The bits I wanted to use were out of specification. The shank size should have been 1/4 inch. The 3/8" semi-circular shaft was 2/16" oversized, making installation and removal difficult. The 3/4" round shank was 3/16" undersized and not hardened. It flew out of the turntable and smashed my work light and safety cover right after I tightened it and started it. Do not buy these items.