RIFLING CUTTER

In rifling barrels, a rifling head to hold the cutter is used. This is attached the rod or tube which draws the
cutter through the barrel. The rifling head is a steel cylinder, three to 6 inches in length, which will just
pass through the drilled and reamed barrel blank.

On the side a slot is cut lengthwise of the cylinder, just wide enough to accept the cutter, which fills the
slot from side to side and end to end closely enough so that it has no movement. The slot is cut nearly
through the cylinder, seating the cutter as deeply as possible.

The rifling cutter is made from a good tool steel, such as 01 tool steel. It is flat-bottomed and its cutting
edge is of the hook type, like a file tooth. The cutting edge has a rake of five to six degrees, both on the
face and on the top. The top of the cutting edge is slightly rounded which will fit the radius or diameter of
the barrel. The steel cutter is usually about 1 1/2" long and the cutting edge is slightly back of center.

This will leave a space in front of it large enough to hold the chips that are cut in one pass.

When the cutter is setting on the bottom of the slot the top of the cutting edge is just below the surface of
the rifling head. The cutter is raised to rifling position by placing very thin brass shims underneath of it in
the slot. The brass shims should be .0002" to .0003" in thickness.

After the rifling cutter makes a cut in each groove, another shim is placed beneath the cutter. Another cut
is then made in each groove until all the grooves are cut to the proper depth. A small hole is first drilled
through the rifling head on the bottom of the cutter slot so a small punch can be inserted through the hole
to remove the cutter out of the slot in the rifling head.

The rifling head is a hollow or tubular piece of high-carbon tool steel that is hardened. The hook-type
cutter is set in a port within this tube and the hook or cutting edge is about one fourth of the length of the
cutter from the rear end. The rear end of the cutter is beveled off at a thirty-degree angle on the topside
and the rear end in the rifling head is beveled at this same angle. The cutter must be beveled on each
end at the bottom from a point directly beneath the cutting edge. The bottom bevel is normally ten
degrees. At the rear of the rifling head, a beveled wedge rests beneath the beveled rear of the cutter.