Filing a round barrel to octagon

[Camerl2009]

yep,you're right.  i misread the breech diameter.  3/8 is still possible.  There won't be much pressure with the powder charges that will be in there. 

Have you figured out yet how wide the flats will be?  They are not very big...

No and can’t really figure that out.

[Rolf]

yep,you're right.  i misread the breech diameter.  3/8 is still possible.  There won't be much pressure with the powder charges that will be in there. 

Have you figured out yet how wide the flats will be?  They are not very big...

No and can’t really figure that out.

A circle 3/8 in = 0.375in   will fit an octagon with sides 0.1435in    using this calculator  https://www.omnicalculator.com/math/octagon

Best regards
Rolf

[Camerl2009]

yep,you're right.  i misread the breech diameter.  3/8 is still possible.  There won't be much pressure with the powder charges that will be in there. 

Have you figured out yet how wide the flats will be?  They are not very big...

No and can’t really figure that out.

A circle 3/8 in = 0.375in   will fit an octagon with sides 0.1435in    using this calculator  https://www.omnicalculator.com/math/octagon

Best regards
Rolf

Barel
Is 11/16 tapering to 5/8 or so at the muzzle.

[Rolf]

11/16 in = 0,6875 in  which will give a flat 0.2631 in
5/8in = 0.625in  which will give a flat 0.2392 in

Best regards

Rolf

[Bob Roller]

11/16 in = 0,6875 in  which will give a flat 0.2631 in
5/8in = 0.625in  which will give a flat 0.2392 in

Best regards

Rolf

Rolf,
Just thinking about filing a round barrel to octagon makes me tired. did it once in the long gone past and at that time was not aware of files with aggressive cuts that would have made the job easier.It was a pistol barrel.The next one was after 1967,the year I bought a new milling machine.
Are you making progress on those locks? I doubt if I will make any more in any style and haven't been in the shop this winter unless I needed a tool.Those 4 screw locks are a work of art and you are doing a good job and myself and others wish you all the success possible with this project.
Bob Roller

[taterbug]

So, think about it this way.  You will only need to be taking about .027" material thickness (but .263 WIDE) off the big end to create each flat, and about .025" (but .239 wide) off the little end on each flat.  It's not all that much, and will go quickly at first.  The file will only make a tiny flat on the first pass, but each pass after the flat will widen very quickly.  That's when the amount of metal starts to become more effort and work. 

Your the next mission, should you choose to accept it, is to put layout lines on that barrel to file down to.  a bit tricky, but certainly not impossible.

There are ways around everything.  I'm sure machinists among us have plenty of ideas on how to do that.  I have some too, but it will require a precision measuring method, straight edges and a few feeler gauges.  If that measuring method and straight edge are one and the same, and says "Billy Bob's Used Lumber and Salvage Yard" on it, maybe think about using the barrel as is?

Kidding!  There are ways

[Camerl2009]

So, think about it this way.  You will only need to be taking about .027" material thickness (but .263 WIDE) off the big end to create each flat, and about .025" (but .239 wide) off the little end on each flat.  It's not all that much, and will go quickly at first.  The file will only make a tiny flat on the first pass, but each pass after the flat will widen very quickly.  That's when the amount of metal starts to become more effort and work. 

Your the next mission, should you choose to accept it, is to put layout lines on that barrel to file down to.  a bit tricky, but certainly not impossible.

There are ways around everything.  I'm sure machinists among us have plenty of ideas on how to do that.  I have some too, but it will require a precision measuring method, straight edges and a few feeler gauges.  If that measuring method and straight edge are one and the same, and says "Billy Bob's Used Lumber and Salvage Yard" on it, maybe think about using the barrel as is?

Kidding!  There are ways

I definitely don’t have any machinist straight edges I have been looking for some to service my cross cut saws but no luck locally.

[Camerl2009]

11/16 in = 0,6875 in  which will give a flat 0.2631 in
5/8in = 0.625in  which will give a flat 0.2392 in

Best regards

Rolf

Thank you. Breech threads would these be better off a finer thread say 3/8-24 or would the more standard 3/8-16 be fine

[Camerl2009]

This was a 7/8" round Bauska blank, about 7/8" in diameter. I decided to file flats on it and taper the rest round. only the top 5 flats are filed. The bottom of the barrel was left mostly round,
so the bore is not in the middle at the breech. It is currently .820" side to side on the breech flats and .795 at the front end of the flats, so it is slightly tapered. The breech end of the round
part is .734" and the muzzle of the 29 1/4" barrel is .660".
So, yes, you can file flats. I used an auto-body file with huge rounded teeth for the job. It takes off curls of steel. The file is now dull, but it was sharp when I started.
So, yes, you can file a barrel from round to octagonal - or with only the top 5 flats cut. I did a little at the breech as well, on the bottom to fit a TC Seneca.
Trying to remember when I did this - likely 1980 or so.

I seem to have missed this I actually have a few of those files and the holder for them as auto body is what I did for a living. Those files were mainly used in the days of real sheet metal and body solder filler but still come in handy from time to time their great for wasting away wood.

[Levy]

Please give up the thought of using modern powder in a flintlock or percussion firearm as it doesn't matter what kind of steel the barrel is made of.  It's the ignition system that can't take it even if the barrel is made of ordnance steel.  James Levy

[P.W.Berkuta]

I can think of better ways to waste my time .

[Camerl2009]

Please give up the thought of using modern powder in a flintlock or percussion firearm as it doesn't matter what kind of steel the barrel is made of.  It's the ignition system that can't take it even if the barrel is made of ordnance steel.  James Levy

Who said anything about modern powder?.

Only reference to powder so far has been by members that have built them and they reference black powder. I myself only use holy black in anything but modern(relatively anyway) off topic guns.