow increases or reduces throw.
Hi Jsp. I mentioned in that thread some effects that a poster ("Cushioncrawler" on the CCB forum) has figured should be present, and that I wasn't sure how large these effects might be. A graph comparing them to the concomitant throw angle is here:

OB_Masse.jpg


In the diagram, the friction direction ranges from 0 - 180 degrees when there is draw on the cueball, and from 180 - 360 degrees for follow. The throw angle is based on an average value of .06 for the coefficient of friction, and it's assumed that there is enough spin on the cueball so that it doesn't end up rolling across the object ball. In other words, it represents a subset of actual throw realities.

The "follow/draw masse angle" is due to the fact that the object ball's acquired spin axis (from the impact) is not initially normal to its direction of travel when there is either draw or follow on the cueball as well as some sideways throw due to cut angle and/or spin. Draw masse always decreases the apparent throw while follow masse increases it.

The "spin masse angle" is irrelevant here but is due to the fact that the object ball is constantly "climbiing up" the cloth fibres. So even if its english component is perfectly perpendicular to the slate, it's nevertheless at a slight angle, effectively, with respect to the cloth. I calculated this angle to be 0.58 deg for 100 speed cloth.

As you can see, these effects are very small and are multiplied by four in the picture to get them to show up a little better. Even if you're one to obsess about throw, you probably shouldn't worry about them :}

I should emphasize that these may or may not be in line with Cushioncrawlers interpretation and he may thus come up with different magnitudes for these effects. Also, while I tried to be careful, this is the first time I've looked at this (I wasn't even aware of their existence untill Cushioncrawler pointed them out) so there is the possibility that they're not quite right.

Jim
 
Jal,
So on the shot diagrammed, what's your estimate of difference in entering the pocket for roll versus stun versus draw.

Assume stun goes in middle pocket. Will the other spins vary more than 1" to the overcut side of this line? What about at speed?
 
Interesting result. Does it follow that you can't get much more masse effect if the cue ball is a little in the air when it hits the object ball?

Jal said:
... The "spin masse angle" is irrelevant here but is due to the fact that the object ball is constantly "climbiing up" the cloth fibres. So even if its english component is perfectly perpendicular to the slate, it's nevertheless at a slight angle, effectively, with respect to the cloth. I calculated this angle to be 0.58 deg for 100 speed cloth.

Would this cause the path to curve as long as the ball has sidespin? Does this make a prediction for a (cue) ball rolling to a stop with excess side?
 
Center ball, is center ball, it would not matter if you cued high, middle or low, as long as the cue was level and the follow through was the same.
If you are jacked up, you could be jumping the cue ball into or on the object ball and affecting its cut angle then a lot.
 
yrraltsafone said:
Center ball, is center ball, it would not matter if you cued high, middle or low, as long as the cue was level and the follow through was the same. ...
The physics predicts that the throw will be maximum if the cue ball doesn't have any draw or follow. That's because the firction between the cue ball and the object ball has a maximum total value when the balls are slipping against each other, and if the direction of that slip is all to the side, the throw will be largest. If there is draw or follow in addition to the sideways rubbing, the follow or draw will take up part of that maximum rubbing and there will be less of the rubbing to cause throw.

That's the theory, anyway. I'm not sure anyone has ever made a measurement of this. It's not so easy to prepare a cue ball with a known amount of spin and run it into an object ball at an exact location, speed and angle. You can get it close by hand -- you do all the time when shooting -- but to do it exactly needs some kind of fixturing.
 
Bob Jewett said:
The physics predicts that the throw will be maximum if the cue ball doesn't have any draw or follow. That's because the firction between the cue ball and the object ball has a maximum total value when the balls are slipping against each other, and if the direction of that slip is all to the side, the throw will be largest. If there is draw or follow in addition to the sideways rubbing, the follow or draw will take up part of that maximum rubbing and there will be less of the rubbing to cause throw.

That's the theory, anyway. I'm not sure anyone has ever made a measurement of this. It's not so easy to prepare a cue ball with a known amount of spin and run it into an object ball at an exact location, speed and angle. You can get it close by hand -- you do all the time when shooting -- but to do it exactly needs some kind of fixturing.
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Then you don't know, and if you don't know, what does all this mean. Does it mean, nothing, confusion?
Why don't you run tests, then come back and teach us something new.
You got the answer, center ball, is center ball.
 
So Bob, are you saying that if you are using Low Left, High Left, Low Right or High Right you will have less throw because these methods of hitting the cue ball create less friction between the cue ball and the object ball than if you use similar SIDE ENGLISH ONLY or even whether you use high only, low only are center ball, correct?

So if you are playing on a table that has dirty balls and skidding is a problem you would be better off using a combination of HIGH/LOW with side English, rather than just Center ball, Side English Only, Just High only or Just low only?

Maybe I didn't word this correctly but hope you get my questions.

Thanks,
JoeyA

Bob Jewett said:
The physics predicts that the throw will be maximum if the cue ball doesn't have any draw or follow. That's because the firction between the cue ball and the object ball has a maximum total value when the balls are slipping against each other, and if the direction of that slip is all to the side, the throw will be largest. If there is draw or follow in addition to the sideways rubbing, the follow or draw will take up part of that maximum rubbing and there will be less of the rubbing to cause throw.

That's the theory, anyway. I'm not sure anyone has ever made a measurement of this. It's not so easy to prepare a cue ball with a known amount of spin and run it into an object ball at an exact location, speed and angle. You can get it close by hand -- you do all the time when shooting -- but to do it exactly needs some kind of fixturing.
 
Hey Jal...thanks for the post.

Jal said:
...The "follow/draw masse angle" is due to the fact that the object ball's acquired spin axis (from the impact) is not initially normal to its direction of travel when there is either draw or follow on the cueball as well as some sideways throw due to cut angle and/or spin. Draw masse always decreases the apparent throw while follow masse increases it.
So, in other words, I was originally correct...that follow does increase the effects of throw {pumping my fists in the air}. :D

I understand these differences in throw between hitting with follow and draw are too minute to be practically compensated for (as opposed to side english), but the differences are there nonetheless.
 
jsp said:
Hey Jal...thanks for the response.


So, in other words, I was originally correct...that follow does increase the effects of throw {pumping my fists in the air}. :D

I understand these differences in throw between hitting with follow and draw are too minute to be practically compensated for (as opposed to side english), but the differences are there nonetheless.

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The answer is, using a level cue, with a level follow through, the cue does not dip down, center ball is center ball, high, center or low.

Jack up, its all different, you are hitting now jump shots jumping up on the cue ball at always different heights which always twists the ball with extreme English.
 
yrraltsafone said:
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The answer is, using a level cue, with a level follow through, the cue does not dip down, center ball is center ball, high, center or low.
I still have absolutely no idea what you mean by this. What do you mean exactly by "center ball". Be specific please.
 
funny how no one's thinking of the effects of transfer of spin on the OB....draw in this case would possibly spin the OB past or undercutting the ball...
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goingproin07 said:
on this shot, i can make it 10 outta 10 times, but if i try the same shot with alot of bottom i always miss. So my question is, does bottom make the ball cut more, or less?

Instead of using the cueball, shoot the same shot using a striped ball as the cueball. Be sure the stripe is perpendicular to the cloth. Upon shooting see if the the striped ball gives any indication of sidespin. Often what happens when someone uses draw it is possible to apply sidespin because the cue is not hitting the center of the ball. This could throw the object ball off it's intended path.
What also could be happening is you may be elevating the stick in trying to apply draw. If indeed you are and again you hit the stripe/cueball off center it will cause the ball to squirt off the intended path.
 
My stroke has these effects. I have tested these greatly and am 100% sure of it.

If I use draw, I have to aim fuller. This is true up to a certain angle. Once the angle gets to a certain point, I do not need to compensate.

The slower I hit the CB, the more I need to compnsate. If I really stroke the CB, the OB will cut much farther...


To test this, place the OB 2 feet from the pocket and the CB 2 feet from the OB at a slight angle. Aim slightly off center with center ball to make the shot. Now move the CB over a couple inches and aim for the EXACT same spot but use draw. I would pocket the ball or even over cut the bal.

I can really over cut the ball if I stroke it well and this is aiming slightly off center where I would under cut the ball if I was using dead center.


Top spin - I have to over cut to make the OB. The angle rules are the same. Up to a certain angle, no compensation is needed. Compensation is much less that with draw.

Draw has a greater effect than top but both need compensation.


I believe these are rules of physics that my stroke creates. I am pretty sure my stroke is straight and true.

Why do I think this happens? It is the transfer of spin to the OB. The spin put on the ball curves its path. If I hit the ball low enough and slow enough, I can actually see the OB "bend" off its line. Thinking about the spin the OB has makes me think it is backwards, to what I am saying, but nonetheless, it is the best explaination I have come up with.


I discovered this while creating an aiming system that mathematically works perfect. Adding physics to it makes it flawless. I found many phenomenons that caused me to adjust from my system. This was one of them and I am 100% sure of my results, YMMV....
 
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