Union Butterfield 47031.3/8 taper shank counterbore, 1-3/8 inch cutting diameter, 5 flutes. Part number 6210093. For enlarging and spotfacing holes to precise depths in machining applications.

Interchangeable pilot-counterbore body with 5-flutes, diameter 1.3/8" with an overall length of 6.5/8" and a flute length of 2" and MT 3 Morse-taper shank, according to ANSI standard to produce a flat bottom seat for socket-head cap screws with the aid of a pilot with a shank diameter of 3/8" and a maximum pilot guide diameter of 1.5/16", HSS with standard bright finish for machining free machining and plain carbon steel, wrought and copper or copper alloys.