Left hand threads question

egraham

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I was screwing the can on my Sig 226 this morning and thought about the origin of left hand threads. The only guns I have with LH threads are European.

is there any particular reason or advantages to being LH on suppressors?

I know that on weed eaters, circular saws, etc they serve a purpose but can’t understand why they would be better on a gun.

thanks.
 

epoletna

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Did I miss something in that article? I didn't see anything that said why LH threads are preferable. It did make a good case for the larger diameter of the 13.5 mm thread diameter, but no statement about left versus right. Or did I miss it?
 

LeftyJason

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Did I miss something in that article? I didn't see anything that said why LH threads are preferable. It did make a good case for the larger diameter of the 13.5 mm thread diameter, but no statement about left versus right. Or did I miss it?
I don't think there is anything inherent about left hand vs right hand. The important factors is what goes along with the thread.

If you had this thread and changed it to a right hand thread it would work the same.
factory-glock-17.jpg

There are different ways of making threads "better". Having the relief at the back vs not makes it easier to machine (especially manual lathes) and have square shoulders. Don't go too small.
No reliefimages.jpeg
Reliefbarrel-thread-1-copy.png

For consistency of cutting threads, using a "topping"or full profile insert is great. It already has the proper radiuses built in if you order the right one. If they are using cnc most likely in use already. Downside is you have to have one for each thread pitch (eg -28, -24,-18, or x1)
ISCAR_THREAD_Full-Profile.png

For easier starting / stronger threads go lower pitch. Having a area in front that is a cylinder also helps start straight but has to be designed in to work. Also chamfer the front thread.

One thing that is used in oil and gas is known as a higbee thread or blunt start thread. Not needed in guns and a pain in the butt to cut. (CNC thread cut with a square groover the first thread on both ID and OD threads. Has to have consistent timing.)
HigbeeCutCloseup.jpghigbee_results.jpg
 
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egraham

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Thanks. The only thing I don’t like is when you grab the suppressor to tighten down on the gun, the suppressor tube unscrews sometimes because those are right hand threads.
 

LeftyJason

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I understand. I run a grinder at work and I sometimes grind threads. Most are right handed and some are left handed. You have to check every one with ring gages.
 

paco ramirez

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Thanks. The only thing I don’t like is when you grab the suppressor to tighten down on the gun, the suppressor tube unscrews sometimes because those are right hand threads.
Grab the piston housing instead of grabbing the tube when tightening it down. Since the piston cage should be locked into the piston housing it shouldn't unscrew no matter which way you turn it. Unless you're using something like an Octane or Tirant or similar where OD is 90-99% tube.
 

egraham

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Tirant 9 has a left hand threaded piston for my sig 226.

my octane stats on my Suomi which is 1/2 -28 so no issues there.

I just cleaned both cans. Octane is way easier to clean. Dump all the baffles, piston, fixed barrel spacer in a tumbler with stainless pins before work and when you get home dry off baffles and put back together