Threading barrel tenon with a die?

john.k · Dec 13, 2022

Its actually a strange phenomenon ,how a threading die will cut to one side ....you would expect cutting forces to centralize the thread,but for some obscure reason they dont ,and the die cuts off the one side.........This problem was adressed in some of the older systems ,such as the "Little Giant" dies....in fact the GTD Little Giant die system was the best hand threading tool available ,ever .

wesg · Dec 13, 2022

No mystery. The lead-in exposes various widths of the teeth due to the helix of the thread. The fat side is going to push away and the narrow side will cut deeper. Once it's started....

Hence the idea of roughing it in on the lathe, even with a 16 TPI.

Geometric heads are pretty sweet for production work. But I'd think a large thread like this would require a pretty stout lathe to keep it true.

Best dies I've ever used are the acorn style. P&W maybe? I looked far and wide online some years back, and came to the conclusion they dont exist as a commercial item anymore. Bummer.

kendog · Dec 13, 2022

Another approach would be to run a 1"-16 tap in the receiver and chase out the metric thread to "Metperial". I did one quite a few years back, and fitted a take off Rem 700 police barrel to it. Wes's old neighbor Abe did the welding of the M14 magazine conversion pieces. Any Winchester push feed or Ruger barrel would lash right up to it with only a few modifications.
Shot quite well. Consistently under 1" with good bullets. Probably do much better with a Bartlein or Krieger.
As far as Amazon taps and dies... you get what you pay for.

1yesca · Dec 13, 2022

kendog said:
Another approach would be to run a 1"-16 tap in the receiver and chase out the metric thread to "Metperial". I did one quite a few years back, and fitted a take off Rem 700 police barrel to it. Wes's old neighbor Abe did the welding of the M14 magazine conversion pieces. Any Winchester push feed or Ruger barrel would lash right up to it with only a few modifications.
Shot quite well. Consistently under 1" with good bullets. Probably do much better with a Bartlein or Krieger.
As far as Amazon taps and dies... you get what you pay for.

NRDock · Dec 13, 2022

kendog said:
Another approach would be to run a 1"-16 tap in the receiver and chase out the metric thread to "Metperial". I did one quite a few years back, and fitted a take off Rem 700 police barrel to it. Wes's old neighbor Abe did the welding of the M14 magazine conversion pieces. Any Winchester push feed or Ruger barrel would lash right up to it with only a few modifications.
Shot quite well. Consistently under 1" with good bullets. Probably do much better with a Bartlein or Krieger.
As far as Amazon taps and dies... you get what you pay for.

Yeeeaaa, I'm not going to molest a perfectly good action when I have free barrels to experiment on.
I'll make a die holder with a concentric 1" diameter stub sticking out the back. This stub will be held in a collet in the tailstock. Position of the barrel tenon will be held with the steady rest. Since I have 1 3/4" of existing tenon and barrel to lose, I'll cut a long tapered lead concentric with the chamber to aid in getting the thread off to a good start. The wildcard is whether the die threads are even concentric to the OD of the die.
The MSC die is adjustable, so I'd start cutting an oversized thread, and then home in on a good fit to the action.

https://www.mscdirect.com/product/details/09036005

kendog · Dec 13, 2022

NRDock said:
Yeeeaaa, I'm not going to molest a perfectly good action when I have free barrels to experiment on.
I'll make a die holder with a concentric 1" diameter stub sticking out the back. This stub will be held in a collet in the tailstock. Position of the barrel tenon will be held with the steady rest. Since I have 1 3/4" of existing tenon and barrel to lose, I'll cut a long tapered lead concentric with the chamber to aid in getting the thread off to a good start. The wildcard is whether the die threads are even concentric to the OD of the die.
The MSC die is adjustable, so I'd start cutting an oversized thread, and then home in on a good fit to the action.

https://www.mscdirect.com/product/details/09036005

Molest it to what?? A dime-a-dozen action that you can now easily fit a barrel to when you dont have metric capability? And also stick on just about any Winchester, Ruger, or Tikka barrel you come across, or cut a new blank to 1"-16? With as good or better thread fit as most production guns out there.
More than one way to skin a cat.

wesg · Dec 13, 2022

kendog said:
Molest it to what?? A dime-a-dozen action that you can now easily fit a barrel to when you dont have metric capability? And also stick on just about any Winchester, Ruger, or Tikka barrel you come across, or cut a new blank to 1"-16? With as good or better thread fit as most production guns out there.
More than one way to skin a cat.

Abe?
Did you ever meet Wayne in Mt View?

Umm, yeah, so generally it's only the first 3 threads that take XX% of the load anyway. 'XX' being quite a bit more than 50%.

I kinda vaguely remember seeing/hearing a comment about something like this before. Good point to remember.

john.k · Dec 13, 2022

Unfortunately recutting inch thread to metric wont give 3% of initial engagement,and the thread will tear out in a wire .........its possible if you load up the threads with Loctite ,then sufficient strength will be there .........IIRC,backthrust of a standard rimless case is around 8 tons.....not a lot in engineering terms.....but if the pressure inside is released ,then things do go bad (or bang)

NRDock · Dec 13, 2022

After a couple years, I'll put this gun back the way I found it and sell it. When the next guy loads up his 308 with 45 grains of Red Dot and loses some body parts, his Lawyer won't be asking me about any bastardized action threads.

kendog · Dec 14, 2022

wesg said:
Abe?
Did you ever meet Wayne in Mt View?

Umm, yeah, so generally it's only the first 3 threads that take XX% of the load anyway. 'XX' being quite a bit more than 50%.

I kinda vaguely remember seeing/hearing a comment about something like this before. Good point to remember.

Abe was just about next door to your old shop, at least I thought it was your shop! Abe is Weld Tech, corner of Bay and Hurlingame. I still send him KTM 2 stroke exhaust flanges to weld up for me.

kendog · Dec 14, 2022

NRDock said:
After a couple years, I'll put this gun back the way I found it and sell it. When the next guy loads up his 308 with 45 grains of Red Dot and loses some body parts, his Lawyer won't be asking me about any bastardized action threads.

Hear that. 45 grains of red dot will take apart any receiver, no matter the thread. I know for a fact 23 grains of Accurate No 7 in a 7.62X39 will destroy a Mini Mauser.

john.k · Dec 14, 2022

According to Hatcher ,a Garand will take a case full of Bullseye as a proof load with pressure measured at 135,000 psi.and still function when the melted case and broken extractor are fixed.

kendog · Dec 14, 2022

kendog said:
Another approach would be to run a 1"-16 tap in the receiver and chase out the metric thread to "Metperial". I did one quite a few years back, and fitted a take off Rem 700 police barrel to it. Wes's old neighbor Abe did the welding of the M14 magazine conversion pieces. Any Winchester push feed or Ruger barrel would lash right up to it with only a few modifications.
Shot quite well. Consistently under 1" with good bullets. Probably do much better with a Bartlein or Krieger.
As far as Amazon taps and dies... you get what you pay for.

Well.. The memory is the second thing that goes. Can't remember the first...

I dug up my old records and it turns out I am full of crap! What we did was chase the Howa ring with a 1-16 tap and recut the tenon on a Rem barrel to 1.020-16. The fit was surprisingly good in the receiver and it is still going strong today. A 1-16 tenon would be a little too undersize for my comfort. Putting a Winchester barrel on there sounded good as I made it up while typing the post above. Guess I would make an outstanding politician, except my parents were married.

john.k · Dec 14, 2022

Yes ,a near enough thread can be double cut 10% or so larger ,but cutting 26mm back to 25.4 mm is just asking for trouble .....I once did a big project where I used 24mm nuts recut to 1" x 8.......saved thousands by using surplus 24mm nuts,and the substitution wasnt found out for 15 years ...when I was asked WTF?......even with the size difference in favour of the thread recut,it was still quite obvious that only one full thread and a couple of partials in the nuts..

wesg · Dec 14, 2022

kendog said:
Abe was just about next door to your old shop, at least I thought it was your shop! Abe is Weld Tech, corner of Bay and Hurlingame. I still send him KTM 2 stroke exhaust flanges to weld up for me.

Hmm, never heard of Weld Tech. I didn't get out much.

There's the 'gate guy' at the corner with Barron. 'Ornamental Iron' or something like that.

I took my TIG work to Mark at Alloy Cutting for awhile. Dirt bike connection. And more recently to JP in San Jose, another dirt bike comnection. Friends since the early 80's.

Wayne Werner, I think ... older Romanian guy that worked for us for a few years introduced me to him. Had 2 Shizouka/Bandits and 2 Mori lathes in a single car garage. He made the most beautiful octagon barrels. Integral ribs and sling swivels. And hinged floorplates for Mausers and M-70's. A real artist.

I've got no talent for that. Just dimensions and tolerances.

BT Fabrication · Dec 15, 2022

why not just outsource it to a good gunsmith?

1yesca · Dec 15, 2022

or a good machinist ! but that would cost money ! good point give ether one an old barrel or 6" length of bar stock and pay them to make a test and if your happy have them do the real deal and time it , chamber it and set the head space and your done

NRDock · Dec 15, 2022

BT Fabrication said:
why not just outsource it to a good gunsmith?

That's plan B. If plan A doesn't work out, I'll buy the 8 twist barrel I'd prefer, and have it professionally threaded.
I'm retired and this is a project. I have tools because I enjoy doing. The doing is nearly as important as the having.
I find it interesting that the range of replies is stacked at the extremes: Either it must be perfect Or go ahead and Bubba it.
A former boss used to claim that "Better was the enemy of good enough."
I intend to learn if a die and work piece held firmly in a real lathe can or can't achieve good enough.

BT Fabrication · Dec 16, 2022

NRDock said:
That's plan B. If plan A doesn't work out, I'll buy the 8 twist barrel I'd prefer, and have it professionally threaded.
I'm retired and this is a project. I have tools because I enjoy doing. The doing is nearly as important as the having.
I find it interesting that the range of replies is stacked at the extremes: Either it must be perfect Or go ahead and Bubba it.
A former boss used to claim that "Better was the enemy of good enough."
I intend to learn if a die and work piece held firmly in a real lathe can or can't achieve good enough.

id probably be willing to bet that it will thread on, all be it not very true or centered which is very important for any sort of gun barrel.
plus needing to use round dies(not the hex chasing dies) might be a bit of a challenge without a perfectly ridgid setup.
ideal is within tenths of an inch of parallel to the bore, centered to the bore and to size etc.
dies might be a thou or so which might be ok on a shotgun or a full floating bolt head design.

Threading barrel tenon with a die?

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