Erie Tools 11 Piece 5/16" Metal Lathe Cutter Set with Carbide Tipped for Turning, Boring, and Chamfering HSS Steel 11 piece carbide-tipped tool bit set 5/16" Shank size 2 pieces - 4-7/8" long Cranked Boring Bars 9 pieces - 3-1/4" long Bit Variety Suitable for machining mild steel brass copper and plastics For metal lathe, mini lathe, milling other general machining operations such as turning & boring