Smith and Wesson third model double action 38

[ajjohns]

I've posted on this before and thought I'd post again because it's been a long time and made some progress. I bought a new barrel for my Third Model double action 38 from Numrich awhile ago. From what I've read, trying to find info on this seems hard, others have too. The description says that the barrels were in the white and needed a forcing cone cut in them. Mine had forcing cone and crown done. The problem was they had no base pin, so you need to provide one. I could do that. Where it got funny was no one seemed to know how this base pin came out of an existing barrel. Threaded, pressed? At least mine (maybe all) is threaded. I made a square piece out of aluminum with the right size hole drilled in it and made a slit through it as so it would clamp on the base pin tight in a vise. Heated the barrel up a bit and tapped on it with a rubber mallet counter clockwise, and, it threaded out. But, as near as I can tell by micrometer and magnifying glass it is .356 diameter and a 54 tpi cut. Very fine work. Now, the new barrel has no threads tapped into them for this, but is drilled to a proper or close tap drill size hole. Threads are the part that needs the work. I've looked high and low, Brownells, custom, no avail for a tap. Does anyone know of such a thing? 9mm x .5 is close, but not quite. I find 5/16 x 56, 11/32 x 32, and 3/8 x 56. Also close but won't do. Any help is appreciated.

Thanks, Aaron.

[deltaenterprizes]

Do you have a lathe?
I don’t see much thread left on there.
If you have access to a lathe I would use a piece of scrap and turn and thread to the dimensions you described and see if it will fit.
Another thing to try is making a casting of the hole and getting measurements from it.

[ajjohns]

I can use a lathe. The threads look wore because they're so fine. That was going to be my next thing to do, is to try and make a tap. I'll make a thread first and try it, then convert the threaded piece over to a tap by cutting chip grooves and hardening it. Am going to try it on a predrilled hole in some scrap and see if it works.

[deltaenterprizes]

I can use a lathe. The threads look wore because they're so fine. That was going to be my next thing to do, is to try and make a tap. I'll make a thread first and try it, then convert the threaded piece over to a tap by cutting chip grooves and hardening it. Am going to try it on a predrilled hole in some scrap and see if it works.

Sounds like a good plan, I hope it works well for you!

[ajjohns]

Well making a tap didn't work out so good. The thread is so fine, cutting the chip grooves in it didn't make it sharp enough. And after hardening it just wouldn't cut. So, I decided to turn the base pin down to fit the hole, Loctite, and press in. That worked out fine.
Another thing is the square hole in the top of the barrel for the barrel latch and cam was also not finished. It was wide enough, just not tall enough. Elbow grease and a small square file got me close, I filed on the other parts to make it all fit. Maybe was getting impatient but it all fit and went back together. Cold blued the barrel, added my modified J-frame grips and test fired it with my handloads. It worked great and everything on this gun now, is nice and tight. The pivot, the latch, cylinder, it all is like new or better. Keep in mind this doesn't allow me to load any hotter, but it should be better. Plus this barrel has a taller front sight so I can tune it in if needed. The original shot much too high.
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