40 X 12 X 1.5 Solid Carbide Insert with 15 Degree Bevel — Opposite Rotation

The IRC4012L is the opposite-rotation replacement insert for the IR401 V-groove/chamfer router bit — 40mm × 12mm × 1.5mm solid carbide with a 15-degree bevel, ground as the left-hand mirror of the standard IRC4012. The insert carries the bit’s cutting edge: when the edge dulls, swap the insert and the tool returns to spec without regrinding or sending the bit out. Solid carbide holds its edge through abrasive sheet goods and high-volume production runs. Match the insert to the bit rotation — this L version fits the opposite-rotation IR401 only; standard-rotation IR400 bits take the IRC4012. Keep a spare insert on hand to turn edge changes into a minutes-long swap instead of downtime.