10-17-2010, 03:46 PM
For me, there is 1/4 inch of roadbed, 2 inches of foam, and 1/4 inch of plywood for a total thickness of 2.5 inches. A 3 inch long bit barely chucked up in the drill is long enough for me to drill a pilot hole from the top. With my mechanisms and the long spring steel wire, there is plenty of tolerance for error. The hole on the bottom is somewhat oversized, and the controller can be moved around for best operation, then screwed there.
With a double thickness of 2 inch foam like Randy has, instead of hunting for an extra long drill bit, you could take a stiff piece of wire, perhaps from a wire coathanger, cut it off at an angle with wire cutters, and use that as a drill bit. The 1/4" plywood is pretty easy to drill through (don't push down to hard, let the angled wire do the cutting, otherwise you may bend the wire). I used the coathange drill bit technique myself in a couple places where my feeder wires needed an angled hole so as to miss cross braces and such.
With a double thickness of 2 inch foam like Randy has, instead of hunting for an extra long drill bit, you could take a stiff piece of wire, perhaps from a wire coathanger, cut it off at an angle with wire cutters, and use that as a drill bit. The 1/4" plywood is pretty easy to drill through (don't push down to hard, let the angled wire do the cutting, otherwise you may bend the wire). I used the coathange drill bit technique myself in a couple places where my feeder wires needed an angled hole so as to miss cross braces and such.
Three Foot Rule In Effect At All Times