Single twist type with single spur, cutter and side lip. Hollow center twist design for fast, continuous flow of chips. Medium-fast screw pitch. For boring creosoted poles and construction timbers and construction timbers and multiple timber applications. Heat-treated full length. Guaranteed consistent Rockwell hardness. Bores smooth clean holes for installing bolts and pins. 7/16" Hex shank fits all adjustable 1/2", 3-jaw chucks and No. 43907 bit extension. 5" shank has 1-3/4" 1/2" round and 1-3/4" of 7/16" hex. Cut off hex section and use 1/2" round shank if job requires. Adapter Shank Sizes · Sizes 11/1 6" and larger have 5/16" hex shanks. · Adapter Shank fits both hand braces or power drills. Taper square shank fits hand braces. · Cut off taper square and use in both power drills and hand braces.