Reply by pintodeluxe

I wrap strips of mdf around my router plate to make a rectangle. Screw them together with pocket screws. Make two sides of the rectangle extra long to allow for clamping. Then you can rout the ledge. Finally remove the center portion with the router or jigsaw.

I place two layers of masking tape around the router plate before building the mdf template. That way the recess won’t be too tight.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush