Accurately bore holes or refinish holes with your mill. The set includes a 2” boring head and a nine-piece carbide-tipped boring bar set. It features three mounting configurations for the 1/2" shank cutting tools to allow you to bore holes from 3/8" - 5"+ in diameter. Some larger diameters will require shaping the carbide cutters and there are some practical limitations. When the cutter is mounted horizontally, the boring head will contact the bottom of a blind hole before the cutter. The head is adjustable in 0.001" increments and has a direct read dial for greater accuracy. The part number for the head only is 47-705. The C6 carbide cutters are brazed on 1/2" shanks with a variety of chip sizes: a minimum hole range is 0.46" - 0.710" depending on the cutter. Maximum hole diameter will vary, again depending on the cutter, how it is positioned in the boring head, and type of hole being cut. The length of the cutters are from 2.250" - 4.570" in length and can vary slightly. The 9-pc set can be ordered separately, part number 47-700. The adapter mount for the boring head is 7/8"-20. Please select the right size shank for the machine. MT3 millheads require shank number 47-720, sold separately. R-8 millheads require shank 47-725, sold separately.