Just designed two jobs with frames added to the backs of other frames as depth extenders. We're planning to rip the rabbets off the back frames somehow, then either glue or screw those on the backs of the front ones, so both the outside and inside walls are even. I'm planning to strip out the inside of the resulting frame, with mat or foam core that's flush to the sides. When he's tried using the jointer to rip down overly wide fillet backs to use as frame liners, the finishes wore the knives out way too fast. He's concerned with the finish on one of these frames doing the same. It's a Studio matte black, but it's got that clayish whatever that the black is made of. He's thought about running the moulding through the router, making a cut that goes most of the way through the lip, then chiseling the rest off by hand. But that seems kind of labor intensive. He just thought of putting a drum sander on the drill press with a fence and taking it off that way. Have you ever done this, and if so, how?