How would you rethread this part?

[John TV]

So my son In law asked me if I had some taps. A few I said, what size? Half an inch by 36 tpi he said. No don't have that size, what's it for. Re threading a flash hider he said. A gun part. It currently has half inch by 28 tpi.

So he goes and gets the part and I see it is a no go for me. I am way to new to this hobby and way to inexperienced to do work on gun parts but it did get me thinking. How could you do this?

I know a very little about machining and even less about guns but hypothetically it's fun to think how I might do this rethreading. I will post a pic of the part so you can see the hypothetical work.

In my newbie thought process I can think of two ways that might work. One,bore out existing threads, put in a sleeve and rethread. Or second, maybe fill the threads with mig or tig weld then drill, bore and rethread. But I don't pretend to know what kind of metal ( most likely steel but what). Or the pressures this part will take or if a sleeve would even hold.

But I thought it might be fun to throw it out to you all to help me learn what options you might use or if it possible at all. Thanks for your thoughts and helping me learn.


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[Robert LaLonde]

I'd probably single point it on the lathe if it would mount easy in a chuck. If not then I'd single point (multi flute) thread mill it on the KMB1.

 

[pdentrem]

Well, there will be some pressure on this part. Best way is get one with the correct thread. Second best is to machine to a larger size and insert a threaded sleeve that is also threaded on the inside with the wanted thread and held with thread locker.

 

[derf]

I've never seen a muzzle threaded 1/2 x 36......what rifle is it?

 

[3strucking]

its common for 9mm to be threaded 1/2x36

 

[John TV]

I'd probably single point it on the lathe if it would mount easy in a chuck. If not then I'd single point (multi flute) thread mill it on the KMB1.

So already learning. Googled kmb1. What would you do to replace the existing threads since both are 1/2 inch. Would you fill existing cavity or is there another way to add metal to allow rethreading?


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[3strucking]

make a adapter that is short as possible. thread female end 1/2x28 and male 1/2x36.

 

[magicniner]

Bore it, thread it, sleeve it thread-locked, thread it.

 

[Billh50]

I would bore it for a larger thread and make an adapter sleeve. Then thread lock the adapter in. or possibly use a dutchman to keep the adapter from unscrewing.

 

[Robert LaLonde]

I would bore it for a larger thread and make an adapter sleeve. Then thread lock the adapter in. or possibly use a dutchman to keep the adapter from unscrewing.

Bore it, thread it, sleeve it thread-locked, thread it.

Leave it to me to overlook the obvious issue and get into the fun parts. LOL. Yeah, I think I would go for the same solution as others. I'd make sure to use a steel that will accept blackening nicely, unless I wanted it to stand out. If I wanted it to stand out I'd probably use 416 stainless for its strength and easy (relatively) machinability. Sometimes its easier to make a contrasting part look good than to make a matching part look good.

One thing nobody asked. Is it necessary for the part to index? That adds a level of difficulty unless you index it with a stop nut (ring).