S&W 1917 gunsmithing question

[Ian]

So I have this basket case silhouette revolver made out of a rusted-out Brazilian contract 1917. At some point in its life after the rebarreling it either had a stuck bullet or, more likely, a lot of very spicy handloads put through it, spicy enough to bulge the bull barrel in front of the frame and bulge the frame enough to taper the barrel threads. The barrel threads start very loose and end up very snug with no wiggle the last turn or so before its shoulder contacts the face of the frame. The flare of the frame opening toward the muzzle end is visible in the light reflecting off of the finish.

Since Glen posted about his snub-nosed, full shroud, custom model 25 I have been thinking of doing similar with this revolver because otherwise it is doomed to remain a bag of parts taking up space here. The question I have is how to deal with the tapered threads in the frame when I re-barrel it? I suppose I could turn and blue a mandrel to identify the exact taper of the threads, offset my tailstock to match, and cut tapered barrel threads to match the frame. The other option would be to chase out the frame threads at the same pitch but slightly larger diameter to clean them up to parallel....though that would be more tricky as far as setup to single-point them in a lathe or make a custom tap. There isn't enough meat to bore the frame to a larger, standard thread size for which I might be able to find a commercial tap. Being a .45 ACP, I don't think that resurrecting this rather than scrapping it would be dangerous with standard loads, but from a machining point of view I don't know what would be the best approach to fixing the tapered frame so the new barrel has full support where it passes through the frame.

Third option might be cut standard threads on the barrel tenon and install it with a liberal dose of epoxy. Anyone know of an epoxy or glue that has 25-30,000 PSI of compressive strength?

 

[Jeff H]

How close is it to 1/2 or 3/8" NTP?

Lowe's, 2" pipe nipple, half way there.

 

[RicinYakima]

FWIW, I used LocTite 620 retaining adhesive and a cross pin to use a 45 ACP barrel into a Remington 820 22LR receiver converted to CF. This is the same stuff used by the shotgun folks to glue barrels into monoblocs. It has 10,000 pounds for inch square strength, will fill .010" gaps. Issues? Can't take it apart, you would have to drill the barrel stub out. It cost more per ml than gold, and I'm not kidding.

 

[Tomme boy]

It is 9.99 on Amazon

 

[RicinYakima]

Must have different Amazon than me. On sale for $23.33 from $29.99 plus shipping and tax.

 

[KeithB]

I'd be thinking about a custom tap made by Regal (there are others) and how to hold the tap square to the frame. Standard pitch, oversize OD, a good toolgrinder should be able to make a custom tap to those specs.

 

[Bret4207]

How about shrinking the frame back to where it's supposed to be? A couple of swage blocks in a press with a mandrel in the threads to protect/limit the swaging. The frames are pretty ductile.

 

[Petrol & Powder]

How about shrinking the frame back to where it's supposed to be? A couple of swage blocks in a press with a mandrel in the threads to protect/limit the swaging. The frames are pretty ductile.

I like this idea, The metal is there, just displaced.
You don't have much to lose.

 

[RBHarter]

The 1917/18/19s were pinned anyway. I don't have a 1937 .

I'm a simple wrench bender that solves problems by bypass or simplest solution. So grain of salt if you will.
Since you're cutting your own threads on a barrel I would elect to do a full dia thread and leave the last 3 or so fat at the base of the barrel . You have some thread contact full length and the extension on the frame side is near friction fit . Leaving the last 2-3 threads fat will reduce the likelihood of further stretch and eliminate any likely walk .

The 45 ACP is only a 23kpsi max cartridge.
Also the 37s were first assembled on leftover 1917s , I can't remember the numbers now but there were 2 contracts and only about 1/3 of the second contract were on new (read heat treated) frames . So like 1500 of 10,000 or something like that. The frames and barrels will probably run all of the 20kpsi FMJ ball you want to feed them .

From a recognized source i can't remember because there was hours of search for 30-45 min to a couple of hours of reading 4-5 years ago .
All N frame parts are the same except Heat Treatment that started lot specific in 1925 and moved to all new production in 1935 . Don't bet on anything older than 1940 to be HT that wasn't built as a HT cartridge.
Another sites 1937 with all of the pre HT frames being used up for the 1937 Brazilian contracts .

If you have access you might get the frame magnafluxed or even wet magged .
I'm not a machinist but I wouldn't remove any more metal from the frame or aggravate the stretch .

There is a story about a German engineer that worked for Dornnier Fokker during WWI . In the 20's he visited an American facility building the next evolution of R&D fighter recon type aircraft . There were several prototypes lined up with the same section of fabric off of them with the same failure of the same structure tube . 1 was the original design with a heavier wall tube the next had the thin wall tube but was sized up the next with a larger yet tube .
He says to the job engineer "vie ist das like dot ? " We're trying to stop the flex . "Why is it over stressing the rest or causing a control problem?" No it's just an undesirable flex point. " If it causes no harm why not just let it flex ?"

In that I found a great deal of truth and explaination of why some designs are like concrete reinforced chromoly and some will do most of the same job with 2 bends in .025 aluminum , case hardening , and through temper ......

 

[Ian]

I like the idea of shrinking the metal back too, but the problem becomes doing it in a way that truly makes a uniform thread inside. Peening against a hardened, threaded mandrel would be the only way, and might be a good one. I could face the frame afterward to re-square it as some metal would be pushed out the front. I'm not really worried about the frame cracking, I know these are soft and malleable and the steel isn't going to work harden all that much with what I'm wanting to do. What I DO want to do is achieve a solid and uniform contact between the barrel and frame so that it doesn't bulge again at the front of the frame from normal use since the barrel is paper-thin through the frame and requires frame support under normal pressures.

The easiest would be to single-point the threads a little oversized, but I don't want to spend a week building and balancing a face plate jig to hold the frame. I also don't want to buy a $300 custom tap to fix a single, $50 revolver.

 

[KeithB]

There’s that money thing again, LOL. Any idea what the nominal thread specs are?

 

[Ian]

I haven't measured it yet, Keith, will do some studying tomorrow, please stay tuned.

 

[fiver]

cut a cone shaped adapter.
or cut the barrel and use a shroud like Dan wesson does.
that pulls and pushes at the same time.

 

[Ian]

Rich, I think mine is a 1946 contract made from the older, 1917 surplus frames. It has a rounded top strap with u-notch sight groove and the remains of the Brazillian crest on the side plate. Second contract, IOW. Not HT'd frame.

 

[Tomme boy]

Silver solder the frame threads and run a tap in? I have fixed all kinds of threads in machines by welding up the hole and running taps back in.

 

[Bret4207]

I like the idea of shrinking the metal back too, but the problem becomes doing it in a way that truly makes a uniform thread inside. Peening against a hardened, threaded mandrel would be the only way, and might be a good one. I could face the frame afterward to re-square it as some metal would be pushed out the front. I'm not really worried about the frame cracking, I know these are soft and malleable and the steel isn't going to work harden all that much with what I'm wanting to do. What I DO want to do is achieve a solid and uniform contact between the barrel and frame so that it doesn't bulge again at the front of the frame from normal use since the barrel is paper-thin through the frame and requires frame support under normal pressures.

The easiest would be to single-point the threads a little oversized, but I don't want to spend a week building and balancing a face plate jig to hold the frame. I also don't want to buy a $300 custom tap to fix a single, $50 revolver.

Take it back as far as you can/feel comforatble doing, chase the frame threads and then use something like the Loc-tite mentioned. Magnafluxing wouldn't be a bad idea, many machine/engine shops have them on hand. (DUH!!! I bet you have something in that line at work!) Anyway, I would rather not see any more material cut from the frame if it were me. We're taking thousandths, but then you're into a custom barrel too.

 

[358156 hp]

Must have different Amazon than me. On sale for $23.33 from $29.99 plus shipping and tax.

LocTite is one of the most commonly counterfeited products out there. I got a screaming deal on a bottle of high end stuff and while the logo was correct, the product inside was much less viscous and the rest of the label was written in a different order than the original bottle. The original was purchased directly from a Loctite Distributor.

 

[JustJim]

Counterfeit LocTite?!?!?!?! I'll have to keep an eye out. For 20+ years my source has been a local aviation manufacturer, where they have to discard LocTite when it expires. From the sound of things, I'll be suffering sticker shock next time I buy some.

 

[Brad]

Amazon is rife with counterfeit items. The packaging on most looks pretty damned good. My daughter had a counterfeit cellphone case and only learned of it when she called about the lifetime warranty after it cracked. Manufacturer said nope, Not ours.

Amazon is also the largest dense in the world. Lots of shoplifted items get sold there. Look into organized retail crime.

 

[Ian]

Bad news, looked for....and found....a crack in the front of the frame.



Frame thread minor diameter is .642" at the cylinder end and .652" at the muzzle end behind the counter-bore.

Barrel thread major diameter is .659" at the cylinder end, .665" in the middle, and .671" at the muzzle end behind the counter-bore.

Cracked frame isn't going to support any pressure transferred from the barrel, so no point trying to make a good fit.

I could vee out the crack, tig it up, and heat treat the whole frame IF I knew what rod to use and what heat treat times and temperatures to use. Then there would be the challenge of trying to pick up and single-point a 36 TPI thread and clean up a lump of weld on one side of it. Might be easier to clean out the threads with a boring bar, weld the frame hole up solid like Tomme mentioned, and redrill/thread it with the proper tap from Brownells.