Milling octagon flats?

[Scota4570]

I trashed a scrap barrel trying to do this without a dividing head.  I have a medium sided vertical milling machine.  I thought I could get by with a machinist square and some V-blocks.  It was to be a 20 ga pistol barrel.  I would not try to do a rifle barrel this way.   

Plan B.  When I get the itch to try again.  Cut the breech plug threads in the round barrel.  Cut matching threads in a piece of old octagon barrel stock.  Use all thread to join the two piece.  Use the octagon barrel stub as my guide to cut the round one.  I would shim to the mill table for taper in the new octagon barrel.  I want to go 1/2 octagon and about 12" long so the octagon flats will be relatively short. 

Comments? 

[FDR]

You can also use a "hex nut" locked onto a shaft screwed into the breach plug hole.  Level each flat with a "good" precision level or do what I did a buy an indexing head. A "good enough" Chinese one is less than $100.  Check ENCO.

[okieboy]

 How would you mill an octagon barrel using a hexagon nut?

[P.W.Berkuta]

How would you mill an octagon barrel using a hexagon nut?

AH -- it is one of those machinist "Black Magic Tricks" that was taught at Hogwarts school of machinery - don't ya know .

[Scota4570]

Well actually the idea might have some merit.  Not for hexagon but for dodecagon (12 sided).  A half dodecagon half round with a couple of bands in the middle might be an interesting conversation piece.  One would have to reset the bolt/guide once to get he rest of the flats. 

[James Wilson Everett]

It would probably be quicker & simpler to use a coarse file.

Jim

[shortbarrel]

There was a fellow in Cuba that made a barrel from hex bar stock. The article was in Muzzle Blast many years ago. Think the  article was named (Is Possible In Cuba). Might look kind of cute to have the points and wood meet in the middle. I scribe eight lines breech to muzzle around the round barrel, then file. Straight, tapered or swamped.

[Shovelbuck]

Well actually the idea might have some merit.  Not for hexagon but for dodecagon (12 sided).  A half dodecagon half round with a couple of bands in the middle might be an interesting conversation piece.  One would have to reset the bolt/guide once to get he rest of the flats. 

My underslammer bench gun is 12 to round.

[jerrywh]

 I use an Enco indexing head and a adjustable tail stock.  I recommend it highly. If you do three or four you can recoup the cost by selling the others.

[Daryl]

Well actually the idea might have some merit.  Not for hexagon but for dodecagon (12 sided).  A half dodecagon half round with a couple of bands in the middle might be an interesting conversation piece.  One would have to reset the bolt/guide once to get he rest of the flats. 

My underslammer bench gun is 12 to round.

12 to the pound would be more fun!

[Bob Roller]

Round barrel?? Mill it square,use a V block in the mills vise and whack off the round corners.
Doesn't get much simpler.

Bob Roller

[FDR]

You can also use a "hex nut" locked onto a shaft screwed into the breach plug hole.  Level each flat with a "good" precision level or do what I did a buy an indexing head. A "good enough" Chinese one is less than $100.  Check ENCO.

Should have said "octagon" nut. Have to make it!  Wish I could get my fingers to type exactly what my brain is thinking! It's and age thing!

[Rolf]

This shows how I did it.
http://americanlongrifles.org/forum/index.php?topic=26376.0

Best regards
Rolf

[kaintuck]

Round barrel?? Mill it square,use a V block in the mills vise and whack off the round corners.
Doesn't get much simpler.

Bob Roller

Bob, this is 2015, things are more difficult, I pads, computers, automatic transmissions, GPS talking direction finders for hunters...ahahahahahahahahahahaaaaaa..........
Amazing how the wright brothers made airplanes........
Tomtom said this.......

[Bob Roller]

Round barrel?? Mill it square,use a V block in the mills vise and whack off the round corners.
Doesn't get much simpler.

Bob Roller

Kaintuck,
I wouldn't know what to do with an iPad but do like vintage aircraft of all kinds and am
a firm advocate of the KISS principle (KeepItSimpleStupid) and the barrel reshaping method is
a prime example.
Everyone knows of my life long affair with the Duesenberg Model "J" and I have wondered from
time to time if Fred and August Duesenberg had gone beyond the 8th grade if they could have
made a better car. The "J" was all Fred with a blank check from E.L.Cord. My respects and regards to
Tomtom.

Bob Roller


Bob, this is 2015, things are more difficult, I pads, computers, automatic transmissions, GPS talking direction finders for hunters...ahahahahahahahahahahaaaaaa..........
Amazing how the wright brothers made airplanes........
Tomtom said this.......

[P.W.Berkuta]

It would probably be quicker & simpler to use a coarse file.

Jim

OR -- just buy one -- your time & effort vs money For me I'd spend the money. When I was full of "Pi%% and Vinegar" I did the swamped barrel routine with a file then a milling machine. I come to realize that the barrel maker makes a very nice swamped barrel for a very reasonable price and I don't have to stress my heart out.

[Scota4570]

Nice job Rolf,

Your method is probably more authentic that what I had in mind. 

For lathe owners, if you off set the tailstock and turn between centers you can make a smooth taper.  The stepping down method will never come out smooth and true.  Also the wedding band can be done with a form tool.  The square plug idea is basically what I had in mind with the octagon plug.  IF you use a V-block you could use the square plug to get octagon.  Nice input guys. 

I'll probably try again.  Shotgun barrels are very cheap. 

Someone mentioned a 12-bore.  I had one once.  The velocity was very low.  Balls bounced off wood targets.  If the powder charge was enough to get penetration then recoil got uncomfortable.

I like the idea of a 20 ga guage.  I have an Ithica m-37 featherweight barrel but, it looks too lightweight to be useable.  How thin can we go and be safe?