These bit cut the strongest mitre joints you will use. Use 55-503 on stock from 5/8” (16 mm) to 1-1/8” (28 mm) or the smaller 55-502 for stock from 3/8” (9.5 mm) to ¾” (19 mm) thick. Build boxes, frames beams, face frame corners and other right angle joints. Maximum safe speed is 16,000 rpm.