Anyone know who could cut internal threads like this…It's finished, See Pics..

[ARCHIVED THREAD] - Anyone know who could cut internal threads like this…It's finished, See Pics..

Posted: 2/22/2021 11:02:22 PM EDT

Anyone know who could make a steel sleeve with 1 1/4-18 internal threads as shown below?
The sleeve would be used to replace a factory barrel nut on a special build. (see pic #2)
Any contact information or personal recommendations on who could execute this?

Posted: 2/22/2021 11:37:31 PM EDT

[#1]

I could do it.

Posted: 2/22/2021 11:43:57 PM EDT

[#2]

Anybody with a lathe and a couple measuring apparatuses. Maybe depending on what class of threads and fitment and how tight you want your tolerances it'll narrow down the field.

Posted: 2/23/2021 12:13:19 AM EDT

[#3]

A barrel nut that has a wall thickness of ~ 0.040"? That is pretty thin. Out of curiosity, if this is replacing the barrel nut, how would it interface with the barrel flange?

Posted: 2/23/2021 3:32:53 AM EDT

[#4]

1.330 - 1.250 = 0.080
Eighty thousandths of which part is cut as threads doesn’t leave much material for strength. Might be better to enlarge the interior diameter of the Trunion. Or make the first 1/2 or 1/3 inch the same OD as the Trunion and then step down to fit the Trunion. You probably don’t need the internal threads to go more than 1/2 or 1/3 inch after which it can likely be smaller than 1.250 ID like 1.10

Posted: 2/23/2021 9:03:03 AM EDT

[#5]

The thin wall makes is a bit more challenging. The way I'd do it would be to bore and thread a thick wall tube, then put that on a threaded fixture that I single point cut in a lathe, and which I'd leave in the lathe. Then turn the O.D. down to size. However, as noted above that thin wall may want to crush when the trunnion is tightened. But, that may not be all that bad of a thing for it would make a tighter fit on the threads.

Posted: 2/23/2021 12:17:49 PM EDT

[#6]

Here's his other thread for context -

https://www.ar15.com/forums/precision-rifles/Anyone-know-who-could-cut-external-threads-like-this-see-pic-/8-11141/

Posted: 2/23/2021 12:50:43 PM EDT

[#7]

Quote History

Quoted:
Here's his other thread for context -

https://www.ar15.com/forums/precision-rifles/Anyone-know-who-could-cut-external-threads-like-this-see-pic-/8-11141/

View Quote

Well that changes everything. Thanks for providing the context.

Posted: 2/23/2021 1:32:27 PM EDT

[#8]

Quote History

Quoted:
1.330 - 1.250 = 0.080
Eighty thousandths of which part is cut as threads doesn’t leave much material for strength. Might be better to enlarge the interior diameter of the Trunion. Or make the first 1/2 or 1/3 inch the same OD as the Trunion and then step down to fit the Trunion. You probably don’t need the internal threads to go more than 1/2 or 1/3 inch after which it can likely be smaller than 1.250 ID like 1.10

View Quote

You forgot to divide by 2 for the wall on both sides. The wall will be .040 thick when bored.

@MR_JOSHUA you only have .040 to work with and the threads are going to cut in ~.036 or so. You have no material left. You are going to have to open up the trunnion.

Posted: 2/23/2021 3:40:04 PM EDT

[#9]

I understand what you are saying but the factory barrel nut is exactly like you mentioned (not much material).
See item marked #1 in the first set of pictures. Not much wall thickness, but it works.
Yes, I'm surprised the company (Coda) is making a barrel nut that thin.

Posted: 2/23/2021 4:07:47 PM EDT

[#10]

Quote History

Quoted:
I understand what you are saying but the factory barrel nut is exactly like you mentioned (not much material).
See item marked #1 in the first set of pictures. Not much wall thickness, but it works.
Yes, I'm surprised the company (Coda) is making a barrel nut that thin.

View Quote

with 3 or 4 thousands holding the threads together (about the thickness of a piece of paper) you essentially have a thread filler and are relying on the clamping force of the trunnion to do all the work. Hate to say it, but you might have been better off just using a split sleeve and saved yourself the hassle of all the threading ops. I guess you still could, the threads would just provide some gription for the sleeve. I don't know. Interesting project anyway. Share pics of the final.

Posted: 2/23/2021 8:52:57 PM EDT

[#11]

I have to believe 1mm wall thickness is good.
Don't get me wrong, it doesn't have much integrity by itself, but once installed and clamped inside the trunnion, it's solid.

Posted: 2/24/2021 1:29:17 AM EDT

[#12]

Quoted:

You forgot to divide by 2 for the wall on both sides. The wall will be .040 thick when bored.

@MR_JOSHUA you only have .040 to work with and the threads are going to cut in ~.036 or so. You have no material left. You are going to have to open up the trunnion.

View Quote

That's not the way it works.

1.25 is the max major diameter of the thread, that's measured at the root of the internal thread. So he has a full 0.0415" or more on each side. There are suppressors with screw-in end caps that have less "wall" than that. For his intended purpose there are no concerns.

Let's get on to the purpose of the OP.

Any moderately capable machinist or machine shop should be able to make it.

Posted: 2/24/2021 1:47:20 AM EDT

[#13]

Might I suggest you take a stock barrel nut and just chuck it up in the lathe and turn the outside.

Looking at your design, i believe the handguard will walk of the nut under recoil. it would be best to have a groove around the nut that is mated to an internal ridge in the trunion mount and make it split.

Posted: 2/24/2021 1:53:08 AM EDT

[#14]

Anyone with a lathe who knows how to do use it.

Why stainless, though?
You should aim to match materials, where possible. I’d recommend 7075... inexpensive and machines like a hot knife through butter.

Secondly, why attach a tubular handguard to a bolt action’s barrel, of all places. I would think you want nothing touching the barrel... like ever.

Posted: 2/24/2021 9:43:54 AM EDT

[#15]

Quote History

Quoted:

That's not the way it works.

1.25 is the max major diameter of the thread, that's measured at the root of the internal thread. So he has a full 0.0415" or more on each side. There are suppressors with screw-in end caps that have less "wall" than that. For his intended purpose there are no concerns.

Let's get on to the purpose of the OP.

Any moderately capable machinist or machine shop should be able to make it.

View Quote

Well shit. I hate being wrong, but I am. I'll be in the corner.

Posted: 4/9/2021 11:43:07 PM EDT

[#16]

Finally got this finished.
Pictured below are detailed pics.
This went together very well.
All the threading was done by pro’s.
The guy who made the sleeve and machined the barrel nut did a fantastic job (thanks Eric)
Can’t emphasize how happy I am with this build.
The Coda handguard is extremely rigid, as expected with carbon fiber.
I’m obsessed with iron sights, but it was a pain finding front & rear rails that would
allow the sights to line-up correctly (rails not equal in height from C/L of bore).
That was a challenge:

[ARCHIVED THREAD] - Anyone know who could cut internal threads like this…It's finished, See Pics..

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