G2848 Drill Bushing Bushing Type Head Press Fit H Inside Dia 6.3mm Outside Dia 7/16 In Inside Dia Tolerance +.0001- +.0004 In Outside Dia Tolerance +0.0017 - +0.0014 In Concentricity Tolerance .0003 In T.I.R. Max Overall Length 1/4 In Material 52100 Thru Hardened Finish STEEL Drill Size 6.3mm Hardness RC 62-64