Barrel swamping of old

[jerrywh]

 I have often heard  different ideas of how barrels were flared or swamped in the old days. Some say they were forged that way but forging is very inaccurate and leaves a ruff finish at best. This is how I believe it was done in most cases for many hundreds of years. This is a engraving of a gun shop around 1600.  It appears as though this barrel may be ground straight however  I have seen other engravings that show the barrel fixture set on a curved ramp in order to create a flared barrel. The barrel fixture slides back and forth on the grinding table and if the table is ramped the barrel will be ground swamped as we say now days.
 Notice that there seems to be some sort of adjustment on each end of the table. This could be to allow for tapering

[Acer Saccharum]

Jerry, it's an interesting question. It was impossible to weld a barrel perfectly straight, so it would have to go thru a straightening process. Once the bore was straight, then it could be ground on centers as your illustration above shows.

I believe in the Steinschloss book, it mentions water powered barrel grinding. I will look that up.
In the image below, the flats look ground with a very coarse wheel, with the wheel grinding across the flats, not parallel. I believe the barrel pictured is of European mfr, Belgian or German, to American specs, ie: .54 cal, x 43" long.




off topic Gunshop engraving:

[JCKelly]

Black powder pressures go up  very quickly at the breech, then drop through the rest of the barrel.

One does need more metal at the breech to withstand the explosion, then rather less further on. Since it was hand-forged one could have the barrel anyway one wanted.
That is why good ol' damascus shotgun barrels are so heavy at the breech.

Being really picky, the muzzle should be a bit thicker for strength (yes, I know pressures are lower, but this is a design/stress calculation thing. See your local PhD Mech Engr). One sees this in bronze cannon. It is not just for style.

then some of the swamping was either for style or the shooter's idea of balance. My one Kentucky Kentucky is rather heavy at the muzzle. I think this was a Southern style, what say yes friends of the Cross of St Andrew's?

I dare say they were octagonal at all as it makes more sense to forge a square, then the corners, to make an octagon rather than attempt to forge a round. Recall speaking with an older gentleman about 1968, worked for Allegheny Ludlum Leechburg, Pennsylvania plant. At that plant he used to forge octagonal barrels for Winchester, on a steam hammer.

[Bob Roller]

Acer,
I was told by one of the German International Team members that some of this barrel shaping from round to octagon was done with BIG crosscut files with a man on each end.I don't think those are grinder marks on that barrel but may be file marks.Sixty years ago,when I was eighteen I filed a twelve in round barrel into a nice octagon but now NO WAY!! My old friend Marshal Ralph Hooker filed a forty eight inch round barrel to octagon because he couldn't afford to have a machine shop do it and was afraid they'd wreck it if they did try it.

Bob Roller

[Acer Saccharum]

Bob, I can see that happening.

[rich pierce]

That barrel from Doc's gun could have been hot rasped too (rasped while red hot out of to forge).  It's rough on a rasp but takes the bark off in a hurry.  I don't know grinding stones that are that coarse.  They would almost have to be coarse abrasive embedded in a matrix to grind that coarsely.

[Acer Saccharum]

Boring in the foreground, with apprentice turning the wheel. And what appears to be a worker rifling in the background.

[Bob Roller]

I have seen and used grinding wheels that are called snagging wheels and they are brutal in their removal of material.I don't know if they are still available or not.

Bob Roller

[Bible Totin Gun Slinger]

I read a book years ago I strongly recommend to Long Arm lovers.
Foxfire 5

It covers semi primitive gun making. And other very interesting things.

[James Wilson Everett]

Guys,

In forging a wrought iron barrel, or anything out of wrought iron for that matter, when the smith strikes the metal at a free end there is a significant risk of the metal splitting along a metal grain/slag string interface.  I call this a broomstraw split.  When I forge wrought iron parts and do not get a broomstraw split - it is a minor miracle.  It is my supposition, based only on my personal experience, that a major reason for the muzzle flare is the smith wishing to avoid the broomstraw split that could result from forging at the muzzle end.  Actually when I forge a barrel I end up cutting off some inches from both the breech and muzzle ends to get sound metal.

Not a barrel, but here is an example of a cock showing both the as forged and finished forms of the same piece.  Notice on the rough forging that there is a weld repair made at the right side where I had a too big broomstraw split.  I repaired it with oxy acetelyne (don't tell nobody).  Everything I do seems to end up with at least one oops! 



Anyway, that is my two cents about a reason that may help to explain the swamp shape.

jim

[smart dog]

Hi,
This is a great thread.  Espingarda Perfeyta: The Perfect Gun, describes in detail how the Spanish and Portuguese made arguably the finest barrels in the world during the 17th and early 18th centuries.  With regard to shaping, the authors, who were 3 brothers, clearly describe octagonal flats being hammered to shape during the forging process.  Round sections were cut using firmer chisels on a lathe.  The tapering and swamping was accomplished both during the forging and later either on the lathe or by filing the flats on the octagon sections (remember, "Spanish form" barrels are what we call octagon-round).  Barrels were finished with files and emery (some sort of polishing powder) and oil.  The Spanish and Portuguese forged barrels in 5 sections, two of which were octagon and the rest round.  After forging each section, they were welded together.  According to Isidro Soler, a typical Spanish long gun barrel weighing about 6 lbs, began as 50 lbs of iron divided as follows: 14 lbs for the breech section, 10lbs for the rest of the octagon section, and three 8lbs lots for the round sections.  Clearly, the tapering and swamping was taken into considration from the very beginning of the forging process.

dave  

[mikeyfirelock]

There was a very interesting article in "Rifle" magazine years ago on this very topic.  I seem to recall that John Bivins was the author.  The conclusion was that at least some barrels were ground octagon using a parallelogram sort of frame in connection with a large water powered wheel, which produced the swamped profile.   I'll have to see if I can find the article, but it's been fully 30 or so years ago.
Mikeyfirelock

[54ball]

 Acer, Bob,

 I believe I saw it on here a number of years ago, but there was an engraving of workers grinding barrels.

[jerrywh]

 Here is another early engraving. Notice the man in the background on the right. He is grinding a barrel that would leave marks like the barrel shown by Acer.

[Dphariss]

The ground barrels will have slight "cup" to the flat to match the redius of the wheel. Straight edge should show this. The barrel in the P. Bettis rifle I recently described was  seemingly was done on a wheel by the looks of the three flats under the forend. I was sure they were slightly cupped. Now I wish I had looked much closer or used a straight edge rather than "eyeball".

Dan

[jerrywh]

 True if they were groung across the flats but not if the were ground longitually.

[John C IND]

That might depend on how the grindstone was dressed...

[rich pierce]

If this is a 4 foot diameter stone the arc it would leave on the barrel will be quite subtle. 

[Elnathan]

Maybe I missed something, but it sounds like some folks are suggesting that barrels were forged as straight barrels and afterwards ground to a swamped profile. I very much doubt that was the normal way of doing things, at least prior to the 19th century.

The simplest and least labor- and material-intensive way of swamping a barrel would be to do it while it is still in skelp form. When one is preparing the skelp, leave it thicker on both ends and thin it a bit in the center (or two thirds of the way down, rather). When the skelp is rolled up and welded around the mandrel, the result would be a swamped barrel. When you have finished with the bore, then you hit it with the grinder and the files to get the hammer marks out, even up the flats, make sure that the profile has a nice smooth sweep, etc. Less iron ends up as filings on the shop floor, less wear and tear on grinding wheels and files, and since forging is usually quicker than stock removal, the job gets done faster.

[Acer Saccharum]

I believe the barrels were forged swamped, tapered and flared octagon, and then cleaned up by grinding. I don't know that for a fact.