crush thread hybrid barrel on late model S&W?

[JIMinPHX]

Does anybody here know about crush fit thread hybrid barrels on late model S&W revolvers? I have a 4” K-frame with an oversized groove diameter & I want to put a better barrel on it. S&W says that they will change the barrel for me (for a pretty penny) but they will not guarantee the groove diameter that I will get. That is just completely unacceptable & since I don’t know any pistolsmiths within driving distance of here that I trust, I think that I am on my own with this one. I’ve been through the Jerry K book & he gives a pretty reasonable description of what to do with a pinned barrel, but the crush fit hybrid that I have just isn’t covered there. Has anybody here been through a barrel change on one of these? If so, can you give me a preview of what to expect?

Thanks,
Jim

[lathesmith]

Jim, I am not certain what you are referring to as a hybrid. Is this just a nonpinned barrel, or is it one of those that has a shroud and barrel that requires a special wrench for the rifling to remove it?
I have not worked with the shroud-type barrel. IIRCC Jerry's book doesn't diferentiate between a pinned or non-pinned barrel, as far as having different fitting procedures. You might take a look at the following link, I found it very helpful and actually used it as a sort of "guide" when I fitted a new barrel to my "N" frame:

http://preview.tinyurl.com/yvwqh8

Pretty entertaining reading, even if it don't apply to your "hybrid".

lathesmith

[JIMinPHX]

Hi Lathesmith & thank you for that link. That was a good read.

Yes, this "hybrid" is the barrel with the shroud. I have not been able to find anyplace to buy the special bore wrench for grabbing the inside of the barrel, but I think that I have a pretty good game plan for getting around that one. I was planning on dropping a 1/4 long-arm Allen wrench down inside the barrel, then filling it with potting compound, like cerosafe or something. That should give me a good solid, well-distributed grip that is removable below 200 degrees F, so tempering should not be affected. Beyond that I was wondering what to expect.

Does that shroud just spin freely once the barrel is loose? Are there only the two parts? Or are there more? Is there someplace that I can get a diagram of the new style barrel? What kind of risk am I running by removing the original crush fit barrel? Will there be damage to the frame threads? Will I need to retap? Will I need to sleeve? Can I install a pinned barrel? Will the frame threads be too loose from already having a crush fit barrel installed & therefore make a pinned barrel difficult to attach rigidly?

I'm not trying to saddle you with all these questions Lathesmith. I'm just putting them out there for everyone to take a look at.

Thanks again for the reply.

Jim

[lathesmith]

Jim, check the S&W forums, it seems like I have seen some of these questions there. IIRC, you are on the right track with using cerrosafe to make a barrel wrench. For the other stuff...I saw where one poster said an older barrel could be fitted to a new (shroud) frame, but not the other way around. Beyond this,I don't know. Check it out, join if you need to, and ask a few questions there. There are some nice guys on this forum that seem to know S&W's really well.

http://smith-wessonforum.com/eve/forums/a/frm/f/580103904

lathesmith

[JIMinPHX]

Thanks Lathesmith, I'll give them a try.

[runfiverun]

hand loader did an article on this iirc
s&w wont even sell this wrench to gunsmiths.
so the cerrosafe deal is the only way to go.
i believe what i read is exactly what is going on here
so much for customer service anymore.
seems like a lot of gun companies have the take it as is or too bad you already bought it
and thats what you got. attitude

[ra_balke]

Don't shout at me for this ...ok ?
I once fitted a 24tip bbl to a 20 tpi frame in a Colt single action.

I did not want to damage the frame, so I simply overthreaded the 24 tpi bbl to 20 tpi.
It was butt ugly, but it worked.

x

One time I had a model 95 or 96 ( I get confused ) bbl in 7mm that I wanted to fit to a mauser 98 action.
I turned most of the threads off down to the shank, then I fine threaded it....20 tpi or so.

Next, I took a hunk of steel boiler pipe I think, and lathe bored the inside , then inside threaded it to match. I screwed the hunk of steel on to the barrel shank, turned the mess down to mauser 98 diameter, then threaded it to mauser tpi 12 tpi I think.

I screwed the thing together, headspaced it, and it worked fine.

[JIMinPHX]

I’m not going to shout at you for saying that, but I’ll let you know that I’m looking to do a little more of a first class job than that. I want to keep everything at or above factory quality.

I’m having a tough time finding good info on this. I’ve scoured the S&W site. There is only scant info there. I get the impression that not too many people have messed with these things yet. I also get the impression that the crush fit is a bad idea from the word go. Apparently, it has a tendency to cause a constriction in the barrel diameter under the threads when the whole mess is assembled.

I’m going to keep digging for more info before I dive into this project any deeper. If anyone has any other ideas where I should be looking, I’m all ears.

Thanks,
Jim

[HeavyMetal]

The experience you are having is the reason I refuse to buy another Smith & Wesson Product! If I had known that T/C had been bought by them I would have given it another bit of thought before I bought my used Contender!

The honest truth is: as long as we give(any gun company) them money they will have no need to listen to us when we demand a repair or replacement part!

My understanding is you plan to change this barrel yourself in an attempt to improve the pistols accruarcy?

I've changed a barrel or two in my day so I will go out on a limb here and make a few suggestions.
Bite the bullet and sell the gun and get out now! This isn't what you want to hear I'm sure but it's going to be the least painful less expensive way to go!
The reason I'm saying this is you will never get your money back if you ever decide to sell the gun and( this is more likely) you'll actually depreciate it because no one knows who you are or the quality of your work!

The second suggestion is: send the gun to one of the big boys! like cylinder and slide or Bowen custom, or Gary Reeder.

Yes this will cost you some cash! However if and when you decide to sell you have now got documented proof that the factory issue was repaired by a known name in the industry! With that information you might be able to recover at least the sale price of the gun.

I'm not trying to stop you from learning something! I'm simply saying what is it you going to learn, and do you really want to?

[shunka]

Jim - Unfortunately, I must agree with heavymetal. My personal feeling is that the "crush fit/shrouded barrel" is a bad idea based on fast/cheap assembly. It was originally touted as having better accuracy, ala the old Dan Wesson, with the barrel being held under tension. Unfortunately I do not think a crush fit is such a good idea for accuracy (IMO) - after all look at some of the best shooting custom target rifles - the custom smiths turn the barrels on with as little as 30-40 ft-pounds. One fellow even spins them on "hand tight" - he claims they never shoot loose and has better than MOA accuracy. Perhaps he has much stronger hands than me.

The barrel constriction at the frame can be determined by pushing a tight oiled patch or pure lead round ball from the muzzle and "feel" for it. One fellow I know had such a tight bore at the frame, and found it was crap in the threads. after disassembly and wire brushing both the frame threads and barrel threads, the constriction was gone. This was on the old "pinned" S&W.
You might be better off trading it for a used pinned barrel N-frame... (my personal preference)

[felix]

They will never shoot loose when the barrel is turned into the frame the opposite way of the twist. The barrel must be just tight enough to maintain the same vibration frequency per shot. ... felix

[JIMinPHX]

Well, I’m not going to try to sell off a gun that I know has a problem, & I don’t have any pistolsmiths within driving distance that I trust to do a first class job, so those two options are out for me. My primary option of sending it back to Smith didn’t work out too well, so that leaves me with a project on my bench. I’m not worried about getting my time & money back that I put into this thing, because I don’t ever plan to sell it. Smith doesn’t make K-frames anymore so I don’t want to let this one go. I just want to get a better quality barrel onto it. I’m a qualified machinist, so the work itself doesn’t scare me. I just need to gather all the necessary information & find a good barrel before I dig into it. The over-diameter barrel that it came with from the factory is simply not acceptable to me. I want this thing to be right & I’m willing to do what it takes to make it that way. I do thank everyone for the well-intentioned advice though, even if I’m choosing not to take you up on your suggestions.

Regards,
Jim

[MtGun44]

"Smith doesn't make K-frames any more" ---

A quick look at their web site shows the Model 10, 64, 67, 617 which
are K-frames.

Wonder how this rumor got started?

Bill

[S.R.Custom]

Well, I’m not going to try to sell off a gun that I know has a problem...
Why not? S&W doesn't seem to have had a problem selling it to you...

[JRD]

Jim,
Out of curiosity, what is the actual groove diameter of your S&W? I'm assuming it's a .38 or .357 caliber. What kind of groups have you been getting?
Jason

[JIMinPHX]

"Smith doesn't make K-frames any more" ---

A quick look at their web site shows the Model 10, 64, 67, 617 which
are K-frames.

Wonder how this rumor got started?

Bill

The 65's & 66's are finished. I think that the K-frames they have left are just what is still in the warehouse. I believe that they stopped production about 2 years ago.

[JIMinPHX]

Jim,
Out of curiosity, what is the actual groove diameter of your S&W? I'm assuming it's a .38 or .357 caliber. What kind of groups have you been getting?
Jason

Off the top of my head, I think it was like .362 or something like that. I got horrible leading in the first inch & a half of the barrel after only a few shots. The throats were all just about right on the money at like .3569-.3572 or something like that. I'd have to go dig up the letter that I sent to S&W with the gun to give you the actual real numbers, but these are probably pretty close.

[JIMinPHX]

Why not? S&W doesn't seem to have had a problem selling it to you...

Because I'm not like S&W...in more ways than one.

[S.R.Custom]

Because I'm not like S&W...in more ways than one.

I understand the sentiment, but I don't think it applies, and here's why: You are not responsible for what S&W turns out. It's not your name on the side plate. Keep in mind, too, that the things that bother you about the gun may be totally inconsequential to the next guy. Let him decide what is and what is not suitable for his purpose.

That said, I recently sold a S&W that I didn't like, and I had pretty good reason not to like it. But rather than assume responsibility for others' work, I got rid of it. I looked at it as an opportunity to spread the word about S&W's dedication to quality. ;)

[JIMinPHX]

I hear where you're coming from SuperMag. If I sold the gun to a guy that only shot normal store-bought J-ammo, he would probably never have an issue with it. To him there would be nothing wrong with it & that would be a fair & honorable sale. Unfortunately, to my own detriment sometimes, I have a problem with letting something like that slide. It's also a craftsmanship thing with me. I'm the same way with motorcycles. I never buy a new one. I usually get an old shovelhead or something & fix it up as I ride it. After I've owned it for a few years, it gets to be pretty spiffy. That’s usually when I see the next junker sitting on the side of the road somewhere with a for sale sign on it & the whole cycle starts again. It’s like I need to have stuff that needs me, or something crazy like that. In this case it’s more complicated. I can't just go out & buy a new 4" model 66 that is good to go right off the shelf because they don't make them any more. If I want a nice one, which I do, then I either need to get real lucky & stumble upon somebody that is selling a cherry old one or I need to do something with the one that I have. I'm not feeling real confident about my chances of finding a nice one popping up right in front of me for sale any time soon, so I'm thinking that I'm going to be playing games with this one for a while instead, whether I like it or not.

[HeavyMetal]

Jim:
I appluad your devotion to your ethic's! I also say go ahead on if you think you got the skill level!

Now lets take a hard look at your problem. How worried are you about saving the original barrel /shroud? The reason I ask is even if you get it apart successfully, since no one can buy a wrench from the maker, who's going to buy it as spare parts?

If your not going to sweat the old barrel/shroud then cut it off! You might only have to cut through the shroud. This will release the tension and everything will simply unscrew!

At that point it's just a matter of measuring the existing thread diameter in the frame and deciding on the next step!

You might get lucky and find that a standard barrel will screw right in. As I recall a friend had a Dan Wesson the used much the same system to provide interchangeable barrels and it had nothing fancy at the frame end. You just screwed the barrel in until it made contact with a specific size feeler guage then dropped on the shroud and added the nut on the muzzle end.

The trick was to always put the nut on with the same amount of torque each time it was changed and not let the barrel cylinder gap change while you were doing the tightening!

The "crush fit" wasn't in the frame threads but in the compression of the barrel shroud to keep everything tight!

It just so happens that I am currently doing a barrel swap on a model 66 for a friend. He has an old round butt 2 inch gun and hates the barrel length. I aquirred a 6 inch barrel at a gun show that has good rifling inside. This give me access to thread size, diameter, and basicly all the measurements you'll need to figure out your problem and a cure.

figure out what your gonna do with the barrel and then post your needs as to dimensions and we'll supply as needed!

[JIMinPHX]

According to the Jerry K book, the K-frame barrel should have a .540”-36 thread. He’s talking about the older-style pinned barrel there. What he doesn’t seem to say is what the pitch diameter tolerance is supposed to be. I suspect, but don’t know for sure, that the “crush fit” threads have the same nominal specifications with a different PD.

I’m not real worried about saving the shroud or the original barrel once I have a new one on the gun. I don’t want to destroy the original parts until I am confident that I will be able to mate the new barrel successfully though. I’m also not yet convinced that the squeeze fit comes from the push against the shroud. There may be tapered threads involved or something like that. I’m not saying that shroud pinch isn’t where the crush comes from, I’m just saying that I'm not yet convinced that it is in this case & I don’t want to make any moves just yet based on an assumption that I do not have good confidence in. We used to have a sign on the wall of a bike shop that I worked at about 20 years ago. It said “intelligent inattention is preferable to unintelligent tinkering – in other words, if it ain’t broke, don’t fix it”. I still try to let myself be guided by that advice. We had some other nifty stuff on the wall there too. The guy that owned that place was a real character.

I would actually prefer to go with an older style pinned barrel, both for performance & aesthetic reasons unless there is a good reason not to. Come to think of it, I prefer the older ones for cleaning too. That recessed muzzle on the new style is a graveyard of lead spatter that does not like to come out.

If you have a way to measure the pitch diameter of both the 2” & 6” barrels that you are now working with, I would find that information very interesting. Also, if someone has a crush fit barrel that goes to a K-frame, I would love to know what the actual thread measurements on that are to. In the mean time, I’m going to sit tight & continue sniffing around for more info. I don’t want to take a chance of botching this thing up. I’d rather take my time with it.

[HeavyMetal]

I think your on the right track! Lets see if we can't get those numbers for you before you unscrew anything.

I don't have a way to check pitch depth. I think you might need a "comparator" to do that with.

However I am going to suggest one of us PM Buckshot. I hear he's the wizard of such things and he might be able to shed some light on either the PD for the crush fit barrel or how to read the PD.

The other option is to try and figure out how to contact Jerry K. he may have info that never got into his current editon?

I believe Buckshot has a sticky posted in one of the other headings and from that he can be PM.

I am interested in what he has to say but I think you should do the PM as it's you who will sooner or later unscrew that barrel!

This way nothing gets lost in "translation"!

I do have the 6 inch barrel off the gun but not the 2 inch. If I don't get hit with a bout of the lazy's I will tackle that this week end.

Keep me posted.

[JIMinPHX]

Measuring a Pitch Diameter is one of the first things that you learn how to do before you start single pointing threads on a lathe. I’m actually an old hand at that myself. (old hand = I used to do it a lot many years ago, but not much lately) The traditional method is the three wire method, where you put one wire under the threaded item & the other two on top. They all go in the valleys of the threads. You then measure across the tops of the wires with a micrometer & do a calculation to determine the Pitch diameter.

For a 36 pitch, you would use a set of 0.018” diameter wires. The first thing that you have to do is calculate the “constant”.
Constant = 3(wire diameter) - .866(pitch)
In this case
Const. = 3(.018) – (.866)x(1/36) = .02994444444

You then subtract this number from the measurement (M) to get the Pitch diameter (E or PD depending on who you talk to) because the basic formula is PD (or E) = M - Constant. In other words, If you measured .5519 across the wires, then the PD would be .5519-.029944=.521956 which I would round off to .5220. That is about where I would expect you to find the PD to be. Either that or 1-2 thousandths below there for a non-crush fit.

[HeavyMetal]

It's amazing what you forget when you haven't had a need to do it. I do have a machinest's book that actually shows this method of find the PD.

If I can find some .018 wire I will dig out the 6 inch smith barrel and take some reading for you!

[JRD]

Jim,
If you are pretty handy with a lathe, I think you will be able to make your own custom hybrid barrel. Your idea for casting your own barrel wrench will work. Do that and unscrew your barrel. Do not attempt to spin the "shroud" or outside shape of the barrel in relation to the frame. Only unscrew the inner "sleeve" using your wrench that drives the rifling.

Once the barrel is off, you will see how the shroud, sleeve, and tabs on the frame work. You will not be able to install a conventional one-piece S&W barrel on your frame unless you mill off the frame tabs. Personally the two piece barrel system, I think is superior to a one piece barrel because you are not creating any constriction by the threads. The entire barrel is uniformly in tension. That said, it is different than the way they used to do it and the looks don't really compare to a nice tapered one-piece barrel.

Once you've got the old barrel off, buy a piece of rifled match grade barrel stock. I'm sure you can find sources on line for a section a few inches longer than you will need. Then turn that piece of barrel blank down in your lathe to the same profile as the existing sleeve. You can crown it the way you like and make the forcing cone the way you like. You may want to leave the forcing cone end a little long to custom cut your B/C gap when you are done.

I think the frame threads are as Kuhnhausen wrote and the barrel stays on the frame by the torque and putting the shroud in compression. There should be no interference in the threads. After you single point your threads on the lathe, I'd suggest glass beading the threads to take any whiskers off.

Make a new rifling wrench to fit your new match grade barrel. Oil the threads to prevent galling when the screw your new barrel on and reassemble. The barrel should take a fair amount of torque. I think you'd want to be in the neighborhood of 35 ft-lbs using a torque wrench.

Then you'll have a gun with match grade barrel and precision crown that otherwise looks like the factory gun.

Thats my $.02. Let us know what you end up doing.

Jason

[JIMinPHX]

JRD, you have some nice ideas there. I wouldn’t mind keeping the original barrel shroud if I could get a barrel with a non recessed crown, & if I’m turning my own down out of a barrel blank, then I can make it what ever I want. Suddenly, the thought of keeping this thing looking stock doesn’t sound so bad anymore. I thank you for that recommendation.

Since you know about the tabs on the frame, I’m going to assume that you’ve had one of these apart before. That’s music to my ears. I’m still concerned about the threads gauling when I try to unscrew this thing. For that reason, I’m going to wait until I hear from 3 or 4 people that have pulled them off so I have a good idea of what to expect. I also want to wait until I get conformation on that torque number that you gave me before I go trying to screw anything back together again. I’m not in any rush here. I’m going to sit tight until I’m confident that I have all my ducks in a row. Then I’ll start to mess with it.

As for cleaning up the burrs on a single pointed thread, I’ve always had good luck hitting them with a 3 cornered Swiss-pattern file that is kicked off about 5-10 degrees & then a gentle touch with some 400 grit cloth over the crests. I haven’t tried bead blasting them before. I’ll keep that one in the back of my mind.

By the way, at $.02, you’re selling yourself short.
;-)

Thanks a lot,
Jim

[bohica2xo]

Greetings. I am new here, but certainly not new to the gunsmithing game.

Jim:

Don't sweat the "crush" term in that assembly. S&W can't build a barrel tight enough for good accuracy, what makes you think they can make threads closer than a 2A fit?

Seriously, consider the factory assembly method. They use a steel tool in the rifling to tighten the barrel - how much torque do you think they apply?

Since it sounds like you have a lathe, buy a decent barrel blank like a 1:10 douglas and have some fun. I agree that keeping the shroud is a good plan, and you can make life a bit easier if you just make your replacment barrel a bit longer - and add a couple of wrench flats to tighten it with.

Once you get it apart, it will all fall together for you.

Thanks for having the integrity to fix this weapon, rather than sending a clunker on to a new owner.

B.

[Southern Son]

Jim,
Mate, In American Handgunner, January/February 2008 issue in the Pistolsmithing column Alex Hamilton talks about this. Your idea on the Allen wrench is his fix also. You asked what happens when you loosen the barrel, will the shroud just spin? Apparently there is a stud on the front of the frame that fits into a notch in the barrel shroud, so if you spin the shroud, you will shear off the studs. His fix was to machine off the studs and fit a barrel from a 681. The article is only short, one page, but if you have fitted a barrel to a revolver before, the only thing that has changed is getting the old barrel off and getting rid of the studs. Hope this helps.

Ron.
P.S. I hear what SuperMag is saying about you not creating the problem, but some time ago I bought a Parker Hale (the rip off of the 98 Mauser). It had been rebarreled to 308 Win. using an old fluted target barrel. The seller knew I lived far far away in a different state and so he told me the barrel on it was in good shape (not target accurate, but easily good enough to shoot feral pigs with, which is what I wanted). I was younger and knew very little about the inside of a rifle barrel. I can now look at the rifle and see that the barrel is a Maddco (very good Ozzy made barrel, I think as good as anything for anywhere else). But I can also see that it has been set back at least twice (I have a 22/250 Imp. barrel from Maddco and I have seen dozens of similar barrels from the same maker and I now know how they profile their barrel and where they start their fluting). I can see that the last chamber cut was not cut very well. And I can now see that the mongrel bastard ripped me off. If he had told me that the barrel was stuffed, I could have made an informed decision (is it worth rebarreling, how much would he drop the price, etc). I know the old saying buyer beware, but to just unload a dodgy gun on someone else because you can't be bothered to fix it and don't want to loose any money on it I think is a low act. Ahhh poo, I started ranting, didn't I?

[S.R.Custom]

...I hear what SuperMag is saying about you not creating the problem, but some time ago I bought a Parker Hale... I know the old saying buyer beware, but to just unload a dodgy gun on someone else because you can't be bothered to fix it and don't want to loose any money on it I think is a low act. ?

I hear what you're saying, and I agree with you, actually. But the two situations are quite different... in your case, you got dumped on by an owner with a worn-out project rifle. He bears the sole responsibility for the rifle's condition, and is thus ethically bound to make full disclosure on it.

In the case of PHX Jim's revolver, however, the ownership of the defect and the responsibility of correction lies solely with Smith & Wesson. Indeed, my recent experiences with S&W and observations of current quality at stores and gun shows indicates to me quite clearly that this level of quality is standard operating procedure with S&W these days.

That said, Jim doesn't bear responsibility for correcting the Smith's deficiencies any more than he would bear responsibility for smoothing out the action on a Charter Arms Bulldog or correcting the feed reliabilty of a Marlin model 60. It is what it is, and just because Jim is disappointed in the craftsmanship of the revolver, does not mean he is obligated to share that disappointment with the world. Let Smith & Wesson answer for the crap they produce. It's their name stamped on the side plate.

To wit:


Don't sweat the "crush" term in that assembly. S&W can't build a barrel tight enough for good accuracy, what makes you think they can make threads closer than a 2A fit?

Exactly. And S&W made a conscious decision to build to this level of quality for the sake of ease of manufacture and profitability. What about that makes it Jim's responsibility?

[JIMinPHX]

While its not exactly my responsibility, it is kind of my problem. I want a nice 4” K-frame & they just don’t make them any more, so my options are limited. I already sent it back to Smith & they did butkiss for me. As far as I know, I’m my own best second option to a factory repair. If I had a better option readily available, I’d take it. I don’t think that its fair for me to have to go through all this, but that seems to be reality for me to end up having what I want.

Smiths used to be my favorite handguns. Over the years I’ve bought several of them brand new. Unfortunately, that isn’t likely to happen again after this experience. It’s a shame. They used to be really good to deal with. They used to make a lot of nice stuff.

[JIMinPHX]

Southern Son,
Thanks for the tip-off. I’ll look around to see if I can find that article.

Bohica,
I don’t know if they can hold 2A class fit these days or not, even though it isn’t difficult with a good tap & a simple fixture to hold the tool straight, or a geo head or a split die. I was just hoping to hear from a few people that have actually pulled these things apart before, so that I could get some idea of how much this thing is likely to fight me when I have at it. So far, it sounds like 1 experienced person has weighed it. I was sort of hoping for 3 or 4, but pretty soon, I’ll take what info I have & take my best shot at it. I’ll let everyone know how it turns out.

Jim

[leftiye]

Jim, what specific barrel do you want? I have one off'n a Model 10-4, and another from a model 19-2 that I would feel no pain in parting with. Both 4" long, both pinned barrels. If you're interested.

FWIW, Brownell's sells both the dies and taps for the S&W K, L, N frames , with which you could correct the frame threads to fit the older style barrel (I'm guessing they're the same thread in the crush fit, just wrongly sized. - I could be wrong). Dies are about $80! Taps, maybe less, I can't remember, but you'd only need the tap.

[leftiye]

Jim, I didn't read all of that about the pitch diameter, so I don't know if you actually found out just what it is. My feeling is that on a 36 tpi thread there is almost nothing that you can stick in there to measure pitch diameter, and a comparator would therefore be the best and easiest way to go. Plus, unless you were to measure YOUR barrel shank (now on the gun), you might not actually know anything useful. Next, due to the crush (which I'm betting is another word for interference fit) fit you still might not know enough - even if you did measure your barrel. Normal K frame barrels screw on by hand until the last couple of turns. A tap as mentioned above should get you within reach of putting an older pinned barrel on, but an adjustable die may still be necessary to get it right. This is ONLY TRUE if the new barrel isn't smaller than the tap already!!!

[JIMinPHX]

Leftiye,
I don’t know quite what those two barrels look like off the top of my head. Would it be possible for you to post a picture of them?

I think that I’ll pass on the die. At $80 a pop, I don’t mind doing a little single pointing instead. Also, I’d rather reduce the barrel threads to fit the frame if needed rather than open up the frame so the tap is out too. Thank you for the info though. It’s always good to know that you have options.

I was also guessing that "crush fit" was their little code word for interference fit, which is why I started asking around about all this in the first place. The last thing that I want to do is gaul up a stainless to stainless interference fit by trying to take it apart without knowing what I’m getting myself into.

[leftiye]

Both my barrels are blued, so I guess not. The die would however make the frame "standard" if used, whereas it is most likely undersized as it is. Single pointing is the cheapest if you can manage it. Problem is that many cutting scenarios will not cut unless the cut is in the area of a .005" depth. They'll slide on the surface until the pressure is high enough, then dig in, so taking a thou may be some hard to do. Plus, with threads that fine the whole thread can be cut (new thread) in one pass. I'd perhaps try to "iron out" the threads with a reversed cutting tool to make them a thou or two deeper, if that was what was needed. I don't see you having much choice with that galling issue. You're going to have to unscrew the barrel - IF you are going to do it at all.

[shunka]

Bringing up an old (17 month?) thread to ask -
Jim what did you end up doing?

[Dave Berryhill]

I know that it's an old thread but I'll throw my 2 cents in. There isn't any need to gauge the threads on a new barrel. If the pitch is correct then use your frame as a gauge and just test fit the barrel until you cut the threads to the correct depth. You want a smooth, precise fit. You shouldn't have any wobble and you should be able to turn the barrel easily by hand until the shoulder touches the frame.

[leftiye]

It can be done, but if'n y'all cut too deep (get sum wobble) it's tuff tootsies (= all over). Best to measure going in, and make a cut to just over or right on the desired clearance. Threads will have some roughness, and will "wear in" some.

[machinisttx]

I think your on the right track! Lets see if we can't get those numbers for you before you unscrew anything.

I don't have a way to check pitch depth. I think you might need a "comparator" to do that with.

However I am going to suggest one of us PM Buckshot. I hear he's the wizard of such things and he might be able to shed some light on either the PD for the crush fit barrel or how to read the PD.

The other option is to try and figure out how to contact Jerry K. he may have info that never got into his current editon?

I believe Buckshot has a sticky posted in one of the other headings and from that he can be PM.

I am interested in what he has to say but I think you should do the PM as it's you who will sooner or later unscrew that barrel!

This way nothing gets lost in "translation"!

I do have the 6 inch barrel off the gun but not the 2 inch. If I don't get hit with a bout of the lazy's I will tackle that this week end.

Keep me posted.

You need a set of thread wires and a micrometer, or a thread micrometer. Either one can be purchased from www.use-enco.com

[Willbird]

Hi Lathesmith & thank you for that link. That was a good read.

Yes, this "hybrid" is the barrel with the shroud. I have not been able to find anyplace to buy the special bore wrench for grabbing the inside of the barrel, but I think that I have a pretty good game plan for getting around that one. I was planning on dropping a 1/4 long-arm Allen wrench down inside the barrel, then filling it with potting compound, like cerosafe or something. That should give me a good solid, well-distributed grip that is removable below 200 degrees F, so tempering should not be affected. Beyond that I was wondering what to expect.

Does that shroud just spin freely once the barrel is loose? Are there only the two parts? Or are there more? Is there someplace that I can get a diagram of the new style barrel? What kind of risk am I running by removing the original crush fit barrel? Will there be damage to the frame threads? Will I need to retap? Will I need to sleeve? Can I install a pinned barrel? Will the frame threads be too loose from already having a crush fit barrel installed & therefore make a pinned barrel difficult to attach rigidly?

I'm not trying to saddle you with all these questions Lathesmith. I'm just putting them out there for everyone to take a look at.

Thanks again for the reply.

Jim

Woods metal is what you want for that, it is alloyed to actually expand a tiny bit when it cools so it will grip tight, similar melting temps to cerrosafe.

Also MSC has a TON of oddball dies, for not a lot of money, with really fine threads it is often nice to have a die to run over them, and the dies MSC sells are split so you can adj them.

Be very very careful with a K frame frame, they bend easily, the George Nonte hammer handle in the cylinder opening trick will quickly bend a K frame.

Bill