Right, that's the reason. Now the point I'm presenting, if the gutter line were 2:1 (as opposed to the cushion nose), and the diamonds were 1/8th spacing of the gutter line length (rather than the cushion nose length) then everything would be geometrically the same across different table sizes. (And for carom tables the gutter line would take into account the ball size).
If by gutter lines you mean the actual line the ball sits on when touching the rail then they are already as much 2:1 ratio as anything else on the table. I'm not following you with the diamonds being 1/8 spacing of the gutter. Is this something you could use a temporary mark of some sort for testing your theory?
ah, I see. Honestly I'm not sure I could aim at the difference and hit it though.
50"×100" isn't 2:1 I always thought it wasI was drawing a table for fun in CAD and came across a couple interesting things. The dimensions of the cushions and the diamonds came from the WPA site, which is a copy of the old BCA specs, complete with typos. The picture shows a bank/kick from the corner to the side. On the right half of the table, I'm using the gutter line, which is how the ball moves in real life (disregarding rail compression). On the left side of the picture I'm using the nose of the cushion. Both are perfect mirrors. The angles are different. On the right picture, which I believe is correct, the aim point is not even perfectly across the diamond.
I believe I saw something similar to this in Wining One Pocket where they had an accurate table diagram with the diamonds. I haven't read it in 25 years though, and don't have the book handy right now. I vaguely recall the author of the book was suggesting the rail diamonds should actually be on the cloth gutter line to be accurate, rather than on the wood rail.
I think this all stems from the actual playing area that the center of the ball can "touch" is not really 2:1. This would be the gutter line. The gutter line is not 2:1.
I don't really have a point here, I just found this interesting. Maybe the question would be if tables were invented today, should they have been made with the gutter line being 2:1, rather than the cushion nose?
View attachment 720385
Here is the CAD link. You can spin it around and zoom in/out if on a computer using the mouse or keyboard arrows. It won't work as well if you open the link on mobile:
Onshape
Sign in to Onshape, the #1 fastest growing CAD system in the world with over 4 million users.cad.onshape.com
@Bob Jewett @dr_dave
The yokels think two-by-fours are 2:1 as well. Same basic problem.50"×100" isn't 2:1 I always thought it was
The tricky part is getting the feel of the table. How much does the cushion compress at each speed to rebound where and how you think it should? If you want to see somebody with feel on banks and what can be done with shots watch this:I was drawing a table for fun in CAD and came across a couple interesting things. The dimensions of the cushions and the diamonds came from the WPA site, which is a copy of the old BCA specs, complete with typos. The picture shows a bank/kick from the corner to the side. On the right half of the table, I'm using the gutter line, which is how the ball moves in real life (disregarding rail compression). On the left side of the picture I'm using the nose of the cushion. Both are perfect mirrors. The angles are different. On the right picture, which I believe is correct, the aim point is not even perfectly across the diamond.
I believe I saw something similar to this in Wining One Pocket where they had an accurate table diagram with the diamonds. I haven't read it in 25 years though, and don't have the book handy right now. I vaguely recall the author of the book was suggesting the rail diamonds should actually be on the cloth gutter line to be accurate, rather than on the wood rail.
I think this all stems from the actual playing area that the center of the ball can "touch" is not really 2:1. This would be the gutter line. The gutter line is not 2:1.
I don't really have a point here, I just found this interesting. Maybe the question would be if tables were invented today, should they have been made with the gutter line being 2:1, rather than the cushion nose?
View attachment 720385
Here is the CAD link. You can spin it around and zoom in/out if on a computer using the mouse or keyboard arrows. It won't work as well if you open the link on mobile:
Onshape
Sign in to Onshape, the #1 fastest growing CAD system in the world with over 4 million users.
@Bob Jewett @dr_dave
i dont see the why you are making a big deal about this
I think where the sights are located is brilliant. 2-to-1, rolling-ball, through-diamond systems work well on almost all tables (except Diamonds). The proportion-distortion table-size effect is probably too small to worry amount and it might be offset by the delayed curve-forward-on-rebound effect not included in your diagrams. If so, the playing-area definition is also brilliant.
So, You think the angles of return on the 3rd/4th/5th cushion will change from a 5'x10' 3C to a 4'x8' 3C table?
Yes, correct. Just to make sure we are on the same page, I am ONLY referring to the "perfect geometric angle-in = angle-out". I'm not referring to real world physics effects. The diamonds are of course placed on the table based on geometry, not real world physics.
Yes, the real world physics like the sliding/delay across the cushion are not accounted for in my diagram. But, they were also not accounted for when the diamonds were placed on the tables by the table vendors 100 or more years ago. They were based on simply dividing the table size equally.
It's their distance back from the cushion nose/gutter that makes them work for that.
Do You know what the distance is between diamonds on a 10' table/9'/8'?
