These groove bits are specifically designed to rou grooves and dadoes for joints in plywood. This means they match the true thickness of the material, producing tight, accurate joints. Use our 18,2mm (23/32") bit for 19mm plywood, 12,3mm (31/64") bit for 12,7mm (1/2") plywood and our 6mm for 6,35mm (1/4") plywood. No gaps. No sloppy joints. No worries! These money-saving 3-bit sets are available with 12,7mm (1/2") or 6,35 (1/4") shanks.