'Drill Bushing, Head Press Fit, Inside Dia. 0.098 In., Outside Dia. 1/4 In., Inside Dia. Tolerance +.0001- +.0004 In., Outside Dia. Tolerance +0.0016 - +0.0013 In., Concentricity Tolerance .0003 In. T.I.R. Max, Overall Length 1/4 In., Material 52100 Thru Hardened, Finish STEEL, Drill Size #40, Hardness RC 62-64'