Thread adapters: Why the hate?

[86indy]

I have trust issues working in the manufacturing world I just opted to skip adapters. Less variables the better, it’s that simple for me.


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[Firth]

I left the 6.5 CM at 22” long because I have the ZG 6.5 and OG 6.5 I can use with it. I knew from using my little gauge, that it would be 1/2x28 and I was okay with that. I also had already ordered a good (UM) 1/2x28 to 5/8x24 adapter for it.

As far as I know, Kampfeld (that’s the name I couldn’t remember) is the only trustworthy smith who does them collared like that.

Shooter71 on here has done a couple for me. They came out great.

 

[Kurts86]

I was worried until I used a few and now I’m fine with them assuming you check alignment.

 

[Jimbee]

Anyone have the thread adapters that caused them issues lying around?

I’ll pay shipping costs if you want to send them my way.

I had a cheapo thread adapter that made my supressor crooked enough to take a little hunk out of the end cap. I can see if I still have it. It was obvious after I pulled the bolt and just looked down the bore through the supressor. You're welcome to it but why are you wanting adapters that caused issues?

 

[WoodlandCritter]

I'm clearly one of the guys you're complaining about. I have had baffle strikes with thread adapters and have avoided baffle strikes because I've checked the alignment of other adapters before using them. My background is in manufacturing with a focus on precision CNC machining. Put simply, I do not trust the average lathe operator to even be able to read GD&T callouts in the US anymore. I use adapters when necessary, but tolerance stack is real.

Lets look at some numbers. Its pretty average to see a suppressor be 0.060" overbore. Than gives you 0.030" of clearance per side. If the shoulder of your barrel is perpendicular to the bore with a max error of ~0.2 degrees, that gives you an additional error of only ~0.1 degrees with an 8" can before you get an endcap strike (feel free to check my trig). Of course that's assuming you get very unlucky and the high spot of the adapter clocks perfectly with the high spot of your shoulder. But its possible, and cans are expensive and difficult to buy. So do I want to rely on some guy making 13$ an hour to make sure he's using a fresh insert when he makes my adapter? Nah. Not really.

 

[Shortschaf]

I'm clearly one of the guys you're complaining about. I have had baffle strikes with thread adapters and have avoided baffle strikes because I've checked the alignment of other adapters before using them. My background is in manufacturing with a focus on precision CNC machining. Put simply, I do not trust the average lathe operator to even be able to read GD&T callouts in the US anymore. I use adapters when necessary, but tolerance stack is real.

Lets look at some numbers. Its pretty average to see a suppressor be 0.060" overbore. Than gives you 0.030" of clearance per side. If the shoulder of your barrel is perpendicular to the bore with a max error of ~0.2 degrees, that gives you an additional error of only ~0.1 degrees with an 8" can before you get an endcap strike (feel free to check my trig). Of course that's assuming you get very unlucky and the high spot of the adapter clocks perfectly with the high spot of your shoulder. But its possible, and cans are expensive and difficult to buy. So do I want to rely on some guy making 13$ an hour to make sure he's using a fresh insert when he makes my adapter? Nah. Not really.

How could you possibly get the rearward shoulder out of square with the threads, or the internal threads non-concentric with the external threads on a CNC lathe?

Isn't it all done in one operation?

Genuine questions from a manual lathe novice. Curious how we end up with bad adapters

 

[WRO]

I have trust issues working in the manufacturing world I just opted to skip adapters. Less variables the better, it’s that simple for me.


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Barrell threads can be mismatched as well.

 

[Marbles]

Check alignment by looking down the barrel and out the muffler.

Do it regardless of adapter or not.

It is easy.

Barrel threads can be off. Suppressor threads can be off.

Good adapters are less than $30. https://precisionarmament.com/m4-muzzle-thread-adapter/

If you have an OTB can then get the Unknown Suppressors adapter.

 

[Pookie]

Many people use thread adapters. I use a thread adapter on 5.56 to run my 7.62 can. As with any new setup for a can, you should check to make sure it's aligned through the entire barrel and can path.

 

[WoodlandCritter]

How could you possibly get the rearward shoulder out of square with the threads, or the internal threads non-concentric with the external threads on a CNC lathe?

Isn't it all done in one operation?

Genuine questions from a manual lathe novice. Curious how we end up with bad adapters

Good question although not necessarily the right one. The issue is alignment to the bore, not the threads. When a barrel is drilled with a gun drill, the drill will wander a bit. So the bore isn't always perfectly aligned with the outer diameter of the barrel. And, of course, the OD is generally what you're holding in the chuck.

Therefore, both your shoulder AND threads can potentially be misaligned to the bore even though they're cut in the same setup. You gotta get used to really considering what your primary datum is.

Then as far as the adapter goes, there's a whole host of ways you could mess that up between changing setups and changing tools.

 

[North of 60]

It is simple (not hate)...adapters are unnecessary when it is so easy to get 5/8 x24 threads on a barrel and thus no need to fool with an adapter.

 

[nm.otter]

That's what a proper threaded shoulder nut does: Index on the bore center, thread deep enough with a relief cut to allow the shoulder adapter to seat, Rocksett the nut in place, and bead blast the outside to match the barrel finish.

 

[Shortschaf]

Good question although not necessarily the right one. The issue is alignment to the bore, not the threads. When a barrel is drilled with a gun drill, the drill will wander a bit. So the bore isn't always perfectly aligned with the outer diameter of the barrel. And, of course, the OD is generally what you're holding in the chuck.

Therefore, both your shoulder AND threads can potentially be misaligned to the bore even though they're cut in the same setup. You gotta get used to really considering what your primary datum is.

Then as far as the adapter goes, there's a whole host of ways you could mess that up between changing setups and changing tools.

I guess, my question presumes a gunsmith who put threads concentric to the bore.
I am aware of the inadequate precision of boring a rifle.
That is why I am curious---the precision of making adapters should far exceed that of the bore drillers.
And provided the gunsmith threads the muzzle to the bore, I guess you sort of answered my question with the "setups and changing tools" comment

 

[elkivory]

It is simple (not hate)...adapters are unnecessary when it is so easy to get 5/8 x24 threads on a barrel and thus no need to fool with an adapter.

Maybe I'm missing something here, but there are guns that the barrel is too small to do a 5/8. I have a browning x bolt 300 Win Mag with a 26" barrel that the outside diameter is under 5/8. I just had it cut to 22" and threaded 1/2x28. I will be using an adapter. I know there are suppressors with 1/2 hubs, but I want to go 5/8 so I can put on other guns.

 

[Nine Banger]

I have one adapter stuck in a can, installed by UM. It's not a big deal, it doesn't affect the can or shooting other than being dedicated to that rifle becasue its the only one I have with 1/2" threads, but if I were to do it again, I would use the other style of UM's adapter that uses their special tool so I could remove it.

I got one of the old style UM adapters out of a raptor with blue loctite.

Made my day.

Those things have nothing to grab onto to get them off a barrel either to switch to OG. Had to order a pack of 5/8x24 nuts and wail on it. In hindsight I should have ground flats on it.

 

[vonb]

I'm leery of tolerance stacking. However, the first thing I did when buying cans was buy some alignment rods. Cheap insurance.

I bought two adapters, one a Silencer Central and the other a GrovTec. The GrovTec introduced concentricity issues as seen with the alignment rods. The Silencer Central adapter did not. I used that one and Rocksett it in place. I'd prefer straight 5/8-24 but also want all the velocity I can get from this factory rifle and don't want to cut the barrel down.

Lastly, I don't see adapters as creating any more stacking than muzzle devices such as Plan B mounts. Gotta check it all.

 

[North of 60]

Good point on rifles factory threaded 1/2x28 to use an adapter for 5/8x24 direct thread.

We aren't as limited on getting a barrel threaded to 5/8x24 as one may think.

Kampfeld custom is a great example. Karl will thread with a collar for .630" and larger (he did one for me), and also thread less than .630 to 5/8x24 with what appears to be a bigger collar for a bit more money...he can explain it better than me.

And i wouldn't hesitate to have Karl do another for me.

 

[Hnthrdr]

Heaven forbid you order an adapter without certified material test reports, hardness certification, and 3rd party tolerance measurements, you’ll be told you’re a fool! (Exaggerating)

What if they come as a 2 pack with a nice little plush bag? Haha good to go right?

 

[swavescatter]

I don't think cost has anything to do with it. Cheapo amazon thread protectors, Downrange adapters and Silence Central Banish adapters have all worked great. The only issue I've had was with Gucci adapters from SRS - threading was off and I had to spin my barrel off and ship to my gunsmith. He confirmed the SRS adapters were not machined to spec and fixed them. In short - don't trust anyone, and if something feels off just back it off.

TI PRO CB / BANISH GOLD SUPPRESSOR MOUNT AND SPANNER BUNDLE – Salmon River Solutions

www.salmonriversolutions.com

 

[River Reaper]

I started a similar thread about adapters and got some great advice. I’ve since installed 3 adapters with no issues. Granted, all 3 are on .224’s going through .30 cans. I’ve also stacked a QD muzzle device on top of the adapter on 2 different rifles without issues. Just my limited experience, but I’d recommend for similar applications.