Muzzle Brake Removal, Arsenal AK47


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kkayser
December 26, 2013, 11:59 AM
The brake has a right hand thread and is held in position with a spring loaded pin. I have tried Aerokroil, carbon remover, and Breakfree. While supporting and protecting the ears ofthe sight, I have applied a lot of torque. The brake refuses to move. I am hesitant to apply more than 100 ft-lbs of torque. If I apply 100 ft-lbs of torque, the end of the sight is getting about 1200 lbs of force. (The supported part of the sight is about 1 inch long.) This is like running over the sight with a car. I have two more methods in mind:

1. Submerge the brake thread in boiling water. I will use a large kettle so that the rifle does not cool the water. This has the advantage that the brake will be heated rapidly. The idea is to get the brake to expand while minimizing expansion of the male threads.

2. Use an impact wrench. I'll fashion a steel bar with a double nutted bolt. put the bar through the brake, put the wrench on the bolt and carefully pull the wrench trigger in short bursts. I'll also start with the wrench at minimum torque.

Unless someone tells me that the impact wrench technique has been done without damaging the rifle, I may just accept the fact that this brake cannot be removed without destroying it. I can cut the brake off with a band saw then use a Dremel tool to cut two slots down to the threads. I suppose, as a last resort, I could take it to a gunsmith, but, how am I going to find a gunsmith who has experience in removing brakes from AK's?

I would guess that threaded shotgun choke tubes have this same problem if they are left in too long. Maybe I should post on shotgun forums too.

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edfardos
December 26, 2013, 12:18 PM
Soldering iron?

rcmodel
December 26, 2013, 12:30 PM
Boiling water will not work to expand the threads.

The barrel will heat up slowly at the same rate the brake heats up slowly, and the thread tightness will remain the same.

In order to expand the threads rapidly, you will have to use a torch on the brake and heat it faster then the heat can transfer to the barrel.

Not to say though that boiling water might not get down inside the threads and loosen the carbon fouling, if that's what it is.

I would try soaking it in penetrating oil overnight, then try it.

rc

oneounceload
December 26, 2013, 02:01 PM
You might try a heat gun like they use for softening paint; you might try freezing the barrel; you might try to actually tighten it just a smidge to see if that breaks it loose - any of those three are trying to do the same basic thing, make one thread part slightly different in size from the other

rule303
December 26, 2013, 02:19 PM
Not to be a smart ---, but are you sure it is RH thread? Most AK's are LH. Also, what type of brake are you taking off? If it is a ban period brake, it may be soldered or welded. If it is a regular slant brake, I would just take a nut splitter to it, then replace it.

AK103K
December 26, 2013, 03:30 PM
What type of brake is it?

Are you sure its a right hand thread? If its a 14mm thread, its likely a left hand thread.

Whats the vintage of the gun? Many brakes were welded and/or blind pinned during the ban.

The only AK muzzle devices Ive come across that wouldnt come right off, were either welded or pinned, or both.

ClickClickD'oh
December 26, 2013, 03:37 PM
Since I have to ask... you did depress the pin right?

wally
December 26, 2013, 03:37 PM
The brake has a right hand thread and is held in position with a spring loaded pin.

A real AK with a 14mm muzzle thread is left handed. Are you sure Arsenal used a right hand thread? or is in an AK-74 style attachment which uses 24mmx1.5 right hand threads?

I've had good luck freeing stuck parts with an overnight or longer soak in penetrating oil and heat from a propane torch -- do it somewhere where smoke and a bit of fire won't hurt anything.

ugaarguy
December 26, 2013, 03:42 PM
I've merged the two threads into one. Please don't start duplicate threads.

briansmithwins
December 26, 2013, 05:27 PM
The standard for 14mm thread AKs is LH, the 24mm muzzle device standard is RH. Without knowing the model we can't tell which you're dealing with.

Before going crazy with the Dremel have you called Arsenal?

BSW

kkayser
December 27, 2013, 09:38 AM
The rifle is about 2yrs old and I cannot see any difference between it and my one year old AK74.

I know it is RH thread because I can see the threads in the slot which accepts the holding pin. Nevertheless, it will loosen either way because there is about 1/16th inch more to go (over a full turn screwing on) until the brake contacts the sight. I can turn either way to loosen.

I think boiling water will heat the brake faster than a torch. I intend to plug the bore with a rubber stopper so that the hot water cannot get to the barrel and heat it from the inside. I will try both a paint removing heat gun and a mapp gas torch. I have a surface thermometer and won't let anything get over 300 deg F.

I have placed a brass shim between the pin and the brake so that the pin cannot get into the slot.

kkayser
December 27, 2013, 10:04 AM
I have a splitter, but it requires so much force to split steel that I would be afraid of deforming the barrel or severely damaging the male threads. The Dremel tool with take a while, but should be safer.

I have had Kroil and Silikroil in the threads for a few weeks now, but have not tried soaking in penetrant. I have an old gallon can of 5-56, I'll try that next.

I wonder if an ultrasonic cleaner might loosen whatever is freezing the threads.

kkayser
December 27, 2013, 10:36 AM
Soldering iron?
Too slow. Irons do not transfer heat efficiently unless there is molten solder between the iron and the workpiece. With painted surfaces solder will never wet the surface.

kkayser
December 28, 2013, 08:50 AM
The standard for 14mm thread AKs is LH, the 24mm muzzle device standard is RH. Without knowing the model we can't tell which you're dealing with.

Before going crazy with the Dremel have you called Arsenal?

BSW
I called Arsenal originally. She said she would call back, but never did. I'll try again.

1KPerDay
December 28, 2013, 03:19 PM
I think boiling water will heat the brake faster than a torch.
Not on my planet... :confused:

ugaarguy
January 10, 2014, 09:49 PM
I've moved this to gunsmithing and repairs since the OP is still trying to solve the issue. Any help you folks here can provide would be great.

Kp321
January 11, 2014, 06:08 PM
It really sounds like the brake is welded, soldered or pinned in place. Look very closely and see if there has been a pin inserted and welded into the threaded area.

kkayser
January 13, 2014, 09:42 AM
It really sounds like the brake is welded, soldered or pinned in place. Look very closely and see if there has been a pin inserted and welded into the threaded area.

It is not welded because welding would show. It is not pinned. It could be soldered; it could also have thread locking adhesive. It is identical to my AK74 which is new. The brake on the 74 removes easily. I can see a few threads in the recess for the spring loaded pin. There is no sign of solder or adhesive. But that does not mean that they are not present on another part of the threads.

Solder and welding are unlikely because the barrel and brake were painted separately.

AK103K
January 13, 2014, 09:56 AM
Solder and welding are unlikely because the barrel and brake were painted separately.
If thats the case, I would say its even more likely.

Ive removed blind pinned brakes on a number of rifles, and you couldnt tell they were pinned and welded, until you took a file to them.

Blind pin and weld is, I believe, the preferred ATF method of permanent attachment. They drill a hole in the brake across the barrel from one side, and stop short of going all the way through. Then they weld over the side they drilled. If they do a good job, and its painted over, you'll never see it.

My old Arsenal SR-85C was the first brake I encountered that was in fact welded on. They did it cheaply (and incorrectly), and like you, I didnt think it was done at all. I thought it was rusted in the threads, and turned it off with a pair of vice grips. On closer examination, I saw it had in fact been welded, by drilling a hole in the bottom of the brake, and simply welding the hole up, which really didnt do much. I simply had to hit the threads with a thread file, and they were good to go.

kkayser
January 16, 2014, 09:24 AM
If thats the case, I would say its even more likely.

Ive removed blind pinned brakes on a number of rifles, and you couldnt tell they were pinned and welded, until you took a file to them.

.

If someone ground a weld on this brake, he should be restoring Ferrari's not welding AK's. The surface is perfectly smooth and round with uniform surface texture.

AK103K
January 16, 2014, 04:38 PM
I took brakes off two ban era Armalites, and I had a hell of a time finding the the welded pin in both.

I had to file the finish off, all the way around the brake, until I found the end of the pin, and then I had to try and figure out which way it was going and try and file down to it, until I had enough exposed to get a bite on it with a punch, and drive it out. They are a "blind" pinning, and there is only one hole. They didnt drill all the way through the brake.

Even my SSR-85C's weld, as badly as it was done, was very hard to see.

wally
January 16, 2014, 07:20 PM
I think boiling water will heat the brake faster than a torch. I intend to plug the bore with a rubber stopper so that the hot water cannot get to the barrel and heat it from the inside. I will try both a paint removing heat gun and a mapp gas torch. I have a surface thermometer and won't let anything get over 300 deg F.


300 deg F won't even release JB Weld. You need 500 deg F to release Red Loc-Tite, about 750 deg F for plumbers solder.

I'd use propane instead of MAPP gas as with Oxygen its just a notch below Acetylene (give up a bit of heat to get a much narrower explosive mixture range so generally safer for small scale intermittent usage).

kkayser
January 18, 2014, 02:09 AM
I put the rifle in the freezer overnight, then plunged it into boiling water. The water raised the temp to 180 deg in 15 seconds. Applied 80 ft-lbs torque - dead tight. The problem here is that 150 degrees difference between the male and female threads amounts to only 0.001 inches per inch. And the threads are only a little over an inch diameter. 0.001 inch is only 0.0005 all the way around. Apparently, this is not enough to break a bond of carbon. Oh well, it was worth a try.

kkayser
January 18, 2014, 02:20 AM
Has anyone ever seen a rifle which came from the mfgr. with BOTH a spring loaded pin AND another means of preventing a brake from unscrewing: solder? locktite? pin at right angle to the barrel axis?

I can think of no rationale for doing this except to deceive someone (like me) into thinking that the brake is easily removed.

JHansenAK47
January 18, 2014, 04:16 AM
Has anyone ever seen a rifle which came from the mfgr. with BOTH a spring loaded pin AND another means of preventing a brake from unscrewing: solder? locktite? pin at right angle to the barrel axis?
Pins and welds are the staple for most manufacturers to permanently attach muzzle devices for import requirements. I've seen the spring and plunger present on rifles with welded barrel nuts.
Have you been shooting corrosive ammo? Chinese or Yugo M67 perhaps?
I usually pull my brake off my SGL21 whenever it gets shot. I stick my cleaning rod through the opening in the end of the brake and torque it off that way. A wooden dowel or brass rod would be good alternatives. Hate to say it but you may need a lot of torque and possibly a cheater bar if it's rusted solid.

kkayser
January 18, 2014, 10:07 AM
Most of the ammo has been Wolf: Military Classic and Performance. I have also used PPU and Fiocchi. Wolf is the most accurate.

I have applied about 80 ft-lbs torque. I am hesitant to go higher because this amount puts at least 800 pounds on the sight and at least 4 times that much on the openings I put the bar through.

I think what I'm going to do while I let it soak in the Hoppes is get a steel bar about the size of the sight. I will drill a hole to simulate the threaded hole for the sight post. Then, put it in a vise and see how much torque it can take before it bends. If I use only half of that, I should be ok.

As for being pinned, I think I can get it x-rayed for a nominal charge. That should show a pin if there is one.

I have pounded on it with a plastic tipped hammer. But, it is a small hammer. I think I will buy a cheap 2# plastic tipped hammer and give hammering another try.

BBBBill
January 18, 2014, 10:25 AM
I took brakes off two ban era Armalites, and I had a hell of a time finding the welded pin in both.

I had to file the finish off, all the way around the brake, until I found the end of the pin...

Same here. There are apparently some manufacturers who did their best to conceal the pin/weld.

kkayser, unless you really have to have the brake undamaged/in one piece, you're wasting your time fighting it. Just grind it until you find the pin. Once you get past the weld, you should be able to get it out and get the brake off with no damage to the barrel.

AK103K
January 18, 2014, 01:01 PM
kkayser,

Have you contacted Arsenal and asked them if it is, or isnt pinned?

At the very least, they should be able to tell you whats up.

kkayser
January 19, 2014, 12:10 PM
I soaked it in Hoppe's 9 for a few days. The Hoppe's removed whatever was making the brake black. I am down to bare metal now. I can see the machining mark from the lathe which turned the brake. Therefore, if the brake is pinned, it was machined in a lathe after pinning. This could be done by mounting the sight assy. (with brake threaded on) on a steel rod the size of the barrel and chucking it in a lathe.

I'll try calling Arsenal again; the last time was a total waste of time. This time I will be insistent on talking to someone who knows about brake removal. Lots a luck on that.

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