[4V50 Gary]

While a lathe is certainly steady, you'll have to remove or modify a tailstock. The barrel must remain absolutely stationary while the cutting bit is pushed through.

Traditional rifling machines featured a large cylinder with spiral grooves cut on its exterior. The cutting bit was mounted on a long wood rod which was affixed to the center of the cylinder. Said grooves of the cylinder were guided by "pegs" in the blocks which held it to the rifling machine. As the cylinder was pushed forward, the pegs, which were in constant contact with the grooves, would cause the cylinder the turn. Depending on the frequency of the grooves of the cylinder, this would cause the bit to cut faster or slower twists in the barrel.

There are several books on how to build your own rifling machine. I don't have them in front of me, but if you can get your hands on Ned Robert's The Muzzle Loading Cap Lock Rifle, Mr. Robert has a better description of how the rifling machine works. If you can get to Friendship, Indiana, the more advanced Brockway rifling machine which operates on the sine bar can be seen. You may be able to convince the curator to operate it for you. They let a bunch of us have a tug and pull on it to make a barrel that was raffled off earlier this year.