Screws with a diameter over 1 ½ inches have a hardness rating of HRB 95 - HRC 35

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

3/4-10 x 4 1/2 Grade 8 Hex Cap Screw Yellow Zinc Plated

61/64 x 6 Reduced Shank Drill Bit (1/2 Shank)

3/4-10 x 4 Flat Socket Cap Screw Alloy

33/64 x 6 Reduced Shank Drill Bit (1/2 Shank) 5/8-11 Grade 5 Hex Cap Screws Zinc Plated Screws with a diameter over33 64 x 6 Reduced Shank Drill Bit (1 2 Shank) . Expands the size range capacity of a 1 2 inch portable drill chuck. Common flute and overall length for minimal adjustment during tool changes. Precision ground for high degree of concentricity between shank and body diameter. Ideal for drilling in low and medium tensile strength materials.