I made this coping sled some time back. I built a bunch of bookcase cabinets for my basement I while back and did not care for the clamping miter gauge setup I used to do the frames. I built this knowing someday I wood do some more. I used an old router table insert that was collecting dust after upgrading to a lift. I want something flat, thin and ridged and this fit the bill. I used oak scraps which were screwed into hole tapped in the plate. It does not ride in the miter slot but instead on the plastic safety guard at the top of the pictures. I rounded the corners of the plastic and it rides very smoothly on the router table fence. There are two HF clamps. The left one holds the workpiece down. The right one is screwed to a block which slides left and right to accommodate different widths. The right clamp holds down a backer board to avoid blowout. It makes it very easy to change backer boards otherwise I might get lazy and not throw a new scrap in there. I even used a little label maker to attach a label that says "Remember to use Backer!". I glued some sandpaper to the top of the aluminum plate to keep everything in place once tightened down. I used it tonight making some rail and panel? drawer fronts and it worked like a charm.