Shank Type: Taper Shank Taper Size: CAT50 Pilot Diameter (Inch): 1-1/4 Pilot Diameter (Decimal Inch): 1.2500 Projection Flange to Nose End (Decimal Inch): 3.5000 Through Coolant: Yes Nose Diameter (Decimal Inch): 2.7500 Balanced to (RPM): 30000 Shell Mill Cutting Diameter Range (Inch): 3 – 3-1/2 TIR (Decimal Inch): 0.0002 Coolant Type: Through-Spindle Lock Screw Thread Size: 5/8-18