OSG 52512000 Indexable Spotting & Center Drills; Drill Diameter (Decimal Inch): 0.5310; Maximum Depth of Cut (Decimal Inch): 0.2280; Included Angle: 90; Shank Diameter (Inch): 0.625; Number of Drill Inserts: 1; Overall Length (Decimal Inch): 4.50000;