G8721 Drill Bushing Bushing Type Slip Fixed Renewable Combination Thin Wall SF Inside Dia 5/16 In Outside Dia 9/16 In Inside Dia Tolerance .0001-+.0005 In Outside Dia Tolerance -0.0005 - -0.0007 In Concentricity Tolerance .0005 In T.I.R. Max Overall Length 1 In Material 52100 Thru Hardened Finish Steel Drill Size 5/16 In Hardness RC 62-64