So here's the story. I have an unusual barrel that I can't easily replace, a 10mm conversion barrel for a USP40. The threads were clean, 14.5x1LH, but only have of the threaded devices I have will thread on easily, those two being the factory HK thread protector off my USP40 tactical, and some aftermarket Glock protector. I have two Griffin Cam-lok adapters and two thread protectors I got off HKParts that won't cooperate. And in one attempts, I think I may have buggered up the start on the barrel, as the caps that were working smoothly are now a bit rough. The barrel maker hasn't responded to my inquiries.

Is there somebody here, or somebody that somebody knows, that can possibly clean up the threads? I would very much like to be able to use my Cam-Lok suppressor on this 10mm USP I've got.

Metric taps and dies are available at CNC Warrior:

https://www.cncwarrior.com/category-s/1513.htm

Unfortunately, I can't find a 14.5x1 LH die. 15x1 RH, 14x1 RH and LH, but no 14.5

Tom Ryder at SPR Industries is your best bet in the north end. He does excellent work if you’re willing to wait. He was a bit booked up last time I checked.

Yeah, i looked around online and couldn't find one either.



This might be your best best. I'm sure he could cut/cleanup those threads for you.

I use needle files to chase buggered threads on male threads.

You should be able to find a good set at Lowes or Home Depot.

Needle or jewelers files. There are also thread files. They are square with multiple pitches and are handy for the rest of your life.

Funny you both should say that...

I just did a few minutes of this very thing with a triangular file out of a Home Depot set, looking for rough spots in the thread valleys and trying to reform the crests. Not 100% sure where the problem was, but it seems to have worked. Threads are still a bit off, as they always were, some of my caps still won't thread on, but I can put my Cam-lok device on now if I use a socket wrench and some gusto. It felt like it was cross-threading at first, but it isn't. It's just very tight.

Phone call to McMaster-Carr and they will get you the tap/dies needed. Never have I ever failed to get an item needed that was not listed on their catalog by simply calling.

Get a split die so you can adjust the pitch diameter(so it doesnt cut too much or too little), or a thread file.

I dont have power to it yet(dont need power though) but i could rethread it by hand on my new lathe, i'm a 20 year machinist and toolmaker, so it'd be easy. I'm in sultan

I usually just cut threads like this in the lathe, but my suggestion, and this is better than using a die for what you have - buy a thread protector that fits, apply a small amount of fine valve lapping compound to your barrel threads, and gently work the thread protector back and forth. Clean and check often until you can just thread your tightest muzzle device on the barrel.

This method won't take off more than you need, and it won't result in any undersized spots along the thread like a die can when it goes crooked. It will wear the female thread at about the same rate as the male thread, hence the reason for doing it with a thread protector rather than one of your muzzle devices.

This also results in a smoother thread than using a die.

I've had some luck cleaning up threads but cutting a nut in half

Clamp the threaded part in between the two halves in a vice then back the part out

A 14.5x1 left hand nut is not a common item at McLendon so YMMV