Boxer
The slot is made so you can replace the sub base with other types, like a 45deg.,15deg.,etc. just remove the wings nuts and the 1/4-20 x 2" carr. bolts and put the new one in place.
Note**I grind the head down on the carr.bolt to 3/8" dia. and 3/16" high and run two slots one for the head and one for the screw, this way I full control of the sub.base.
This can be done quick and easy with a drill and a grinder.
Note **when you cut the 22 1/2 deg. put the cut off back on (glue it in place) then cut to the right size this will help support the part when you run the slot.
Bj
