Ideal for CNC stem system & dadoes 1/5.1 cm spoilboard surfacing and rabbedding bit cutter. 1-1/2" diameter. 1/2" shank. The ideal bit spoilboard perfectly flat for maintaining the highest accuracy in your projects, this bit is also ideal for routing precise rabbets. The replaceable solid carbide inserts can be rotated, so that all four corners are used, extremely long service life, even in abrasive materials.