Need a 1/2-28 external thread .625 deep on one part

[Paraquat]

I used to work in an aerospace machine shop where we could use the machines for side projects on the weekend (as long as we paid for our own material).
I no longer have that job so I no longer have access to the machines.
I have a cutesy Harbor Freight Lathe in my garage but it's not nearly large enough for this part.

The part is a .22LR barrel for an AR15 upper. It's a gunshow-quality garbage barrel. Instead of threading the end 1/2-28 for an A2 style flash suppressor the mfg left it 1/2" diameter and slipped on a hideous flash supressor.

I have broken it down to just the barrel to make it easy to send out. It's probably gonna have to be a 3 jaw. The OAL is 16.25" with a major diameter of 1.177" at the heaviest point.

It looks like they used the same outside turn profile for this barrel that is used on a .223 barrel so the diameter I desire to be threaded is already chamfered, .4985 diameter and relieved.

The last time that I did this myself I greased up a gage pin, slid it into the ID, indicated the gage pin, skinned the diameter, shoulder and threaded it. The external threads must be concentric to the ID. No surface finish is required. No coating is necessary. I can supply a 1/2-28 tap and the flash supressor that I want if dimensions are desired but as long as it threads on it's good enough for me.

If you're second amendment friendly you already know this but I'll write this for everyone else who's shaking in their boots:
I am not making this gun any more or less deadly.
I am not altering the over all length.
I am not doing anything considered "illegal" by the ATF or local laws.
This is just a bare barrel and alone is considered a part and not a "gun". Only the lower receiver is considered a "gun".
This barrel came with a flash supressor that was not permanently attached and will be replaced with a flash supressor that is also not permanently attached. Only cosmetically different and mounted differently.


The lower barrel is the one I desire to be threaded.


Skin as little as possible off the diameter and shoulder and thread it. Please do NOT face off the front as it could roll material over the rifling of the barrel. Should be cake?
Now the difference between a .223 and .22LR is a couple thou but this barrel is properly rifled for a .22LR and is mounted differently than a .223 barrel is. The point of this is I'd have to buy a new barrel if it was junked and it's kind of specific and would probably be a pain to replace and please try not to scratch it up.

[abcmojave]

Don't know alot about guns but it sounds like a through-the-headstock threading job. If so, what is the diameter of the barrel that needs to feed through? Like the first 10 inches or so?

Also wouldn't you use a four jaw? So you could adjust after indicating?

[Paraquat]

Got one message asking me to clarify:


Depending on how "old school" you are the tap was just meant for reference incase you wanted a pitch diameter. As long as the flash hider threads on I don't really care. It's just cosmetics for me.

What I want is a ~.218- gauge pin (maybe .217- because it's a brand new barrel) greased up and shoved in the end. Indicate off the pin and skin as little as possible off the OD and shoulder (just to 100% ensure concentricty) and thread.

The end game is I just want to use a different flash hider.



The barrel is a lot of different diameters. Most everything is or is +/-.002 from standard dimensions. I grabbed my verniers and drew it out in Autocad real quick so I can avoid any further confusion from my sloppy descriptions.

[Paraquat]

Forgot the attachment.

[Paraquat]

Got 'er done locally.
I was able to drop it off at a local shop on Friday and pick it up Monday.
I do appreciate the quotes I received and I hope that there are no hard feelings that I kept it local.

I'll leave the drawing up there if anyone wants it. It's for a Chiappa .22LR dedicated upper barrel if this job ever presents itself to anyone on this forum.

[Bob La Londe]

Cool. I read through this and was about to suggest you just find any decent lathe operator to do it for you, when I saw your reply that you had gotten it done. Sounded like a pretty straight forward job. I do want to comment that I found the bore for my little lathe to be inadequate, and I sacrificed the tapered spindle in favor of boring it out to a larger size. Of course by the time I actually needed the larger size again I had bought a slightly bigger lathe. LOL.