First atempt at barrel turning. Need advice.

[T*O*F]

seldom do you hear I'd like to make a raised rib barrel before I kick the bucket.

OK, I'll bite.  I'd like to make a raised rib barrel before I die.

After watching the tape and considering all the other options, I decided I would have to follow my own course of action.  In the case of Rigby type flats, the upper and side flats are purely cosmetic.  The side flats really aren't flat.  The upper edge is visible, but the rest of it fades into the barrel.  Thus, one can inlet the barrel into a round channel without have to worry about side details.

I have a round 1-1/8" barrel blank.  I bought an 1-1/4" breech plug.  Then I bought a short section of 1-1/8" ID DOM tubing.  After cutting the flats from the tubing and shaping them, they will be soldered to the barrel and filed in to the breech plug.  I already cut the upper one out using a hacksaw and two new blades.  I'll do the other two using a whizzer wheel.  I'll have to hire someone to taper the barrel for me when I get to that point.

[coutios]

 This past June at Friendship there was a fella that had set up behind GunMakers Hall. He was hand filing the raised sighting platform on a rather large,long, tapered(swamped???) barrel. He had at it hard for a couple days with various files.. Was looking good last I saw it. If I remember correctly he said they were for a French style gun.. I think he does this work on a some what regular basis..  Sorry don't remember a name... If your interested maybe Dennis Pirdy(sp) or Dick Miller could be of some help.............

Regards
Dave

[westbj2]

When finishing a barrel with details such as a sighting rib or Rigby flats as well as a round section at the breech, I have had good success making a filing guide for the round section.
The barrel was for a cartridge gun so the barrel breech had male threads, in the case of a muzzleloading barrel one would simply need to replicate the barrel threads. 
I calculated the rate of taper on the barrel to determine the final diameter at the breech and turned a piece of mild steel to that diameter and about 3/4" long then internally threaded the 'bushing' so that I could screw it on to the barrel threads.  Used Kasenit to harden the bushing.
I roughed out the flats on the mill but there was still a good deal of material between them and around the bottom of the barrel.
With the bushing in place, it was fairly simple to file the round section (about 3" long) out of the lump of excess material.
Also, the bushing keeps the very end of the barrel crisp and sharp with out worrying about the tendency to round this corner off otherwise.
Jim Westberg

[keweenaw]

I saw Jim's job on this, it was super!

Tom

[huntinguy]

Doing that job on a conventional machine is almost impossible.

You would stand a chance if you had a taper attachment for your lathe and calculated the diameter at the proud portion and then cut to that dimension and finished the balance of the barrel in that area by scraping using the taper attachment.

IF you were better than I, you could use the set over method to cut the taper, but at that angle you would have to use ball centers instead of 60 degree centers and I think I would use them live as dead I think they would want to gall into the barrel.  False centers in the barrel are a must.

A milling cutter wouldn't work because the radius on the barrel changes as it moves up the barrel, though you could do it to save some hand filing.

I would agree with the others. The barrel was most likely forged close, reamed to proper size then hand filed and scraped in.

It would be a fairly simple job on a 3axis CNC lathe.  I have done parts like that with similar profiles that way.

[eddie]

Good morning rolf i am new to this site. if you have a milling machine and a dividing head you can duplicate that pattern with a minimum of problems. the raised portion of the barrel follows the angle of the barrel consequently if you could figure out where the relief starts on one side of the barrel and ends on the other side then you know how many degrees you have to go, by mounting the barrel between centers in the dividing head and indicateing it straight you can use an endmill to create small steps all at the same depth  along the length of the barrel that will take very little time to file out. the raised portions that are outined with something other than a straight line can be stepped in, the steps can be figured out with trigonometry. i have made mold cores useing this method and it really works it just takes time but hand work can take much longer. take care. eddie hines

[Jim Kibler]

I think some may not realize the barrel is not a straight taper, but rather a gentle curved profile.  I think it's also simplistic to just think of this as having round cross sections with applied flats for the lock, sighting rib etc.  In looking at original barrels of this type this is not necessarily the case, particularly at the breech.  I have nothing against machinging and saving time, but I'll say it one last time, a barrel such as this is going to require siginificant hand work to accomplish.