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david50

45 Cal.
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I have a smoothbore barrel which has had the ventliner hole drilled out too large for even a 3/8 size ventliner. my question is can the hole be filled by welding some how and then redrilled.
 
D&T for a bolt, file flush with the barrel, D&T for your liner.......

I don't think welding will be safe :shocked2:
 
I had the same situation and made a tight fitting copper plug for the bore and the welder filled the hole up. It's still going strong and the LR has been shot 100s of times.....Fred
 
From what I can dig out on the internet, if there is a chance of the barrel being made out of a leaded steel like 12L14, don't weld it.

Welds on leaded steels usually have micro-cracks due to the lead in the steel.

If your sure the barrel was not made from a leaded steel like 1018 or 1020 steel, it can be welded without a problem

In all honesty, if it were my barrel and I wasn't sure what it was made from I would consider tapping the hole with a 7/16-20 UNF thread and buying a 7/16-20 bolt to serve as the material to fill the new hole.

This could be installed with Loc-Tite to keep it in place.

A caution about doing this though.
If the barrel wall in the area of the thread is .200 or less in thickness I'd write it off as scrap.
If the wall is thicker, it should be able to withstand moderate powder loads but I wouldn't shoot any hot or 'max' loads in it.
If the breech pressure reaches 6000 psi there will be a force of about 1000 pounds trying to blow the plug out of the side of the barrel.
 
question to the smarter guys on this, since we do not have a picture. Could the barrel be refit with patent breech? I was thinking cut the breech end off and re-fit with patented breech to the same length. Probably to complicated a task.
 
I would drill and tap for 7/16-20 and have a machinist make a vent liner, to fit. A 7/16 stainless bolt, with the head cut off, could be chucked in a lathe, and coned, then cut a little long with a screw driver slot. Install in the barrel and file flush. I'm taking Zonie"s suggestions, just a step farther and all the other precautions, he mentioned, apply.

Oh, I forgot to mention, you will need a bolt with a shank, and cut it above, so you will have a bevel, keeping the liner from screwing in too far. Short bolts are treaded, all the way to the head. Longer bolts have a shank between the threads and head.
 
Any reason not to simply drill a vent hole in the installed bolt section? Call it an over-size custom vent liner. Might have to replace it a little more often, but....

Just seems better to cut to the chase than to have two sets of threads in one spot.
 
That's what I'm suggesting, a custom made vent liner with 7/16 threads, instead of 3/8 threads. In OP he said, hole was too big for a 3/8 liner, however he really didn't give the actual dia. of the hole. I was assuming that it was stripped. In that case, drill out for a 7/16 and custom make a liner, to fit. I never suggested to put a store bought liner in the plug, I'm talking about a coned and drilled, custom over-size vent liner made out of a stainless bolt.
 
david50 said:
I have a smoothbore barrel which has had the ventliner hole drilled out too large for even a 3/8 size ventliner. my question is can the hole be filled by welding some how and then redrilled.

Yes, it could possibly be done. No..... :shake: I would never do it or trust one that had been welded. WAY more chance of rupture than I want to take, or risk injury to someone later.

Keith Lisle
 
Somewhere in the back pages on here there is a thread about somebody doing that precise thing, He D&T for a bolt, concaved the end of it and then drilled a hole, viola! a homemade vent liner. I even think he used a stainless steel bolt.
 
I've done it, not hard to do at all...I simply used a 1/4 inch stainless steel rod, counter drilled from the back side, screwed in, filed flush and drilled a vent...No problems...
 
Free advice being worth what you paid for it:

If your sure the barrel was not made from a leaded steel like 1018 or 1020 steel, it can be welded without a problem

The only trouble with this is that you will rarely find a welder who is not an expert and who is not the best.
The very very best welders that the Nuclear industry, high pressure gas industry, Aerospace industry etc can muster fail enough radiographs to keep an entire industry fat on the rigours of Quality Control.

More then likely any weld will hold even if it is a matrix of inclusions and heat cracks. But the day that someone standing 20 yards to your right ends up with a piece of barrel in them 200 bucks for a new barrel will seem cheap.

If you 'must' weld it, perform the weld repair (but not the drilling) and then head down to your local non destrutive testing shop. 9 times out of 10 they will be happy to have something diffrent for a young guy/apprentice to learn on and likely will not charge you much if anything to take some radiographs or map the repair with Ultrasonics. deliver it with the breech plug pulled. This same shop can also tell you what material the barrel is made from in 5 mins.

The big problem here is that smack in the middle of the repair you are threading in stress risers galore. It is not very far from these stress risers to the area where you will most likely develop cracking ( heat effected area between parent material and weld material). A failure will be a triangular piece of weld material with your vent liner thread on one side.

If it was mine and It needed to be done I would have it welded by a boiler maker with lots of experience on upper level boiler tubes and I would drill a vent and not thread it for a liner.


Or just go for it,
In one of Kit Ravenshear's books he gives instructions for welding both vent holes and barrel extensions. IIRC his big trouble with weld repairs for restoration was matching finish. No mention of catastrophic failures.
 
Tetsa Prowler said:
Or just go for it,
In one of Kit Ravenshear's books he gives instructions for welding both vent holes and barrel extensions. IIRC his big trouble with weld repairs for restoration was matching finish. No mention of catastrophic failures.

Just because someone put something in a book & there is no record of it failing, does not mean it is the correct way to repair it. :shake: If you remember, Bleeding People was for may years a documented way or curing people of hundreds of ailments ? For a long time, regardless of the ailment, well, obviously they had way too much blood in them. :hmm:

SAFETY......... Always... comes first. IMHO, the only safe way to fix this barrel is to cut it off & rebreech it, or replace the barrel.

Welding it up is not safe.... Way to many If's and Wonder What's involved.

Drilling out & retapping it would bring the new plug out way past the flats...... Plus you are threading into the side wall with a big plug & if he could easily do that he would already have the barrel repaired.

Send the barrel to Bobby Hoyt & have him cut it off & rebreech it, or buy a new barrel & fit it is the safe & sure way to repair it.

Is it really worth taking a chance on someone getting hurt from a ruptured barrel ?
We are not playing with Tinker Toys on here.

Fix it Correctly or scrap it.

Keith Lisle
 
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