Paging Dr. Dave! How did this scratch?

Tin Man

Tin Man

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OK, I didn't see this first hand so I'm at the mercy of the person who set it up and described what happened. See diagram below. The 8 ball was frozen and he had a little angle, not a lot, but enough to be confident that there was no scratch in play.

Or so he thought. Apparently he shot the 8 ball cleanly into the pocket and the cue ball ran straight down the rail and followed it in. Now, some nuance to what he said happened. He shot it neither hard, nor soft. He didn't slow roll it and it just rolled off. Nor did he firm stroke it where it peeled out. He said that both he and his opponent were amazed because the cue ball never left the rail at all. The speed was a soft/medium, enough to confidently float down to the end rail. Table conditions were fairly new but broken in cloth.

He asked me how that could happen. I came up with a bunch of theories but I don't think I really understand it.

1) Maybe the rail groove trapped the cue ball. He seemed skeptical because the cloth isn't very worn and it never left the rail at all, it seemed glued the entire time.

2) Overspin, maybe the thick hit with topspin caused it to peel out just a touch to change the natural path of the cue ball.

3) Left spin. Maybe he caught the 8 a little thick with left spin and the thick hit and spin somehow got it to stick to the rail (I'm picturing the shot where the cue ball is frozen to the side rail and you have to slightly masse around the side pocket with inside spin and it sticks to the rail).

4) Slight rail first hit. Maybe he caught the rail first just enough to catch the 8 really thick from the rail side and follow it straight. I've done this on not frozen shots where I go rail first but follow it in due to a thick hit.

Any thoughts? I'd love to learn something!

1746167291871.png
 
Tin Man said:
OK, I didn't see this first hand so I'm at the mercy of the person who set it up and described what happened. See diagram below. The 8 ball was frozen and he had a little angle, not a lot, but enough to be confident that there was no scratch in play.

Or so he thought. Apparently he shot the 8 ball cleanly into the pocket and the cue ball ran straight down the rail and followed it in. Now, some nuance to what he said happened. He shot it neither hard, nor soft. He didn't slow roll it and it just rolled off. Nor did he firm stroke it where it peeled out. He said that both he and his opponent were amazed because the cue ball never left the rail at all. The speed was a soft/medium, enough to confidently float down to the end rail. Table conditions were fairly new but broken in cloth.

He asked me how that could happen. I came up with a bunch of theories but I don't think I really understand it.

1) Maybe the rail groove trapped the cue ball. He seemed skeptical because the cloth isn't very worn and it never left the rail at all, it seemed glued the entire time.

2) Overspin, maybe the thick hit with topspin caused it to peel out just a touch to change the natural path of the cue ball.

3) Left spin. Maybe he caught the 8 a little thick with left spin and the thick hit and spin somehow got it to stick to the rail (I'm picturing the shot where the cue ball is frozen to the side rail and you have to slightly masse around the side pocket with inside spin and it sticks to the rail).

4) Slight rail first hit. Maybe he caught the rail first just enough to catch the 8 really thick from the rail side and follow it straight. I've done this on not frozen shots where I go rail first but follow it in due to a thick hit.

Any thoughts? I'd love to learn something!

View attachment 822480
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Junk on the table, dead spot in rail, chalk mark changing cb attitude on contact, dirty balls... Personally I think he had some unintended left on there and came off rail a tad too soon.
 
My idea is a combination of:

1. Misjudging/misremembering the angle, was probably slightly fuller than he described.
2. Hitting it with top, possibly slight overspin of follow but might even happen without it
3. Trace of left spin to throw the OB a bit allowing a slightly fuller hit while still potting the OB
4. New cloth, pocket plays bigger
5. Table roll, there's an increased risk for table roll errors along the rail grooves.

With the first 3 factors alone, the CB angle would barely change, but still be enough to miss the pocket. But a slight table roll, which is very typical at such speeds near rail grooves, would be enough to cause the scratch, especially on a new cloth with pockets that play bigger.

Junk on the table is also a possibility, but not necessary.
 
Tin Man said:
2) Overspin, maybe the thick hit with topspin caused it to peel out just a touch to change the natural path of the cue ball.
Click to expand...
Without being able to see how he cued it up. This is the most likely based on my exposure to similar situations. Far more likely to happen and infinitely easier to do on fresh cloth.
 
lfigueroa said:
Over spin at medium speed will do it, especially on newer cloth.

The actual angle was probably a little less.

Lou Figueroa
bigger pockets will help
but not essential
Click to expand...
agree, the actual angle was shallower than in that diagram. Any follow at all on fresh cloth and the cb will do that.
 
Not that I can really explain it, but as others note and from experience there's a wider range of angles where you can follow the ball into the pocket on a shot like this than you'd expect. "No way I can follow it in on this one!" Followed by a scratch, or the CB getting hung up in the jaws.
 
jasonlaus said:
My question is, why would they follow it in the first place?
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Maybe even a better question is why you question the choice...?..., lol

My guess is the intention was to hit two rails and get a BIH shape on the 9. The vast majority will take seemingly easy opportunities to get the CB away from the rail for the next shot. Guy just hit bad is all. No real mystery here
 
Mensabum said:
Junk on the table, dead spot in rail, chalk mark changing cb attitude on contact, dirty balls... Personally I think he had some unintended left on there and came off rail a tad too soon.
Click to expand...
Out of all the answers, I come back to debris on the table, chalk or a tiny clip of staple, even a grain of salt can do it.
 
I get these situations at times on my Gold Crown IV. I just shake my head and usually yell out loud about how that can't happen and how that defies the laws of physics. They usually mess up a runout for me.

r/DCP
 
Possibly a little skid from the CB and being pinched between the 8 and the rail was enough.

Had one of these a couple weeks ago. Playing the 5, going under the 10 for position on the 6 up table (only reset the 3 balls pictured, so may not be 100% accurate but close enough). Somehow hugged the near jaw of the side and tipped in while i was standing there staring at it.

I've always been good at finding creative ways to scratch...
1746206213073.jpeg
 
I scratched on a shot very similar to this just this week. I had plenty of room to play the CB across table but I was practicing by myself and the 8 and 9 were the only 2 balls left on the table. I decided to try and spin the CB down the rail to get short side shape on the 9 which was maybe 10 inches off the side rail. I hit the 8 a little fat and the CB went straight down the rail and scratched. If I had been playing seriously I would have just played across but you only learn by trying different things.
 
He asked me how that could happen.
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You should have responded curtly: "hydraulics", then turned your back and sauntered away.

Hitting the same shot in the US Open, SVB almost scratched twice in three shots: he got lucky when his first shot didn't scratch, but he didn't learn anything when he had the same shot again after making a ball, and this time he did scratch--giving his opponent ball in hand on the 9-ball. Dr. Dave explains it all in the following video:

 
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The_JV said:
Maybe even a better question is why you question the choice...?..., lol

My guess is the intention was to hit two rails and get a BIH shape on the 9. The vast majority will take seemingly easy opportunities to get the CB away from the rail for the next shot. Guy just hit bad is all. No real mystery here
Click to expand...
So again, why follow it
 
A touch of right hand English along with the follow at a speed just enough to get the cue ball to the pocket will cause the scratch.

The location of the cue ball can lend itself to a softer angle as well, which will lead to the possibility of a scratch.
 
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My question is: how close to the cushion does the cue ball have to be on that table to scratch one in 50?

Most likely: misremembered
Next: large pocket and a full hit
Maybe: dead spot on the cushion

There is a similar scratch when both balls are farther from the cushion and you shoot harder. The cue ball ball hops a little and hits the nose just wrong and follows straight to the pocket.
 
Tin Man said:
OK, I didn't see this first hand so I'm at the mercy of the person who set it up and described what happened. See diagram below. The 8 ball was frozen and he had a little angle, not a lot, but enough to be confident that there was no scratch in play.

Or so he thought. Apparently he shot the 8 ball cleanly into the pocket and the cue ball ran straight down the rail and followed it in. Now, some nuance to what he said happened. He shot it neither hard, nor soft. He didn't slow roll it and it just rolled off. Nor did he firm stroke it where it peeled out. He said that both he and his opponent were amazed because the cue ball never left the rail at all. The speed was a soft/medium, enough to confidently float down to the end rail. Table conditions were fairly new but broken in cloth.

He asked me how that could happen. I came up with a bunch of theories but I don't think I really understand it.

1) Maybe the rail groove trapped the cue ball. He seemed skeptical because the cloth isn't very worn and it never left the rail at all, it seemed glued the entire time.

2) Overspin, maybe the thick hit with topspin caused it to peel out just a touch to change the natural path of the cue ball.

3) Left spin. Maybe he caught the 8 a little thick with left spin and the thick hit and spin somehow got it to stick to the rail (I'm picturing the shot where the cue ball is frozen to the side rail and you have to slightly masse around the side pocket with inside spin and it sticks to the rail).

4) Slight rail first hit. Maybe he caught the rail first just enough to catch the 8 really thick from the rail side and follow it straight. I've done this on not frozen shots where I go rail first but follow it in due to a thick hit.

Any thoughts? I'd love to learn something!

View attachment 822480
Click to expand...
It's possible he unknowingly "torqued/twisted" his stroke at impact, with just enough high/follow spin to trail the 8 ball down-rail. A golf coach who's name escapes me used to say that "your golf ball was your best coach." When you hit a ball, generally speaking in any sport, the ball will tell you what you did right/wrong, etc. Obviously, his cue ball traveled forward to his surprise. He knows that, because the ball told him.
😉
 
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