Just realized I spent 12 years cutting dados the hard way before a guy in Cleveland showed me a $30 trick
For my first 12 years in the shop I measured every dado with a tape and a square, then crept up on the fit with a chisel, and it ate almost an hour on every cabinet. Last month an old timer in Cleveland showed me how to sneak up on the width with a scrap and a feeler gauge instead, and my fit got dead on in about 4 minutes. How do you all set your dado width when the plywood is undersized?
Tape and square is fine for the first cut but it's the sneaking up that saves you, so that Cleveland guy was not wrong. Scrap and feeler gauge works but honestly a lot of us just cut a test dado in the same offcut and dial the bit by feel. Undersized ply is the real pain, some sheets run 23/32 and some run 11/16, so I keep a stack of shims cut from a soda can for the loose ones. Four minutes instead of an hour is the whole ballgame.