I'm building a chassis with whose four sides are made of alum and whose top and bottom plates (covers) are made of wood. what I want to do is to
secure the top and bottom plates in place by using a threaded bolt that goes through the alum box sides (right and left) and gets screwed into the top plate (so that the hardware from the top is blind). I'm a little worried about the wood "holding" the threads and not stripping out.

Is there a metal slug or threaded insert that we could drive into the top cover (on the inside) and that would be threaded say for a 4-40 or 6-32 threaded stock?

any other ideas?

cheers,

msl