Lsing a ball cutter with a bit brace to round out, or crown, the muzzle of a rifle barrel. The special ball shaped cutter is of tungsten steel and turned at low !>pced.
cutting edge is level with the groove in the babbitt casting. This is ascertained by placing a thin steel scale edgewise into the groove over the cutter. A cut is now made over each land in the barrel, with no shim beneath the cutter and after each cut is made a very stiff bronze brush of the Parker type is used to scour any burr out of the barrel. After each land has been passed over by the cutter, a .001" shim of cellophane is placed beneath the cutter and the first land is given a cut, after which the bronze brush is used and the same land is again run over by the cutter and the bronze brush again used, this being repeated until the cutter no longer cuts on this first land. The second land is then cut in the same way, with the same number of cuts, then the balance of the lands arc cut, which should increase the bore diameter of the barrel to a diameter of .302". This may be measured by pushing a soft-lead slug through the bore, as was done to measure the groove diameter. As the ribs raised by the grooves in the barrel upon the lead slug prevent taking a measurement of the grooves made in the lead slug by the lands of the barrel unless these ribs on the slug are cut away with a knife a simple way to take this measurement is to lay two pieces of drill rod of small size in the grooves of the slug, one in one groove and the other in the opposite groove, and measure over these with a micrometer, after which the diameter of the drill rod is taken with the micrometer and the diameter of both pieces deducted from the first measurement.
As the smoothness of the cuts we have made in the grooves and upon the lands of the barrel depend upon how well the cutter is dressed and honed, this cutting edge must be watched closely and will need to be honed with a hard Arkansas stone quite often. A good magnifying glass is used to examine the edge, which should have a mirror-like finish. As our shims have been .001" thick, which is too thick for the smoothest work, the interior of the recut barrel will not be as smooth as we should like to have it so, as the barrel is still tight we can lap it with a lead lap and very fine emery powder mixed with oil.
A regular lapping rod with ball-bearing handle is used for this work. The simplest way to make it is to get a bicycle pedal of the ball-bearing type and make a short nipple, drilled and tapped in one end to screw onto the threaded end of the pedal spindle. The bicycle shop can do the threading for you if you have no
Was this article helpful?
There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.