Under lug staple

[Kapow]

I have a southern mountain rifle that I put together as a kit. The under lug staple has never taken to the barrel properly so I tried to weld it with an arc welder. It seems that the weld will take to the barrel and the lug individually but not joining the two. Are there differences in the metal types that are keeping the two from sticking? Any advice/tips?

 

[dave_person]

Hi,
I urge you to avoid doing any welding on a barrel. You may ruin it. Rather, simply use low temp silver solder or even standard plumbers solder to secure the lug.

dave

 

[daniel collums]

if you do try it again use a rod that is nickle or try a stainless rod.

 

[necchi]

Hi,
I urge you to avoid doing any welding on a barrel. You may ruin it. Rather, simply use low temp silver solder or even standard plumbers solder to secure the lug.

Sage advice,,
Welding (?) :nono:

 

[Pete G]

Steel is hardened by heating and then cooling, sometimes by quenching in liquid but often by just cooling in air. Welding can very easily produce a brittle spot that can be dangerous in a barrel. The way to remove the brittleness is to heat treat the barrel in order to anneal it, which is beyond the capabilities of most home workshops.

A barrel staple should be set into a shallow drilled hole and peened into place by displacing metal next to the legs. Solder probably won't hold. You might be able to dovetail an underlug into the right spot instead.

 

[crockett]

That was my understanding, that if you use staples- it is a pressure/mechanical fit. No solder or welding.
Will it hold????? A civil engineer told me the bolts on I beams on skyscrapers are held by friction, the bolts simply hold the parts tightly together. So I'm told.
TOW has some information on setting staples in a barrel.

 

[Vaino]

I wouldn't weld a bbl, but low temp soldering should do the job.....afterall, the lug isn't really doing that much, is it? The forestock on LRs is quite flimsy and not a whole of retention is needed.

As far as staples are concerned....used them on my first 2 LRs and then went to a dovetailed bbl lug. Never liked the idea of drilling into the bbl even though the drill press stops and a drill collar were used.

Also, no matter how the peens were done on the staple legs, they still didn't look nice and neat.

Are you sure that there's not enough metal to peen?....Fred

 

[MSW]

I'm coming down on the side of the consensus: don't weld the barrel. a decent job with solder should hold up just fine.

just one guy's opinion, mind you, but welding a barrel just isn't a good idea from where I sit.

good luck with your project!

 

[dave_person]

Hi,
The problem with welding is that you may accidentally harden the steel making it brittle but as likely, you will produce scale in the bore, which could ruin accuracy. Solder will hold the lug in its hole. Hopefully, you can peen a little more metal around it as well to help lock it in. I hope you have not already damaged your barrel.

dave

 

[19 16 6]

The biggest problem with arc welding is the distortion due to shrinkage. What ? Don't believe me ?
Lay two pieces of flat steel on the bench top. Now lay a little weld to join the two, barely more than a spot & see what happens. The weld pulls & the outer edges of the two pieces raise up off the bench. The two pieces are no longer flat but a very slight V shape.
Also get a straight tube & check it with a straight edge. Now lay a little weld on the tube, grind it back & check the tube again with the straight edge. You will find that the straight edge no longer touches the tube at the point of weld. It is bent. This is all air cooled & if you water quench the weld the affect is at least doubled.
Maate, get a tight patch on your cleaning jag & run it down the bore to see if the bore is constricted at the weld. I would also shoot a laser along the barrel or use a straight edge to check for straight.
How much weld did you do on the barrel ?
O.

 

[TMan51]

As far as staples are concerned....used them on my first 2 LRs and then went to a dovetailed bbl lug. Never liked the idea of drilling into the bbl even though the drill press stops and a drill collar were used.

I was wondering how deep staples go relative to an underlug?

I ask because I'm looking at staples as the TOTW staple tools look easier with my balance of tools and talent.

 

[necchi]

Not much, it's easy to drill shallow holes.
But like Fred said,, the staking tool doesn't really do a nice job of seating the metal against the staple.
I've used the TOTW items you mention and they do work, but I wasn't happy and added a bit of solder at each stake hole of the staples.
(that was also easy enough to do)
Another argument against the drill/stake underlugs is just what I mentioned,, the staking tool doesn't do a pretty job,, so some folks will start moving the tool around tipping it and whatnot, banging on it really hard to move the metal around the stake,, this can put a dent in a thin walled barrel that noticed in the bore.
It's just one way that system can be abused and fail.
A little forethought, care and a little solder and they work just fine.

 

[TMan51]

this can put a dent in a thin walled barrel that noticed in the bore.

Thin walled barrel. What would you consider "thin"?

I have wondered about that number for a while.

You can definitely feel the effect of roll stamping on a modern rifle with a tight patch. Can you hammer on a staking tool hard enough to be a problem with a .45 barrel 13/16" across the flats?
Would cutting a dovetail remove enough steel to be a potential problem on the same barrel?

 

[necchi]

Well it's really a finesse thing that's hard to quantify with a web discussion.
Someone could beat the snot out of any barrel hard enough with a punch (that's basically what a staking tool is) and cause damage to the bore, right(?)
I used them on a 13/16 40cal and I was certainly concerned when I read here of some of the pro builders experience with these things and actually doing that damage. That's why I just lightly upset the metal to hold the staples in position and soldered.

Same thing goes with dovetails, sure a guy can go too deep. I know I went deeper than needed with my first sight dovetail on a 15/16 barrel. It doesn't take much to hold things securely.
Maybe some of the more experienced builders will chime in about dovetail depth, I know there's several great topics about dovetails in the archives.

 

[Col. Batguano]

Just a thought; Other than centering the downward or upward pressure, is there a practical reason that staples and lugs couldn't be offset from the center line? That would give you a bit more steel to drill in to, and more wood to work with if you intend to keep the lugs blind to the RR channel.

 

[longcruise]

I did that while repairing a GPR. It was a 15/16 54. There was probably plenty of meat there to allow center but it seemed like a good idea.

Of the few drilled and staked lugs I've done, I have gone quite shallow with a very slightly oversize drill. The lug legs (lug made from a nail) were slightly upset to create a foot that just fit the hole. Some were upset very slightly with a pointed punch just to hold them in place and then soldered others simply soldered. All are holding well.