The lathe should have a large hollow spindle, so the barrel can be passed through the spindle and held
with the regular barrel chucks mounted on each end of the spindle. The oil tube, which is attached to the
rifling head, can be held in a clamp fixture mounted upon the tool rest of the lathe.
This is the best method for rifling barrels and requires the least fixtures. If the spindle of the lathe is too
small to allow the barrel to pass through it, the rifling head may be driven by the lathe spindle. The barrel
can be held in a clamp fixture mounted upon the tool rest. The clamp fixture holding the barrel should be
long and heavy, so that it may grip the barrel at two rather widely separated points.
If you use this method, you need a longer lathe bed than the first method. The bed must be long enough
to accommodate the barrel length, and it must also have sufficient length for the rifling head with enough
length of tube or pull rod on the rifling head so that it can pass clear through the barrel.
Lower priced lathes are not supplied with spiral attachments by their manufacturers. These spiral
attachments usually include an indexing attachment. If it does not have the spiral attachment, a simple
one may had in the barrel with the spindle locked in the correct position each time. An accurate
protractor mounted on the spindle nose will help you align the barrel.
A spiral attachment may be built for screw cutting engine lathe of the quick-change gear-type. The
barrels may be rifled upon the lathe, driving it either by power or by hand. To make this spiral
attachment, obtain a stock worm gear and worm, the gear being large enough so that it may be bored
out to slip over the lathe spindle nose with a close fit.
The gear is held in place with a barrel chuck screwed tightly up against it. A bracket is now made to fit
the lathe bed, as a center rest does, and on the upper part of this bracket. This can be clamped to the
lathe bed with the clamp plate used with the center rest. A shaft is then mounted, at right angles to the
centerline of the lathe.
The shaft the worm that mates the worm gear on the spindle nose is mounted so that it meshes with the
worm gear.
This worm shaft is long enough so that it extends to the front of the lathe, and a little past the head stock.
On this outer end of the shaft, a standard miter or level gear is mounted and a second miter or bevel
gear meshes with this and is on a shaft extending to the head end of the lathe. A bracket for this shaft is