doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Burst Barrel Repair--Sleeving & Other Options

That's correct Saad. They used to solder it in, now some weld it.

What is brazing?

And which type of welding is performed? In layman terms I know of two types of welding, one is electric welding using a welding rod and welding unit, the other is by using a gas torch and thin metal rod (steel, brass, etc).

Saad,
Brazing is typically a term used to describe using a nonferrous metal such as bronze or high silver content alloy for bonding two pieces of metal together, much like soldering only higher temperatures are needed. The term brazing also indicates the bonding metal is a lower temperature than the primary metal parts, unlike welding. "Brazing" that I'm familiar with has included bonding of steels, titanium, and aluminum.

http://www.key-to-metals.com/Article36.htm

Thanks Chuck!

Could you please further elaborate that how the chamber is bored out (steps 2 & 3 in drawing). I mean what tools are used.

What should be the minimum wall thickness of the turned down barrel at chamber area (setps 5 & 6 in drawing)?

Another stab at an explanation of the process:

"Sleeved bbls - An economical method of bringing new life to a damaged pair of barrels, regardless of their original method of jointing. The ribs are removed. The barrels are cut off 3" - 4" from the breech end and discarded. The bores of the remaining breech-end are reamed out oversize. New tubes are fitted down into the original breech section and filed down to fit flush. The original ribs are then replaced.

Sleeving is considerably less expensive than building a completely new set of barrels. Much of the time required to build a set of barrels is concentrated in the fitting of the breech end to the receiver; this work is salvaged through sleeving. Sleeving can be recognized by a pair of circumferential lines around the barrels a few inches from the breech; the more invisible, the finer the job. A sleeved gun should always be identified as such amongst the proof marks, and if done in England must be properly reproofed."

Saad,
when I bored the chambers, I cut the barrels at about 8" from the breach, then simply turned a piece of steel bar (mandrel) in the lathe to fit the bore, TIG tack welded the bar in one of the barrels, put the bar back in the lathe, indicated (trued) in the breach end of the chamber and bored just over 3" deep to the desired diameter, removed the bar and barrel from the lathe, cut the tack welds, repeat the process on the second barrel, cut the barrels to just over 3" with a saw, turned another bar about 2 3/4" long that the newly bored oversize barrels would fit over tightly, put the barrels on the bar with the forward end of the barrel where you can face off it squarely to the bore. Repeat on the other barrel.

It's extremely important that the forward face of the barrels be perfectly square to the bores. It's also extremely important that the bored out chambers follow the original line of the bore. So, I didn't use reamers for any of the work but rather indicated in and bored with single point tools.

Thanks Chuck.

So, traditionally reamers are used for this purpose?

Saad,
I don't know what is "traditionally" used since the one that I did was the one and only. Professional gunsmiths with English training like Mr. SDH and others may have more direct experience traditional methods and likely have done it much more than I have. As a former machinist, I can tell you that a reamer will tend to follow a hole axis, where a part that you've spent time indicating in and want the axis of the new hole to follow that axis, will be best done by singlepoint boring.

Chuck,

The problem is that, I see in your method it works with both barrels cut. Whereas, I am looking for a solution to sleeve one barrel only, the other one will remain intact during the process.

Do you consider it is possible to machine it using lathe with second barrel still intact?

It is possible to sleeve a single barrel on a double, my uncle has a SKB 100 with the left barrel sleeved. This would be possible on a lathe with the proper tooling and set up and the ribs removed. A special cutter may need to be made. I would think a set up such as is commonly used for opening chokes(different cutter of course) to square cut off tube. As for opening the old chamber, a reamer will work fine if you take light cutts, adjustable reamers work great for this. Good luck,
Steve