Can you overcut an object ball frozen to the rail?

Jaden said:
If you can show a CB hitting the rail, striking the OB and continuing to compress the rail without hitting the OB a second time...
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Jaden, there is no reason to believe it should strike the OB a second time. The parallel component of the cueball's velocity is nearly completely removed by the first impact with the OB.

Jaden said:
All I've been saying is that you can't cut the ball at greater than a perpendicular angle to the rail without hitting the rail first or employing throw and that anything else should be called a kick into the ball because you're hitting the rail first.
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Ignoring throw, I don't think anyone has said that you can "overcut" the OB without the CB contacting the cushion first. We all agree on that, no? The issue, apparently for some such as yourself, is whether this should be termed an "overcut" or a "kick." Overcut seems appropriate (to me), particularly when CB-OB impact takes place during compression, as opposed to decompression, but it is just a question of semantics.

Jim
 
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Jaden said:
http://billiards.colostate.edu/high_speed_videos/new/HSVA-129.htm

That one clearly shows that the OB hits and rebounds from the rail.

The question was if you could overcut the OB without it hitting the rail.

http://billiards.colostate.edu/high_speed_videos/new/HSVA-132.htm

The one above is clearly a kick. The CB hits the rail and hits the OB on it's way out.

http://billiards.colostate.edu/high_speed_videos/new/HSVA-136.htm

This is the only one that comes close to illustrating Patrick's equivocation and it still seems to be hitting the ball on the rebound, not mid stream.

http://billiards.colostate.edu/high_speed_videos/new/HSVA-137.htm

The above would be an iulustration of it, if it weren't for the draw, the CB is actually coming off the rail and upon contact the draw along with running english is pulling it slightly back into the rail before rebounding back out.
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Agreed. HSV A.137 clearly shows an overcut caused by ball contact during cushion compression. If the OB were far enough from the pocket and/or if the pockets were "tight," this shot could miss by a lot.

Jaden said:
Plus none of these shots show the ball coming away from the rail enough to miss the pocket
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Exactly! The purpose for this collection of clips was to show how much CB control you can have with a rail cut shot, while still pocketing the OB (although, the OB was fairly close to the pocket). I have a feature on this topic on my HSV DVD.

In HSV A.137, the running (inside) English might actually help the OB stay close to the rail. The spin-induced throw is towards the rail, compensating for the over cut. If reverse (outside) English were used instead, the OB could be over-cut even more. If people are still interested, I can try to capture several examples (with and without English) of over-cuts caused by rail compression. I can get a closer-up view with the high-speed camera and simultaneously capture a large view with my regular camera showing the shots being missed.

Regards,
Dave
 
pooltchr said:
When all is said and done, it really doesn't matter. If you don't hit it right, you are going to miss the shot.
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This is certainly a statement that everybody in this thread can easily agree with.

Good job,
Dave
 
Jal said:
Ignoring throw, I don't think anyone has said that you can "overcut" the OB without the CB contacting the cushion first. We all agree on that, no? The issue, apparently for some such as yourself, is whether this should be termed an "overcut" or a "kick." Overcut seems appropriate (to me), particularly when CB-OB impact takes place during compression, as opposed to decompression, but it is just a question of semantics.
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Good summary Jim. I think you are right that a lot of "debate" in this thread was simple a result of "semantic differences."

Regards,
Dave
 
hdgis1 said:
Ideally I'd think one would make contact with ball and rail at same time.
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This is a common misconception for how to make a rail shot that has been mentioned a few times in this thread already but wasn't directly addressed by the "science guys" yet. I think it's adding to the confusion for some so I'd like to briefly address it.

Making contact with the ball and the rail at *exactly* the same time - which is difficult to do, btw - would throw the object ball into the cushion because of the friction between balls. You can put an amount of outside english on the CB to cancel the effect, but the exact amount changes with cut angle and can be hard to reproduce consistently.

Interestingly, a simultaneous hit with this canceling/rolling/natural outside spin (Dr. Dave likes to call it "gearing") is not the ideal way to shoot a rail shot when all you want to do is maximize your chances of pocketing the ball.

I see a lot of people try to juice it with hard english and hit the rail first which in effect changes the cut approach by ninety degrees. Then depending on how far the ball is from the hole, I'd say you can 'over cut' it.
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Hitting the rail first does not change the cut approach by any fixed angle like 90 degrees. The amount it changes the cut depends mainly on the incidence angle, the cushion efficiency, and the cue ball's spin and speed (and thus the ball-cushion friction.) Rail shots are really complicated with lots of little interesting-but-tedious details to consider. There are many past threads discussing them, and it's worth searching them out.

Once all the little frictional details (which depend on whether you're compressing/decompressing at OB contact) as well as the pocket distance and effective size are considered (so you know the center of the effective target you're trying to hit), it turns out that you can maximize the margin of error by always hit the rail a little first at a distance along the cushion and with a spin (which ranges from outside to none to inside) that depends on cut angle and speed.

Byrne made brief mention (via Bob Jewett) of some of these details in a few pages in his books, but Jack Koehler was first to discuss it in depth in his "The Science of Pocket Billiards" where he devoted an entire chapter to it. Dr. Dave has subsequently provided his own in-depth analysis with all the fun high speed videos to go along with it.

Robert

btw, I'm in the camp that considers OB contact during compression to still be over-cutting the ball :)
 
pooltchr:
I don't think we are even discussing english, just whether ot not the cue ball can get in behind the object ball and the rail to actually overcut the ball before the cushion alters the direction of travel for the cueball.
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I don't think that's really in question, but if so then there are really four questions:

1. The original poster's question: Can an OB be cut away from the rail without "banking" it (no matter whether the CB is moving into or out of the rail)? [ANSWER: Yes]

2. Your question: Can the CB overcut the OB before the cushion alters the CB's direction of travel? [ANSWER: No, because the CB's direction of travel is altered the moment it hits the cushion.]

3. Can the CB contact the OB after initial rail contact while it's still compressing the rail? [ANSWER: Yes]

4. Should it be called a "cut" or a "kick" if the CB contacts the OB while it's compressing the rail? [MY OPINION: "cut", but who really cares about that?]

pj
chgo
 
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Id agree with Jaden and Steve here.

I understand what PJ is saying, but per the OP question I would say no.

His question is could it be cut away from the rail? With PJ's example, even if you had the cueball continuing to compress the rail and hit the OB on the back side wouldnt the CIT make the OB go into the rail?

I usually try and stay away from posting in these threads, but I was surprised someone hadnt mentioned the throw considering the speed of the example to compress the rail.

Woody
 
woody_968 said:
With PJ's example, even if you had the cueball continuing to compress the rail and hit the OB on the back side wouldnt the CIT make the OB go into the rail?

I usually try and stay away from posting in these threads, but I was surprised someone hadnt mentioned the throw considering the speed of the example to compress the rail.
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Max CIT is much less than where you can cut the ball compressing the cushion. Also, the higher speed reduces the throw.

Robert
 
woody_968:
I was surprised someone hadn't mentioned the throw
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From post #19:

If it hits the OB closer to the rail than 1/2 ball then the OB must cut away from the rail unless collision-induced throw is as great as the cut angle. The cut angle in the drawing is almost 10 degrees, about twice the maximum angle of throw.
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pj
chgo
 
Samiel said:
If an object ball is frozen to the rail, can you overcut it and miss the pocket completely? I figure you can overcut it a little by bending the rail slightly before contact, but is that overcut enough to miss the pocket by?

Another way of asking this is, when an object ball is frozen to the rail, can you miss the shot by not driving the object ball into the rail? I figure you can always miss the shot by undercutting the object ball and driving it into the rail, but overcutting would cause the object ball to not hit the rail.

My thought is that you should always be able to make the object ball if you never undercut it.
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NO The polar ice caps will melt before you can over cut a ball frozen on the rail.
 
what if?????????

What if the rail was solid stainless steel and non-compressable could the object ball be overcut then?:wink:

Never try to teach a pig to sing. You just waste your time and you piss off the pig.
 
This entire thread makes no sense when it comes to practical application for a player of any real ability.

I would guess PJ is likely right; however two things jump out in my mind:

1) Only a moron would shoot at the OB in that fashion if they're really trying to make the ball

2) The % of actually contacting the OB in the fashion that PJ diagrams is so small, the moron would have to get lucky

So, is it possible... probably. Is it something to be concerned about... no way. I'm surprised this thread made it by page 2. We're arguing over stuff that's so retarded, we're nitpicking. We're picking fly shit out of pepper here.

Dave
 
I really enjoy the threads that prove which of the members of this forum are, in fact, stupid. It helps me in threads where I'm the one looking for answers or advice, so that I know who I should pay attention to.

-Andrew
 
Wow, I didn't expect this thread to go this long, lol.

My original question was answered, although I may not have asked it very well. Really, what I wanted to know was, if the object ball is frozen to the rail, can you hit the object ball such that you cause the object ball not to hit into the rail. The answer is yes, because you can compress the rail before or during contact, causing the object ball to be driven away from the rail. I didn't ask about english, but I assume you can also throw the object ball away from the rail. Both of these scenarios can cause the object ball to miss the pocket.

Of course it makes me wonder how hard I would need to hit the rail to make it compress enough to do this, but I guess that's another thread! :p

Thank you for all the answers and analyses!
 
Neil said:
Here's something for you guys to ponder- ever play with the huge oversize cue balls? Ever try and run a ball down the rail with one of those? The only way you could do it was to compress the rail BEFORE making contact with the ob.


Your dead wrong saying "only way was to compress the rail". When using the Big Ball to make object ball down the rail and into the pocket, you load up whitey with outside center spin, hit the undercut angle and the Big Rock steer/cuts the object ball straight into the pocket. Bernardo/Ether taught me that long ago in So. Cal.
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Samiel said:
Wow, I didn't expect this thread to go this long, lol.

My original question was answered, although I may not have asked it very well. Really, what I wanted to know was, if the object ball is frozen to the rail, can you hit the object ball such that you cause the object ball not to hit into the rail. The answer is yes, because you can compress the rail before or during contact, causing the object ball to be driven away from the rail. I didn't ask about english, but I assume you can also throw the object ball away from the rail. Both of these scenarios can cause the object ball to miss the pocket.

Of course it makes me wonder how hard I would need to hit the rail to make it compress enough to do this, but I guess that's another thread! :p

Thank you for all the answers and analyses!
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You don't have to hit hard at all. To get enough of a cut to compensate for the countereffect of throw you only have to compress the rail about 1/10 of an inch or so. To get the kick effect (hitting the OB as the cushion is uncompressing and kicking the CB out) you can hit as softly as you want, because then throw isn't a counterfactor.

pj
chgo
 
Island Drive said:
Your dead wrong saying "only way was to compress the rail". When using the Big Ball to make object ball down the rail and into the pocket, you load up whitey with outside center spin, hit the undercut angle and the Big Rock steer/cuts the object ball straight into the pocket.
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This is definitely possible. For example, with a 2-3/8"D big cue ball and 2-1/4"D object ball, the centers are aligned ~1.6 degrees into the rail when both are frozen to the cushion and to each other. You can easily hit the ball before the rail and throw it the 2-3 degrees or so needed to send it down the rail into the pocket, especially with fuller hits. Clean balls and higher speeds make it tougher, though.

Btw, the center spin is used because throw is maximized when using stun (follow and draw both reduce throw.)

Robert
 
Robert Raiford said:
This is definitely possible. For example, with a 2-3/8"D big cue ball and 2-1/4"D object ball, the centers are aligned ~1.6 degrees into the rail when both are frozen to the cushion and to each other. You can easily hit the ball before the rail and throw it the 2-3 degrees or so needed to send it down the rail into the pocket, especially with fuller hits. Clean balls and higher speeds make it tougher, though.

Btw, the center spin is used because throw is maximized when using stun (follow and draw both reduce throw.)

Robert
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If you say its definitely possible, then is it also possibly definite?

There's no ifs or buts about it....
It "does" happen, plain and simple.
 
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