Like Roy, I've used mild steel. One trick I found that works well is to cut the filler piece over-sized, too long and too high. Install the piece and then CAREFULLY peen the ends, backing it up against the flat part of a vise or some other solid, flat suface. Give the top of the piece a few short, fast raps with the round end of a ball-peen hammer. Doing this will swell out the piece slightly to fill the dovetail and lock it in place. Then just file off smooth. P.S. This is my first post on this site. Hi everyone.
