That's pretty nice looking.Foam has a hole down the center for the shaft to sit in.
Cool, thanks for answering. I might have to build one of these. Looks great!:thumbs_upAt slow speeds it doesn't move at all. It is soft foam like whats inside a bow case. Just wedge it between the rails. I set the foam inside the rails and installed a drill bit in one of the couplers and instantly it became a horizontal boring machine, Slide the foam into the bit and presto....perfectly centered hole.
One word for ya...GOOGLE.whats an arrow crestor?