Internal Tool 64-4893 Chamfer Mills; Cutter Head Diameter (Fractional Inch): 1/4 ; Cutter Head Diameter (Decimal Inch): 0.2500 ; End Type: Single ; Shank Diameter (Decimal Inch): 0.2500 ; Shank Diameter (Inch): 1/4 ; Shank Length (Decimal Inch): 2.36