This is a clamp that attaches directly to the underside of the Mendel deposition bed when used with http://www.thingiverse.com/thing:1708 feet. Like the feet, it used No. 4 1/2" countersunk woodscrews or equivalent. The belt is clamped in place by 2 M4 nuts, M4 washers and M4x16mm machine screws.It's kinda neat in that it uses the mess caused when trying to cap a hexagonal hole as a means to entrap a nut.Get an M4x40 machine screw with washer and put it in the round end of one of the two central holes in the clamp body. Put an M4 nut on the screw and do it up very tightly. This will seat the M4 nut permanently in a wad of loose plastic deposited at the end of each hexagonal hole. Remove the screw and the nut should remain in place. Repeat with other central hole. Put washers on each of two M4x16mm screws and put them in the holes for the end portion of the clamp. Bring the two together to clamp the belt and tighten M4 screws.