An odd discovery

JC

Coos Cues
I was practicing kicks on my diamond pro table and found something unexpected.

Cue ball placed in jaws of corner pocket aiming right at the second diamond medium stroke center ball and it come up short of the side. Hit it a bunch and it's short every time. Move over to the jaws of the side pocket and kick back to the same corner and it goes in center pocket every time aiming at the same diamond. Not at the rail in front of the diamond but right at the diamond. Then I put a piece of chalk on the diamond to make sure I was aiming there.

So then I kick at the other corner from the same side pocket and it comes up short just like when I was kicking to the right at the side pocket. Move over to that corner and kick back to the left at the side and it's center pocket. Now I'm wondering what's wrong with my table? So I go to the other side and try it. Same result, kicking right it's all short, Kicking left center pocket.

It was then i realized it might be my contact point on the cue ball. I might be cuing english without seeing it. So I go to the spot and hit them up and back and the cue ball isn't deflecting to either side at the rail. Now I'm really confused so I kick some more from corner to side and side to corner and it's always hitting short to the right and longer to the left.

It has to be me right? It can't be the table.

I am going to set up the shots and have a buddy do the kicks to see how it plays for him next chance I get.
 
Interesting. If you do have your friend try you should record it so everyone can see what's happening. A picture speaks a 1000 words.
 
If you are aiming at the diamond and not the nose of the rail straight out from the diamond then you are hitting two completely different points on the cushion for the two shots.

On top of that, the second diamond (to me that would mean the point on the cushion nose in line with it) is not the perfect aim/contact point for these shots. The diamond is half way between center of the side pocket and the far edge of the corner pocket (the short) cushion, not the heart of the corner pocket.

The bank point for your shot from the side pocket should actually be short of (to the shooter's side) the diamond and by aiming at the diamond you are correctly (inadvertently) hitting the cushion short of it and making the shot. When you shoot from the heart of the corner you actually need to hit the cushion a hair beyond the diamond (again, I mean the nose of the cushion in line with the diamond and it's the same point on the nose as the other shot). By aiming at the actual diamond you are actually on the wrong side of it where you hit the nose....you should miss short of the side every time.
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One way to eliminate yourself is a guide block for your cue to sit in or a pair of rests. Then push from the end and see what happens. Now you are not holding the cue in any way and not making any influences. Try the same on the other side. If it is still the same, it could be the rail and table.
 
If you are aiming at the diamond and not the nose of the rail straight out from the diamond then you are hitting two completely different points on the cushion for the two shots.
Because a rolling CB curves a little long after rebound, it’s necessary to hit slightly short - aiming at the diamond rather than the cushion nose is one correct way to do that.

On top of that, the second diamond (to me that would mean the point on the nose in line with it) is not the perfect aim point for either shot. The diamond is half way between center of the side pocket and the far edge of the corner pocket (the short) cushion, not the heart of the corner pocket.
The two cushion noses are cut short to make the pocket opening - where they would intersect is in the heart of that pocket opening. So dividing the distance to the end rail in half is the correct target both ways (adjusted a little short for rolling curve after rebound).

pj
chgo
 
Because a rolling CB curves a little long after rebound, it’s necessary to hit slightly short - aiming at the diamond rather than the cushion nose is one correct way to do that.


The two cushion noses are cut short to make the pocket opening - where they would intersect is in the heart of that pocket opening. So dividing the distance to the end rail in half is the correct target both ways (adjusted a little short for rolling curve after rebound).

pj
chgo
That's somewhat true but he'd have to be setting them up like this for it really to be the same shot in both directions.
2272193f984bc576f0e8beafa9fa4a0a.jpg
c5d126b571c6a05baf534e4c8a49e500.jpg


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...he'd have to be setting them up like this for it really to be the same shot in both directions.
You're right that the intersection of the rails is slightly longer than the middle of the corner pocket opening (the white dot below), although probably not enough to matter (and less and less difference as the kick angle widens).

But the side pocket's spot, for both shooting to and from, is almost on the center of the pocket opening - probably only about 1/2" away from dead center (same offset shown for the corner pocket), and it's offset toward the corner, not away from it (can't tell if that's what you meant with your pic). I think these adjustments are usually too small to bother with.

pj
chgo

The white square below, exactly 50" on each side, shows the "equal angle" geometry. Rolling kicks have to be aimed a little short (say, at the diamond on the rail) to compensate for "forward roll masse".

P.S. I like the strings for illustrating this - good idea.

equal angle.jpg
 
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That's somewhat true but he'd have to be setting them up like this for it really to be the same shot in both directions.
2272193f984bc576f0e8beafa9fa4a0a.jpg
c5d126b571c6a05baf534e4c8a49e500.jpg


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Maybe the real learning for me is that I have always misunderstood the table/pocket geometry? But the discrepancy is larger than this.

The shots to the right side are not coming up a fraction short, they are coming up way short though. And why then when I shoot the same shot on a mirror image the other direction the side pocket isn't short?

I will make a video showing it
 
You're right that the intersection of the rails is slightly longer than the middle of the corner pocket opening (the white dot below), although probably not enough to matter.

But the side pocket's spot, for both shooting to and from, is exactly in the center of the pocket opening.

pj
chgo

The white square below, exactly 50" on each side, shows the "equal angle" geometry. Rolling kicks have to be aimed a little short (say, at the diamond on the rail) to compensate for "forward roll masse".

View attachment 525968
It's not really possible to set up in the center of the side pocket at the cushion nose line....the ball would fall in the pocket. Once you move out to where it will sit still you would want to move along the dashed shot line and not straight out.

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Maybe the real learning for me is that I have always misunderstood the table/pocket geometry? But the discrepancy is larger than this.

The shots to the right side are not coming up a fraction short, they are coming up way short though. And why then when I shoot the same shot on a mirror image the other direction the side pocket isn't short?

I will make a video showing it
Maybe your long rails weren't installed exactly parallel with each other?

But in that case you should get opposite results shooting from opposite rails...?

pj
chgo
 
It's not really possible to set up in the center of the side pocket at the cushion nose line....the ball would fall in the pocket. Once you move out to where it will sit still you would want to move along the dashed shot line and not straight out.

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Yes, and even with the ball on the cushion nose line there is also a small adjustment toward the corner pocket as I said in my edited post above (not "exactly in the center of the pocket opening" as I said in your quote).

pj
chgo
 
Without seeing your mechanics my first guess would be, that you are shooting down more on the out of the corner shot , because it's harder to bridge, and getting a bit of squirt/deflection you don't notice.
Use a striped ball, put the stripe in a line towards the spot you are aiming at, and see if it rolls end over end or is spinning or sliding.
 
I did shoot a video and I believe the problem is poor stroking with the short bridge length required on these shots.

My stroke is generally pretty straight with a normal bridge length and follow through. But was horrendous on this excercise.

It's funny how something random like this can expose major fundamental issues a person isn't even aware of.

Here is the video. It's so ugly it's hard to watch. Hard to believe I'm a 600 fargo. $10 nine ball anyone?:embarrassed2:

https://youtu.be/hV61CwL2Pfw
 
Maybe try setting up a line of dead balls rather than shooting the shot yourself? This would take unintentional english out of the equation.

If you wanted to get very precise you could setup two rows of dead balls near the side pocket. One row would be aiming at the 2nd diamond to the right and the other row would be aiming at the 2nd diamond to the left. Then you hit the cue ball into both rows simultaneously like a trick shot and see if the results are the same in both directions. This way you take out the english and speed variables.
 
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Looking at the video, it seems totally plausible that you are unintentionally applying

english. Shooting left to right comes up short, shooting with unintentional left spin.

Shooting right to left you make it. It cannot be the table. If it were, it would not work one

way, and not the other. Another thing you can try, is bringing your tip a 1/2 tip over from

'your' center, and see if it goes to the pocket. I am guessing that you are not seeing center

on the ball.
 
I quickly tried my table. If I focused on no spin it was pretty much the same shot both ways but I learned a few things.

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Looking at the video, it seems totally plausible that you are unintentionally applying

english. Shooting left to right comes up short, shooting with unintentional left spin.

Shooting right to left you make it. It cannot be the table. If it were, it would not work one

way, and not the other. Another thing you can try, is bringing your tip a 1/2 tip over from

'your' center, and see if it goes to the pocket. I am guessing that you are not seeing center

on the ball.

That's my guess too. It's actually nice to discover things like this. Not that you're doing them but that there's hope for improvement.
 
Can't see your whole stroke in the video, but it looks to me like it swerves to your left pretty consistently, which is consistent with the results.
 
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