Schmidt Single Tongue & Groove Lock-Mitre Insert Cutter Set — 4-3/4″ × 1-1/4″ Bore

The Schmidt ID20135 is a dedicated insert lock-mitre cutter set that mills single tongue-and-groove lock-mitre corner joints. Built on a 4-3/4″ diameter, 1-1/4″ bore body carrying three carbide inserts, it cuts the precise mating faces a lock-mitre corner needs in hardwood, plywood, chipboard, and other glue-bonded or highly abrasive materials — where tungsten-carbide tooling is the right call. The set comes with inserts; replacement inserts (IC20135) restore an accurate fit and consistent cutting diameter every time instead of regrinding. Cut all panels with Part 1; Part 2 is formed from one half of the Part-1 panels (or use a 1/4″ groover such as the IG660 adjustable insert groover). Can be custom ordered in different diameters and opposite rotations.