Lathe question

Well, the octagon blank could easily be tapered & turned round like that.
As well as adding the concentric rings around the muzzle and in front of the octagon part.

You would need to grind a lathe bit to a small rounded tip to cut the bottoms of the rings.
And probably some judicious use of a tri-cornered file to round & smooth them before final polishing.

But the other stuff, zigzag lines and such, is engraving, and can't be done on a lathe.

rc

You're not gonna start with an octagon blank and turn the half round part. You start with a round blank and use a mill with a dividing head to make the flats for the octagon part.

Sorry Tuner, I disagree with you. Start with octagon blank and turn round where wanted. The round might be a little smaller than in the picture, but much easier to do.
CraigC, buy some good tool steel blanks such as Rex aaa and grind away. Just be sure to leave some rake and relief so it doesn't dig in. Needless to say, play on some scrap round stock before tackling the barrel. If you don't have any luck grinding the radius tool, cut grooves with a parting tool and round over with a small file as rc said.

you'll also need a four jaw chuck or a collet with the octagon form in it to hold on to the blank: a three jaw chuck or an round collet won't hold on to an octagon.

The firts couple cuts where you're knocking the corners off will sound awful!

Sorry Tuner, I disagree with you. Start with octagon blank and turn round where wanted.

Click to expand...

You're partly right. I defaulted to a project that my mentor gave me many years ago in which I had to start with round stock and make a half octagon "barrel" the old-fashioned way...which included draw filing the flats before he let me do it on the mill.

It took three attempts before I got it right.

One of those "Patience, Grasshopper. Patience." lessons.

Then he handed me one to make half octagon for the whole length.

Them wuz the days.

But...Starting with octagon stock, you're faced with the problem of getting the sides of the round part flush with the flats. That's the trick...unless you want them not to be flush. If you do, you're still gonna need the dividing head to bring the flats down to match the round.

Or...if you made your bones under my slave master...a file.

A properly sized 12 point socket will hold the end of octagonal stock in a 3 jaw chuck.

I would not try turning hex stock in a socket you will get all kinds of play as you would be holding the socket not the stock, they make collets for a reason.

You can turn a couple of brass plugs to fit both ends and mount it in the lathe between centers with a face plate and lathe dog if you don't have a four jaw check. Even if you do you will still want to support the opposite end with a center.

Do yourself a favor and buy some highspeed steel blanks and grind some forming tools for the bands. Careful filing and abrasive strips will clean everything up nicely when finished. You could cut the octagon portion either before or after, it wouldn't matter, but I would do it before if you aren't starting with an octagon blank to begin with. Odds are good that that barrel has some taper in it.

Also, I would just start with a stock blank rather than a pre carve if you are going to make that barrel. Mike Miller has a nice video on flintlock pistol making which would be helpful if you haven't done one before.