Hardness requirements of HRB 68 - HRC 32 are met or exceeded

1-8 Finished Hex Nut Silicon Bronze

47/64 x 6 Reduced Shank Drill Bit (1/2 Shank)

55/64 x 6 Reduced Shank Drill Bit (1/2 Shank)

5/8-11 Drop-In Anchor 303 SS (25)

#46 Heavy Duty Jobber Drill Bit (12) 5/8-11 Socket Cap Screws 18-8 Stainless Steel Hardness requirements of HRB 68#46 Heavy Duty Jobber Drill Bit . Web construction is heavier than general purpose construction making it particularly suitable for cotter pin hole drilling and cross hole drilling in head of bolts. The heavy construction affords efficient drilling in stainless steel and other hard materials. The split point reduces the thrust requirements and minimizes walking.