Three Rail Bank

Bob Jewett said:
That's not the way I do it. The simple mirror reflection way is almost guaranteed to find the wrong spot for nearly all shots. Instead find the following spot for the way you play the shot on your table:

Find the exact line for the bank from one position in the class of shots you are working on. (In this thread, the first class of shots is three rail banks for a ball frozen to the first cushion.) Since this is a one pocket shot, it must be played at a speed that leaves the ball by your pocket. Once you have found that line by repeated carefully aligned shots, mark it somehow. A piece of painter's tape on the wall along the line is one way.

Next, find the line for a second shot from the class of shots. For the diagram above, move the object ball to the other side of the side pocket, say two diamonds above it, on the headstring. By repeated, careful shots, find the exact line for banking such a frozen ball. Mark that line on the wall.

You now have two lines. One line is from the first object ball position to the first piece of tape on the wall. Imagine you stretch a piece of string between those two points. The second line is from the second object ball position to the second piece of tape on the wall. Stretch a second piece of string between those two points.

Those two lines will cross. With luck and for most spot-on-the-wall systems, they will cross within the room. The point where they cross is your spot. It is the single point that will give a target for the two shots you lined up so carefully. It is exact for those two shots.

That spot will also work well for all the object ball positions between the two shots you worked on and also shots outside that range. If you are really fanatic about this you can do the careful measurement for a bunch of object ball positions.

Here's a video about how to create your own spot on the wall system for whatever diamond system or bank system you want to convert.

Click to expand...
Thanks. I've been meaning to try that.

The actual mirrored pocket for the shot in the video (~red X in pic below), is pretty close to the crossed-lines (spot on the wall) target and would be even closer for non-sliding banks. As a "reference" target, do you know whether the actual mirror position for one-rail kick/banks is closer to or farther from the actual target than the actual mirror position for two- or three-rail shots?

pj
chgo

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Patrick Johnson said:
The "spot on the wall" method is based on visualizing mirror images of side-by-side tables (playing areas) and aiming at the visualized pocket that's the right number of rails away. Here's how that looks for your shot - the visualized target pocket is in the top corner of the diagram (about 12' diagonally from the far corner of your table). If your pool room's big enough you can measure the right distance and "mark" or memorize that spot for 3-railers to that pocket from anywhere.

pj
chgo

View attachment 715787
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Thanks for drawing that up. I know that the friction, spin of the ball, and other factors aren't accounted for, but drawing up banks like this helped me understand multi rail banks much better. It's useful to see it laid out even if it still needs some compensation.
 
I haven't read all the replied which have been posted and I apologize if I happen to be reiterating someone else's post but here goes.
My first thought is; Can this three rail bank run short? in other words can i cause the object ball to bank into the top rail and have the ball run three rails and directly towards my own side rail. If I find that to be unlikely then that is what I try to do. I will attempt to cause the ball to hit as close to the upper left corner as possible and let it go at that.
Attempting to use systems for shots like this are near impossible. From table to table systems must be adjusted. The fact that the object ball is tight to the rail creates another wrinkle to the equation. Too many factors to consider so take the simple approach as I stated previously.

Anyway, this reasoning has worked well for many years and I see no reason to use any complicated methods.


Tom
 
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This is my graphical method of compensating for natural roll. {Illustrated at 45º angle}

1) Starting with the CB on head spot, you aim at where the diamond would be of the center pocket
2) The natural reflection line will com up short on the long rain as illustrated.
3) the diamond reflection line goes into the pocket
4) the CB (in this case) reflects off of the rail, but the natural forward roll arcs it forward to that it intersects the pocket at the diamond reflection line.
5) sidespin alters the bank angle
6) top spin creates more arc
7) draw creates less arc (even negative)

NaturalRollBank.JPG


This illustrates why the diamonds are as far back from the nose of the cushion as they are.
This illustrates why light or heavy balls don't bank correctly
It is easy and fast to use at the table

{{Notice I added diamonds in the side and corner pockets for easier grasp.}}

About all you have to do is understand is that CB hits the rail early, and then arcs forward as if it reflected off the line at the center of the diamonds. {{When you get to the minutia, the length of the arc is dependent on the speed of the cloth, the polish on the balls, and the weight of the balls. I have drawn this length as if it were 0 length.}}
 
Tennesseejoe said:
Yes, very good comment. Do you mean frozen to the rail versus 1/4 inch off the rail?
Click to expand...
No. The two basic bank shots are when the ball is sliding without any follow at all when it hits the rail and when it is rolling smoothly on the cloth when it hits the rail. These two kind of balls take a very different angle off the first rail This knowledge is absolutely fundamental to good banking.

Of course it is possible for all kinds of partial follow/roll in between those two pure states. If the object ball is in an in between state, it becomes very hard to predict.

If the ball starts only a small distance from the rail -- or it is whacked hard from farther back -- it will have almost no follow when it gets to the cushion and so it will go very, very close to the frozen case path.
 
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Bob Jewett said:
No. The two basic bank shots are when the ball is sliding without any follow at all when it hits the rail and when it is rolling smoothly on the cloth when it hits the rail. These two kind of balls take a very different angle off the first rail This knowledge is absolutely fundamental to good banking.

Of course it is possible for all kinds of partial follow/roll in between those two pure states. If the object ball is in an in between state, it becomes very hard to predict.

If the ball starts only a small distance from the rail -- or it is whacked hard from farther back -- it will have almost no follow when it gets to the cushion and so it will go very, very close to the frozen case path.
Click to expand...
I thought maybe the pinching effect of the frozen ball may have a different effect than a ball that was just close.
It is amazing the varied information you have. I wish I could have taken lessons from you about 65 or 70 years ago. Thanks....
 
Tennesseejoe said:
I thought maybe the pinching effect of the frozen ball may have a different effect than a ball that was just close.
It is amazing the varied information you have. I wish I could have taken lessons from you about 65 or 70 years ago. Thanks....
Click to expand...
I could have shown you where the good places for crawfish and red currants were, but my pool knowledge would have been zero.
 
MitchAlsup said:
This illustrates why the diamonds are as far back from the nose of the cushion as they are.
This illustrates why light or heavy balls don't bank correctly
It is easy and fast to use at the table

{{Notice I added diamonds in the side and corner pockets for easier grasp.}}
Click to expand...
Yes, I use the diamonds the same way to aim rolling banks/kicks - pretty accurate under most conditions.

pj
chgo

P.S. I think the "diamonds" in the corner pockets should be parallel with the cushion noses (12 1/2" from the previous one).
 
Patrick Johnson said:
P.S. I think the "diamonds" in the corner pockets should be parallel with the cushion noses (12 1/2" from the previous one).
Click to expand...
I copied the distance between diamonds on the figure "Chalky stick".
Whatever error there is originated there.
And I agree with you that they look "out of place" a bit.

But I got tired looking for an accurate table figure on which to draw my conjecture.
 
MitchAlsup said:
I copied the distance between diamonds on the figure "Chalky stick".
Whatever error there is originated there.
And I agree with you that they look "out of place" a bit.

But I got tired looking for an accurate table figure on which to draw my conjecture.
Click to expand...
Here you go. I recommend the ones I made. They are more or less identical to Gold Crown measurements.

Anyone who can't get the 1/8 1/4 diamond placement right on a production table diagram ought to go back to middle school and take mechanical drawing again. Or has that been eliminated?

Templates and Diagrams - Dr. Dave Pool Info

Instructional templates and diagrams for teaching and learning pool and billiards.
billiards.colostate.edu billiards.colostate.edu

Bob <- took mechanical drawing in middle school in both Lake Charles and Berkeley
 
Bob Jewett said:
Anyone who can't get the 1/8 1/4 diamond placement right on a production table diagram ought to go back to middle school and take mechanical drawing again.
Click to expand...

What I did was to duplicate the size of the round diamond
then I measured the distance in my draw tool and found the center to left and center to right were very close.
Then I duplicated 2 new diamonds and placed them equidistant from the 3 on the rail.

And thanks for the links--any future drawing will be done from on of the more accurate ones.
 
MitchAlsup said:
I copied the distance between diamonds on the figure "Chalky stick".
Whatever error there is originated there.
And I agree with you that they look "out of place" a bit.

But I got tired looking for an accurate table figure on which to draw my conjecture.
Click to expand...
Yeah, those diamonds are evenly spaced, but slightly too far apart for the table (that foot string must also be off a little). The corner spots should be where the red ones are below (at the edges of the playing area).

Blank (1).png

Your shot diagram still makes sense - sorry for the interruption. But maybe ChalkySticks should check their dimensions (particularly the locations of the spots).

pj
chgo
 
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Patrick Johnson said:
Thanks. I've been meaning to try that.

The actual mirrored pocket for the shot in the video (~red X in pic below), is pretty close to the crossed-lines (spot on the wall) target and would be even closer for non-sliding banks. As a "reference" target, do you know whether the actual mirror position for one-rail kick/banks is closer to or farther from the actual target than the actual mirror position for two- or three-rail shots?

pj
chgo

View attachment 715900
Click to expand...
since sliding banks do react like rolling banks it does not surprise me that the "mirror pocket"red X does not match the spot on the wall for sliding banks
this assumes mirror pockets are for rolling balls ........is that correct?
 
Bob Jewett said:
No. The two basic bank shots are when the ball is sliding without any follow at all when it hits the rail and when it is rolling smoothly on the cloth when it hits the rail. These two kind of balls take a very different angle off the first rail This knowledge is absolutely fundamental to good banking.

Of course it is possible for all kinds of partial follow/roll in between those two pure states. If the object ball is in an in between state, it becomes very hard to predict.

If the ball starts only a small distance from the rail -- or it is whacked hard from farther back -- it will have almost no follow when it gets to the cushion and so it will go very, very close to the frozen case path.
Click to expand...
Bob are you saying the bank rolls longer if the frozen ball path is not in play?
 
atlas333 said:
Bob are you saying the bank rolls longer if the frozen ball path is not in play?
Click to expand...
I think so but the way you say it is not perfectly clear to me.

A ball that slides into the cushion without any spin at all on it comes off the cushion shorter (less parallel to the cushion) than a ball that rolls into a cushion with smooth rolling on the cloth with no slipping. Between those two, if a ball is partly rolling when it hits the cushion, it will come off between the totally sliding and totally rolling path.
 
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