HHIP 3/4 INCH C6 12 PIECE BORING BAR SET (1001-0004) A Shank Dia. (In) 3/4 | Set PC. 12 Shanks are made of special heat treated alloy steel. | Three lengths for each minimum bore size. Quality tool designed to be used as a boring tool bit. All shanks are held to 0.000 - 0.0005" from the nominal size. Grade C-6 for all types of steel and general purpose.