View Full Version : Best way to rifle a barrel?
December 27, 2001, 12:43 AM
Also posting in Smithy...
blackpowder pistol, as my other thread...can it be rifled on a lathe? Or is the traditional cutter necessary?
December 27, 2001, 11:41 AM
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.
December 28, 2001, 11:30 PM
I realize that there are people, especially in the blackpowder crowd, who like to build their guns from scratch, but when it comes to rifling the barrel, I'd rather see people let a barrelmaker make it for 'em. For one thing, it will be a helluva lot cheaper for the customer. Also, the tooling is not that easy to make, if you are cut rifling, the gages are expensive, and a guy can go through a lot of headache on his first go at rifling a barrel. There is a lot a guy might not consider that goes into barrelmaking if he goes in half blind. I don't doubt that people who have built their own little riflers make a good barrel, but those people are often those with a lot of money and a lot of time to waste. If it's all in fun, hell, go for it, but if you think it's cost effective, your'e kidding yourself.
December 29, 2001, 12:36 AM
They were free, in .32 cal. I want larger. Smoothbore if I have to, rifled if I can. I'll buy further ones. But I didn't want to waste them, and .32 on a 15/16" octagon was ridiculous.
January 2, 2002, 02:29 PM
Deleted, Duplicate post.
January 2, 2002, 02:34 PM
With many lathes you'll have a difficult time getting the spindle to turn slowly enough in relation to the leadscrew to produce slow twist rifling. The problem isn't gearing, the slots are cut in the quadrant in such a way as to limit the maximum lead possible.
Auxiliary equipment incorporating a worm wheel attached, usually to the front end of the spindle, a worm meshing with this worm wheel, idlers and/or change gears as necessary, and a worm wheel to mesh with the leadscrew are available for some lathes, and have occasionally been used for rifling barrels.
Perhaps this is the answer of a tool and die shop owner, but I'd think it far easier to do the job right if you were to build a rifling machine from scratch. I think that there is a picture of Brockway's rifling machine in Roberts' book the Muzzle Loading Cap Lock Rifle. This will, in my opinion, be simpler to operate well unless you are an outstanding lathe operator.
There may be a bit more information on the old style rifling machines in Dillon's Kentucky Rifle than is available in Roberts' book. Roberts used some of Dillon's photos (with permission). But I don't recall Dillon showing as much regarding sine bar type machines.
Another approach is to modify a long bedded lathe to accept a sine bar attachment. Harry Pope did this. Instead of the straight sine bar used to produce regular rifling Pope used a hardwood patterns having a complex curve to drive the follower as he almost always cut gain twist barrels. A few illustrations are in The Story of Pope's Barrels by Ray M. Smith.
Still another approach is to gear a dividing head to a horizontal mill. This is illustrated in James V. Howe's 2 volume Gunsmithing book (not Home Gunsmithing.) Roy Dunlap in his Gunsmithing book indicated that this method may be more trouble than it is worth. I don't know,I've not tried this, but I've got to believe Dunlap.
If you are well versed in electronics and programming, industrial surplus outlets sometimes have servo drives which were part of machine tools for sale. I've never seen a rifling machine constructed using one of these, but I believe a practical and accurate machine could be made using one of these units instead of a sine bar, and perhaps at less cost.
Best of luck,
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