Threaded Suppressor Adapter

[xr650rRider]

Got a link to anything about that? I can't imagine a simple thread adapter (which may, or may not, be used with a can) being regulated.

GsT

https://www.atf.gov/firearms/firear...on-firearms-national-firearms-act-definitions

The adapter itself might not be until it is used in conjunction with a muffling device. Be it an oil filter, solvent trap or an actual suppressor. You can no longer get a form 1 approved unless you have an 07-FFL and a manufacturing license, so for the average Joe, making an adapter for a suppressor is considered manufacturing parts of a suppressor. Probably should contact an attorney.

 

[wnchstrtnfldvlle]

Where did you see that about the form 1 and "Unlicensed Persons" no longer being able to submit? The only thing I could find is where you can no longer purchase the "parts" to make the suppressor after submitting the form 1. It looks like the entire thing needs to be made from scratch. Not even sure about that one though.

 

[xr650rRider]

It's been going on for > 2 years. I haven't seen anyone that has had a form 1 approved since then. Seems they usually get a letter saying they are already in possession of illegal parts that constitute a suppressor. If you can prove you produced your raw materials when you submit your drawings, then maybe you'll be legal. I'm not the suppressor police and you might not ever be prosecuted. It all comes down to what is your freedom worth?

 

[wnchstrtnfldvlle]

I see what you're saying. They're working in the gray area to keep it from happening.

 

[GeneT45]

Understood. It's more to just practice hitting dimensions. The overall goal is to start chambering my own barrels, so I thought this would be a good project to start practicing.

When I cut a thread shank for barreling I do it just like a regular pre-finishing cut and leave some extra. Then measure the spigot length with a depth mic and cut to a true length. As it turns out though, even that doesn't need to be extremely close to nominal, because you'll be measuring headspace with that barrel and its intended bolt or receiver.

GsT

 

[wnchstrtnfldvlle]

Made some progress.

1. Third time's a charm. 1.125-28 threads completed. Suppressor threads on with almost no play at all.


2. Initially drilled out the bore to get a large enough hole for the small boring bar.


3. I used the small boring bar to get a concentric hole for the final tap sized drill to follow in an effort keep it from wandering. Got the idea from a Joe Pie video where he shows how to drill deep small diameter holes straight. I just did it without the reamer step. Was trying to keep maximum concentricity. Maybe it wasn't necessary, but I'd hate to have a baffle strike or shoot the can off.


4. Next was the small boring bar again to start the large bore where the spring rests. It was .930 in diameter, and .420 deep. Followed by the larger boring bar once the hole was big enough. Roughing passes were about .020 away from final dimensions. Then I took the boring bar to .420 deep, cranked the cross slide out to .930, the hit the feed (away from the chuck) to finish out the bore. 3 tenths off. Pretty proud of that.


5. Parted off and set next to the original adapter. I think my chamfers were smaller that the original which makes it look a little larger.


I ordered a 1/2-28 UNEF tap from McMaster-Carr which will arrive Monday. I will probably just use the new dividing head to hold to the adapter while I create the hex wrench flats, then mount it on the mill the thread the 1/2-28. That gives me a chance to use a new tool, and is less work than threading a mandrel or any other way of mounting it in the lathe to thread.

Advice and constructive criticism welcome. Thanks for looking.

 

[bbaedke]

Well, got the lathe back up and running and was looking for a project to start on that would test my abilities to follow a set of drawings. Then the other night we discovered an armadillo den between the neighbor's house and ours. Which made me think about suppressing my Mk4. I don't have a .22LR suppressor, but I do have an Omega 9K that accepts a threaded adapter. The only really critical dimensions are the threads. 1/2-28 UNEF for the muzzle, and 1.125-28 UNF for the suppressor side. But I did measure out the original 5/8-24 adapter to use for the drawings. Aluminum rod for the practice round, then either 4140 or 416 stainless for the final part. I haven't even started trying to figure out which would be the better option so any advice would be appreciated.

Preliminary design stuff
View attachment 510394

I'm also trying to get better at CAD, so here is the attempt. I did have to look up a couple things, but the majority I was able to remember how to do.
View attachment 510395

Chucked up in the lathe and turned to the 1.200" overall diameter. As you can see that is steel. I attempted to thread away from the chuck without rewatching the Joe Pie video, and ended up cutting left-handed threads, lol. So now it's a restart with the 4140.
View attachment 510396

A couple questions.

1. What strategy do you guys use when setting up to hit the Y-axis dimensions? Do you face it then mark that the zero, then watch the DRO while traveling towards the chuck to hit the mark? Or would you work your way backwards from the 1.2" ring turning to the major diameter and then face off before starting the 1.125-28 threads?

2. How do I get the threading insert (or HSS tool) to reach the centerline for threading? Pic below for clarity, but there's no way that I can see to get the insert at the proper level. I run out of travel way before. In the Joe Pie video, it looks like he has a shop made adapter that allows for higher placement on the tool post. Any ideas?
View attachment 510399

You can raise the quick change tool holder up, put a small spacer under the knurled nut, then drop it down and adjust the nut to put the cutting edge on center. Keep the spacer with that holder and it just takes a few seconds to drop it in each time.