Concentric threads??

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Trvrswsr1234
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Joined: Sat Jul 11, 2020 10:04 pm

Concentric threads??

Post by Trvrswsr1234 »

Just made my first visit to my new Deadair nomad and wouldn’t ya know it the threads on my SGL aren’t strait enough to use it


More just curious then anything but have any of you guys had luck with concentric imports? Is there any known correlation of country of origin and strait threads like for example X country generally have strait threads or X country almost never does?


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nalioth
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Re: Concentric threads??

Post by nalioth »

Trvrswsr1234 wrote:
Sun Jul 26, 2020 2:23 am
Just made my first visit to my new Deadair nomad and wouldn’t ya know it the threads on my SGL aren’t strait enough to use it


More just curious then anything but have any of you guys had luck with concentric imports? Is there any known correlation of country of origin and strait threads like for example X country generally have strait threads or X country almost never does?


https://i.ibb.co/kBGg56D/7-C5-CF937-9-F ... 9-B726.jpg
Was the gun made on Hangover Monday?

Friday at Beer-Thirty?

Any day that ends in "y"?

There is no rhyme or reason to how the barrels come out of the forge - the commies shitcan the ones that are grossly out of spec.

Woodpusherpro!
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Re: Concentric threads??

Post by Woodpusherpro! »

Alot of times the actual bore for the rifling is not the same distance from the outside diameter. It's not only the threads that aren't concentric.

1biggun
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Re: Concentric threads??

Post by 1biggun »

Woodpusherpro! wrote:
Sun Jul 26, 2020 3:00 am
Alot of times the actual bore for the rifling is not the same distance from the outside diameter. It's not only the threads that aren't concentric.
The bore not being in the center of the barrel is the definition of the threads not being concentric to the bore .

Deerhurst
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Re: Concentric threads??

Post by Deerhurst »

Not necessarily. Threads could be crooked too which would satisfy the non concentric label.
|5.56x45|5.45x39|7.62x39|9x19|7.62x25| and others I've forgotten..

esh21167
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Re: Concentric threads??

Post by esh21167 »

^Right. The bore, the OD, and the threads could all have different centers or axes skewed.

TX-Zen
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Joined: Mon Jul 20, 2020 2:52 am

Re: Concentric threads??

Post by TX-Zen »

Deerhurst wrote:
Sun Jul 26, 2020 10:39 pm
Not necessarily. Threads could be crooked too which would satisfy the non concentric label.
+1
From what I've seen on the 24x1.5 FSB this is typically the problem. The problem usually isn't having a barrel drilled off center

Micropeenus
Posts: 10
Joined: Sat Jul 25, 2020 6:49 pm

Re: Concentric threads??

Post by Micropeenus »

If its a QD mount suppressor:

Send it to an AK gunsmith like Two Rivers.

Pull barrel.
Chop the barrel a couple inches and rethread.
Tac weld suppressor mount.
Enjoy.

Trvrswsr1234
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Joined: Sat Jul 11, 2020 10:04 pm

Re: Concentric threads??

Post by Trvrswsr1234 »

That’s a good point

I think if I’m gunna go with a solution that requires spending some cash I’d be better off just taking that cash and buying a Deadair wolverine

I wonder if the the bore itself was crooked if they’d be able to make that happen or not

TX-Zen
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Re: Concentric threads??

Post by TX-Zen »

The Wolverine isn't that great of a suppressor TBH, it will be very difficult to get it hearing safe, if it's even possible. It's only advantage is that it can help with concentricity issues but even then it's not a guarantee. I've had end cap strikes on mine several times, which is fixable because the end cap is replaceable, but it still happened even with a Wolverine

How exactly is it mounted...24x1.5 adaptor like the Griffin, or is it a factory mount? What rods did you use to test alignment?

Ironroots
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Re: Concentric threads??

Post by Ironroots »

Get the Jmac X37 muzzle device. I've used then on several guns and it's cured any concentricity issues. The reason for such issues isn't always bore or thread related, but the fact that the can shoulders on the front sight post (often causing the can to cant).

The x37 addresses this as the device is face mount designed (similar to the wolverine), so it butts up against the end of the barrel, leaving a small gap between the device and your front sight post. Shims are required to time the device properly.

This has allowed me to mount a 30 cal can on over 8 rifles that otherwise would've been unable to.

The only downside is that it is limited to specific cans, but the Nomad is amongst them.

1biggun
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Re: Concentric threads??

Post by 1biggun »

esh21167 wrote:
Sun Jul 26, 2020 11:05 pm
^Right. The bore, the OD, and the threads could all have different centers or axes skewed.
Well I guess the first thing to fucking do is for the OP to define what he means by crooked threads . You cant do much until you know what he actual problem is .

Since the threads on the AKs I have handled are lathe cut if there factory threads then generally the threads are straight to the OD of the barrel and concentric to that OD . The position of the bore is a another matter especially on a Rommy barrel .

Its the bore not being in the center ( Non Concentric to the OD ) of the barrel and often also Often not being a straight bore that is most often the problem .


Your going to play hell getting a crooked / wandering bore to work with a surpressor unless you true it off an mandrel or rod in the bore set up in a lathe . '

if the bore is not centered ( non concentric to the OD ) then you can true the OD and maybe install a adapter or something .

Trvrswsr1234
Posts: 25
Joined: Sat Jul 11, 2020 10:04 pm

Re: Concentric threads??

Post by Trvrswsr1234 »

Ironroots wrote:
Mon Jul 27, 2020 9:40 pm
Get the Jmac X37 muzzle device. I've used then on several guns and it's cured any concentricity issues. The reason for such issues isn't always bore or thread related, but the fact that the can shoulders on the front sight post (often causing the can to cant).

The x37 addresses this as the device is face mount designed (similar to the wolverine), so it butts up against the end of the barrel, leaving a small gap between the device and your front sight post. Shims are required to time the device properly.

This has allowed me to mount a 30 cal can on over 8 rifles that otherwise would've been unable to.

The only downside is that it is limited to specific cans, but the Nomad is amongst them.
That’s what’s on there now, I used a .30 bore rod and it’s very close to one side of the outlet hole on the end cap, I have anothe jmac 37mm device for my O-pap so maybe I’ll have better luck with that

Trvrswsr1234
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Joined: Sat Jul 11, 2020 10:04 pm

Re: Concentric threads??

Post by Trvrswsr1234 »

TX-Zen wrote:
Mon Jul 27, 2020 6:52 pm
The Wolverine isn't that great of a suppressor TBH, it will be very difficult to get it hearing safe, if it's even possible. It's only advantage is that it can help with concentricity issues but even then it's not a guarantee. I've had end cap strikes on mine several times, which is fixable because the end cap is replaceable, but it still happened even with a Wolverine

How exactly is it mounted...24x1.5 adaptor like the Griffin, or is it a factory mount? What rods did you use to test alignment?
It has a jmac muzzle brake the has 37mm thread on the outside that thread into the can and I used a Surefire brand rob, it wasn’t touching the end cap but it was damn close to one side

Trvrswsr1234
Posts: 25
Joined: Sat Jul 11, 2020 10:04 pm

Re: Concentric threads??

Post by Trvrswsr1234 »

1biggun wrote:
Mon Jul 27, 2020 11:43 pm
esh21167 wrote:
Sun Jul 26, 2020 11:05 pm
^Right. The bore, the OD, and the threads could all have different centers or axes skewed.
Well I guess the first thing to fucking do is for the OP to define what he means by crooked threads . You cant do much until you know what he actual problem is .

Since the threads on the AKs I have handled are lathe cut if there factory threads then generally the threads are straight to the OD of the barrel and concentric to that OD . The position of the bore is a another matter especially on a Rommy barrel .

Its the bore not being in the center ( Non Concentric to the OD ) of the barrel and often also Often not being a straight bore that is most often the problem .


Your going to play hell getting a crooked / wandering bore to work with a surpressor unless you true it off an mandrel or rod in the bore set up in a lathe . '

if the bore is not centered ( non concentric to the OD ) then you can true the OD and maybe install a adapter or something .
No idea which one it is frankly I would think the issue is the bore because how hard can it be to make the threads on the FSB strait but who knows we are talking about Russians after all


As far as fixing the problem I have no intention of modifying the SGL and will just look to a different rifle or perhaps a different can for my suppressing 7.62x39 needs

TX-Zen
Posts: 8
Joined: Mon Jul 20, 2020 2:52 am

Re: Concentric threads??

Post by TX-Zen »

If it's not touching the edge of the suppressor you should be fine. They don't have to be perfectly symmetrical to fire safely. I have a couple that are close the edge but not touching and they've been fine, but we each have to make peace with what we see during the rod test in our own way

Deerhurst
Posts: 67
Joined: Thu Jul 09, 2020 8:09 pm

Re: Concentric threads??

Post by Deerhurst »

TX-Zen wrote:
Mon Jul 27, 2020 6:52 pm
The Wolverine isn't that great of a suppressor TBH, it will be very difficult to get it hearing safe, if it's even possible. It's only advantage is that it can help with concentricity issues but even then it's not a guarantee. I've had end cap strikes on mine several times, which is fixable because the end cap is replaceable, but it still happened even with a Wolverine

How exactly is it mounted...24x1.5 adaptor like the Griffin, or is it a factory mount? What rods did you use to test alignment?
I run a hybrid on many of my rifles. My saigas isn't perfectly concentric but the huge bore of the hybrid makes it not a big deal. I'm still making hits on 2/3 IPSC steel at 300 yards with it so apparently accuracy isn't an issue either.

I haven't been very impressed with the wolverine. I'd go Wolfman or Chimera long before I run a wolverine.
|5.56x45|5.45x39|7.62x39|9x19|7.62x25| and others I've forgotten..

Woodpusherpro!
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Re: Concentric threads??

Post by Woodpusherpro! »

1biggun wrote:
Mon Jul 27, 2020 11:43 pm
The position of the bore is a another matter especially on a Rommy barrel .
I would say that may only be true because of how common Romanians are. All the hammer forged barrels are highyly suspect.

1biggun
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Re: Concentric threads??

Post by 1biggun »

Woodpusherpro! wrote:
Tue Jul 28, 2020 8:49 pm
1biggun wrote:
Mon Jul 27, 2020 11:43 pm
The position of the bore is a another matter especially on a Rommy barrel .
I would say that may only be true because of how common Romanians are. All the hammer forged barrels are highyly suspect.
I have most of them in a lathe at one tome or another .
the Romys or maybe the Egyptians are the worst
the few new polish ones I have messed with were decent as were the Hungarians .
Im not saying I stuck a rod in them or installed a suppresser but when spinning the romys on centers they IMO were the worst as fat as the OD being concentric to the bore and also the bore being straight .

I think Robert had some comments on different barrels about the bores to OD as well in a thread .

But yea any forged barrel is going to be suspect

On a lot of fire arms the OD and the ID as well as the chamber are hammer forged at the same time .
You want to see some real crap spin a newer Remington 700 take of barrel on centers . The bore is not only not true to the OD the OD is out of round . I had a lot of new 243 barrels all sporter profile ( 12 in total ) some of them were so out of round they shook the lathe when spun fast . then they were out of round in different places . Hammer forged junk .

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