I just happened across this old drawing in my file and thought it might be of interest. It's a table with a "true" banking/kicking grid on it that equally divides the area between the gutters rather than between the cushion noses. This results in a grid that doesn't line up exactly with the diamonds (except the center diamonds in each direction), but does show where "equal angles" go in real life.
For a little extra accuracy the gutter is shown 1/4" closer to the rail than a half ball's width to account for the fact that balls sink into the cushions a little before they rebound. This is a guess at the average distance balls sink into the cushion for an average range of shot speeds (if you measure the gutter on a table you'll see it's a thick line because of this variance in rail compression, and its center is closer to the rail than 1/2 ball's width), and is at least a little underestimated because it doesn't take into account the fact that balls take a curved "shortcut" when they rebound and their centers never reach the pointed apex of the rebound angle, which is even closer to the rail. If this "shortcut" was taken into account the gutter would be even closer to the rail - for a hard-hitting game like banks both the rail compression and the radius of the curved shortcut are larger so the gutter might move all the way to the rail and the grid would line up with the diamonds again.
Apparently I have too much time on my hands. Anybody need their lawn mowed?
pj
chgo
P.S. The subdivisions are 1/10 of the major divisions - 1.25 inches for a grid lined up with the diamonds and a little less for a "true" grid.
For a little extra accuracy the gutter is shown 1/4" closer to the rail than a half ball's width to account for the fact that balls sink into the cushions a little before they rebound. This is a guess at the average distance balls sink into the cushion for an average range of shot speeds (if you measure the gutter on a table you'll see it's a thick line because of this variance in rail compression, and its center is closer to the rail than 1/2 ball's width), and is at least a little underestimated because it doesn't take into account the fact that balls take a curved "shortcut" when they rebound and their centers never reach the pointed apex of the rebound angle, which is even closer to the rail. If this "shortcut" was taken into account the gutter would be even closer to the rail - for a hard-hitting game like banks both the rail compression and the radius of the curved shortcut are larger so the gutter might move all the way to the rail and the grid would line up with the diamonds again.
Apparently I have too much time on my hands. Anybody need their lawn mowed?
pj
chgo
P.S. The subdivisions are 1/10 of the major divisions - 1.25 inches for a grid lined up with the diamonds and a little less for a "true" grid.
Last edited:
