bolted to the side of the head stock.
At the head or gear end of the lathe, a gear is mounted on this shaft so that it meshes with the gear train
leading from the lathe spindle to the quick-change gear box. This gear may have to be a special gear, if
the gears on your lathe do not happen to be standard gears, which can be purchased from some gear
manufacture.
You might have to use two gears at this point to reach the lathe gear train. The ratio of these gears, and
of the worm and worm gear, must be figured out for your particular lathe. This is necessary to bring the
spiral produced within reach of the gear box gears of the lathe. By doing this all the common twists in
rifling may be reached by simply shifting the gears,
When you use it, the belt pulleys of the lathe are disconnected from the spindle so that the spindle turns
freely and the drive is applied at the tail end of the lead screw of the lathe.
A hand crank may be applied to the end of the lead screw and after the half-nuts of the lathe carriage
are closed upon the lead screw, the carriage is moved as the lead screw is turned. The lead screw in
turning operates the gears at the head of the lathe and through the special shafts added, which turns the
spindle with the worm and worm gear.
A pulley may be placed upon the end of the lead screw and an electric motor used to drive the lead
screw. Use V pulleys and V-belts at this point will make the best drive. A good supply of cutting oil is
supplied under pressure to the barrel being rifled. You need the oil to lengthen the life of the rifling cutter,
to make a smoother cut and to keep the barrel clean of chips.
When you cut the grooves, they should not be deeper than is necessary to grip the bullet well. To deep
grooves lead to rapid throat erosion and will sometimes put fins upon the base of bullets.