Onsrud HSS Spiral Upcut Router Bit, 3/8" Diameter, 1-1/4" Cutting Length, 3-3/4" OL, 1/2 Shank,Onsrud Cutter" /> Spiral design pulls waste from the cut Leaves a flat bottomed mortise Permits accurate cuts without chatter in any wood Machined from solid high speed steel 3/8" D x 1-1/4" CL x 1/2" SH