This is a KBC 1.5/16 inch Taper Shank Bridge Reamer with straight flutes and a 4 morse taper shank, structural reamers use extensively in Ship and Bridge building where steel plates and shapes have punched or drilled holes that are under size and rough and where it is necessary to ream holes in assemblies to obtain proper alignment and size for accepting rivets, bolts, etc. Our part number is 5-050-075