View Full Version : How can I safely loosen tight threads?
I'm getting ready for my first-ever FF handguard install (see https://www.m4carbine.net/showthread.php?t=104155 ). I'm reading a lot of accounts of broken uppers and other nightmares in getting the barrel nut off, as well as trouble in general with other tight threads such as with removing flash hiders.
I've got a receiver block, barrel-nut wrench, and barrel block coming in my Brownells order along with everything else for the FF install, so am hoping for the best. I'm still expecting difficulty though, based on that getting the FSB pins out last weekend was a major battle.
Can I assume that WD-40 is a first step toward loosening the threads? That's what I've always used on any non-gun related work.
Secondly, is heat from a propane torch advisable, and safe for all rifle components? Again, I'm just going on work-related experience here.
Are there any other considerations, other than just go-slow?
Lastly, once I hopefully get everything off and am ready to re-assemble, should I put anything on the threads to make it easier next time, or should they just be as clean and dry as possible?
I'm looking forward to this project making a better rifle, and not a smoldering pile of wreckage. Thanks for any help.
Every time somebody brings up a seized nut/screw/whatever, the gun-wrenchers scramble over each other to post "Use Kroil! Let it sit!" I know that the former-2112 primate that geo-bachelors at my place will reach for that first, be it for a gun or a brake drum on a truck, and save WD-40 for polishing the top of his table saw. I have yet to see Kroil + time not work.
Robb and others speak to putting moly-disulfide grease or similar on the threads as an anti-seize.
On a whim, I punched in "anti-seize," limited it to AR Technical, and got these returns. Lots of references to barrel installs on the first page, alone. You may find some references to use of heat, too: https://www.m4carbine.net/search.php?searchid=4302038
When you reference "receiver block" is this the clamshell type that fits into a vise?
If not, that is what you need.
Barrel nuts can be tough.
Thanks for the replies and info.
When you reference "receiver block" is this the clamshell type that fits into a vise?
If not, that is what you need.
Barrel nuts can be tough.
I ordered this: http://www.brownells.com/.aspx/pid=17094/Product/AR-15-AR-STYLE-308-UPPER-RECEIVER-BLOCK
This is the most ideal. http://www.brownells.com/.aspx/pid=22385/Product/AR-15-M16-UPPER-RECEIVER-ACTION-BLOCK
It will give the receiver much more support while tightening the barrel nut. Muzzle device as well.
If having trouble getting the barrel nut off, use Kroil or Liquid Wrench and give them time to work.
Suwannee Tim
05-02-12, 10:18
Funny, everyone on the gun forums recommend Kroil. Every millwright, power plant mechanic, utility pipe fitter, etc. I know use PB Blaster (http://www.pbblaster.com/). I once saw a bunch of millwrights go on a wildcat strike because they were required to use something other than PB Blaster.
Make sure you get a wrench with many points of contact with the nut and make sure that the wrench is fully seated onto the teeth. Apply steadily increasing pressure to the wrench, do not bounce the wrench.
Make sure you get a wrench with many points of contact with the nut.....
This is what I ordered: http://www.brownells.com/.aspx/pid=27412/Product/AR-15-M16-AR-10-reg-BARREL-NUT-WRENCH
Neither the block nor wrench I'm getting appear to be the ideal. I wasn't expecting Brownells to be hocking second-rate tools.
....Apply steadily increasing pressure to the wrench, do not bounce the wrench.
I've read of people hitting the wrench with a hammer and thought: This can't be right. :fie:
1. I think you're probably worrying for no reason. Get the tools and try it before you worry about whether it's too tight or not.
2. I have used the clamshell upper blocks, but I prefer the DPMS Panther claw. The clamshell can scratch the upper and won't work with some of the new billet types (VLTOR). Yes I realize it's a weapon and scratches don't matter, but tell that to a customer who's paying you to work on his gun.
3. The PRI wrench is excellent. The USGI wrench only has three prongs, so there's more occasion for slippage. Compared to that, the PRI is great.
The key to this is proper support (vice & receiver block), proper tools (good barrel wrench and torque wrench/breaker bar), and steady pressure. As another poster said, don't jerk or bounce the wrench.
As far as lube for threads (when installing the new nut) I did a search and the consensus was Brownells ALP. It's moly-based with no graphite content. Scottyryan approves of it, so it must be good!;)
When using a claw-type block instead of the clamshell, I find it to be a good idea to put the upper on it's side with the top railed portion of the receiver against a padded jaw insert.
Here's how I do it:
http://i854.photobucket.com/albums/ab104/ASH556/IMG_8090.jpg
Brownells ALP:
http://i854.photobucket.com/albums/ab104/ASH556/IMG_8091.jpg
http://i854.photobucket.com/albums/ab104/ASH556/IMG_8092.jpg
.....Get the tools and try it before you worry about whether it's too tight or not.
......The clamshell can scratch the upper.......
......The PRI wrench is excellent.......
I was planning to proceed -- carefully -- using what I had already ordered before getting further :fie:'d.
Good point about the clamshell type block, and glad to hear that the wrench I'm getting isn't a dog.
.....a good idea to put the upper on it's side with the top railed portion of the receiver against a padded jaw insert......
Velly crever!!! I will definitely get a set of jaw pads and use that config -- thanks.
Funny, everyone on the gun forums recommend Kroil. Every millwright, power plant mechanic, utility pipe fitter, etc. I know use PB Blaster (http://www.pbblaster.com/). I once saw a bunch of millwrights go on a wildcat strike because they were required to use something other than PB Blaster.
I don't use Kroil. I use Liquid Wrench which I believe is about the same as the PB Blaster. Both work well.
When using a claw-type block instead of the clamshell, I find it to be a good idea to put the upper on it's side with the top railed portion of the receiver against a padded jaw insert.
Here's how I do it:
http://i854.photobucket.com/albums/ab104/ASH556/IMG_8090.jpg
I like the way you think. ;)
This is what I ordered:
I prefer more teeth to less, though I have at least one of each kind.
Smith Ent Wrench (http://www.brownells.com/.aspx/pid=24190/Product/AR-15-M16-AR-STYLE-308-ARMORERS-WRENCH)
I wasn't expecting Brownells to be hocking second-rate tools.
They rarely do, it's the craftsman not the tool. ;)
This can't be right. :fie:
No limit on stupid in this world.
Saw this in a Mauser forum it may help http://mausercentral.com/barrelremove.htm
Saw this in a Mauser forum it may help \.http://www.mausercentral.combarrelremove.htm
I think you meant http://mausercentral.com/barrelremove.htm
Markasaurus
05-02-12, 18:31
After 30 years of automotive work, I know a couple things about tight fasteners that pretty much work on everything.
Vibration is very helpful in getting a tight fastener off without destroying it. If that nut is fighting you, try this. Use a thin block of wod, to avoid marring, and a stel hammer. Place the wood over the nut and start banging on it. No need to wallop it, just tap, tap, tap it maybe about 40-50 times. This will also assist your lube to creep into the threads.
Next, use your wrench to TIGHTEN the nut a little. Now try to loosen it. Repeat several times. If this don't do the trick, I'd give the tap method one more try. Then i'd use a 3 foot long pipe for a breaker bar and most likely the nut will break loose.
I think you meant http://mausercentral.com/barrelremove.htm
Thank you for the correction hals1
I've only built a few ARs, but having spent a good part of my career as a sail boat rigger, I know a LOT about stuck aluminum.
1] PB Blast > Kroil > WD40
2] I'd bet that you are going to find it easier than you are fearing, but if it is not coming easy, Get the wrench on it, load it up, and strike the wrench with a hammer- it needn't be in the direction of the wrench, and it shouldn't be hard- just a few 'ringing' taps will usualy do it.
3] the tiniest amount of Never- Seize you possibly apply is a little more than you need, and will get EVERYWHERE.
4] a LITTLE heat is plenty, and Aluminum is tough to judge. About 400-500 degrees f is plenty. Heat, a little PB Blast, let it cool, heat it, PB, then try the wrench. A heat gun is better than an open flame, and DO HAVE A WET RAG HANDY. And a fire extinguisher.
Suwannee Tim
05-02-12, 20:20
Every flash hider I have removed so far, a good six or seven, have not fit my two open end wrenches very well. I have a 12 inch Crescent wrench which can be adjusted to fit perfectly. This wrench is nearly new and the jaws are not all beaten up and loose and out of parallel like a well used adjustable wrench usually is. I usually don't use an adjustable for heavy wrenching but in this case it works well.
One of our members, Mistwolf cited a Boeing directive forbidding the use of filled anti-seize compounds on aluminum as in AR15 barrel nut to upper application. I'll see if I can find that info.
Every flash hider I have removed so far, a good six or seven, have not fit my two open end wrenches very well. I have a 12 inch Crescent wrench which can be adjusted to fit perfectly. This wrench is nearly new and the jaws are not all beaten up and loose and out of parallel like a well used adjustable wrench usually is. I usually don't use an adjustable for heavy wrenching but in this case it works well.
One of our members, Mistwolf cited a Boeing directive forbidding the use of filled anti-seize compounds on aluminum as in AR15 barrel nut to upper application. I'll see if I can find that info.
Used properly, an adjustable wrench is often the best tool for the job- and sometimes, it's the only tool you've got...
'Never Seize' and other anti seize compounds come in different formulations- I do know that the copper based ones are a no-go for aluminum joints.
CompressionIgnition
05-02-12, 23:00
[..] I do know that the copper based ones are a no-go for aluminum joints.
If you combine aluminum and copper, the aluminum will act as a sacrificial anode for the copper. For the same reason, one should never use copper-based anti-fouling compound on aluminum boats.
Don't forget that you'll have to punch the FSB pins and remove the FSB and FH before you can use the PRI barrel wrench.
Do NOT use a receiver clamp to hold the upper so you can remove the flash hider. Secure the barrel or the FSB to counter the torque of removing the FH if it requires any real force to remove, or re-install.
I've used the clam-shell reciever clamps for well over a decade without issues and highly reccomend it.
A gib plus 1 for the bownells moly paste/grease for anti-sieze. I still use a small pot I originally bought back in 2001 and it has served well for many, many builds, and I have also used it for triggers as well.
Have fun!
...One of our members, Mistwolf cited a Boeing directive forbidding the use of filled anti-seize compounds on aluminum as in AR15 barrel nut to upper application. I'll see if I can find that info.
It forbids the use of copper based anti-seize on aluminum due to, as was pointed out earlier, the fact it promotes dis-similar metal corrosion. There are other types of anti-seize that work fine and are called out for.
For aluminum AN fittings, the manual often specifies assembly lube
All great advice -- thanks.:smile:
The Brownells order is scheduled to arrive Monday. I'm going to soak the barrel nut and FH in Liquid Wrench penetrating oil/penetrant over the weekend. I'll also see what kind of non-copper grease I can find for re-assembly.
Shall report back with outcome/results.
I like the DPMS Panther Claw as a receiver block. I doubt there's much difference between Kroil and PB Blaster. As to heat, I'd generally prefer a heat gun to a torch since I think that there's less tendency to get too hot. On re-install, I've always used Neverseeze without regret. Interesting about the copper. I've never heard of it being a problem, but maybe I need to rethink that.
.
Galvanic Corrosion occurs when two dissimilar metals are placed in proximity in a conductive environment. In Marine applications, that would be salt water (highly conductive), but even ambient air is usually conductive to become an issue if precautions aren't taken.
Basically, you create a battery, and current will flow from Anode ('less noble) to Cathode (more noble) carrying material on the 'return path' at a molecular level away from the Anode and depositing it on the cathode, creating corrosion that will virtually weld the materials together, as well as destroying the less noble metal
Precautions to avoid Galvanic Corrosion are generally either Isolation or Sacrificial Anodes.
For Isolation, using a good thread locker (such as locite) or even a simple RTV compound to ensure the metals do not have a path for current flow between them.
Use of a sacrificial anode is generally not practical in a weapon application.
SO!
Either a good bond using a conductive compound or isolation using a non conductive compound are good ideas-
However, unless one frequently finds oneself crawling out of the surf with one's weapon, these will be minor concerns over the service life of the rifle.
I am not a metallurgy or Galvanic Expert, but as I mentioned earlier, about 12 years of dealing with SS and aluminum in the marine environment has left me with a more-than-passing familiarity with the subject.
link to the galvanic table
http://www.corrosionist.com/Corros1.gif
More importantly- DO NOT use a propane torch or other open flame to heat the barrel nut. Doing so can damage the aluminum by causing imbrittlement and loss of heat treat.
Be very careful with using a heat gun. Too much heat for too long will cause the loss of heat treat. In fact, unless you know the proper way to control the heat, know how long and how many times the alloy can be heated without loss of heat treat, I would strongly recommend against it
However, unless one frequently finds oneself crawling out of the surf with one's weapon, these will be minor concerns over the service life of the rifle.
This is likely the key point in the theoretical problem one might see using copper-containing anti-seize compounds.
More importantly- DO NOT use a propane torch or other open flame to heat the barrel nut. Doing so can damage the aluminum by causing imbrittlement and loss of heat treat......
Thanks for the heads-up. I won't use any heat at the receiver end.
I already used the torch to get the FSB pins out, and unsuccessfully trying to get the FH off. Warmed everything up pretty hot too. Hopefully these all-steel components weren't affected, but anybody please chime in if you think they might have been.
Did you punch out the FSB pins first and then try to remove the flash hider?
If so, put the FSB back together entirely, then clamp the FSB in the bench vise (with some heavy leather to protect the FSB) and then torque the flash hider off.
That is if you don't have barrel blocks, which are a far better option.
Littlelebowski
05-07-12, 20:19
Every time somebody brings up a seized nut/screw/whatever, the gun-wrenchers scramble over each other to post "Use Kroil! Let it sit!" I know that the former-2112 primate that geo-bachelors at my place will reach for that first, be it for a gun or a brake drum on a truck, and save WD-40 for polishing the top of his table saw. I have yet to see Kroil + time not work.
Robb and others speak to putting moly-disulfide grease or similar on the threads as an anti-seize.
On a whim, I punched in "anti-seize," limited it to AR Technical, and got these returns. Lots of references to barrel installs on the first page, alone. You may find some references to use of heat, too: https://www.m4carbine.net/search.php?searchid=4302038
Oil of wintergreen works better than Kroil for me.
Well I soaked both the FH and barrel nut in Liquid Wrench all weekend. Then everything from Brownells arrived Monday.
Good thing the barrel block worked as well as it did, 'cuz it did take a pretty good-but-steady umph to get the FH off.
Then I blocked up the receiver -- ready for more of the same -- but it just eased off like melted butter! :laugh: Boy was I surprised. Looks like that days-long soak had an effect.
Now the only problem is that the Troy Alpha FF I planned to install feels like a cheese grater on my hands -- should've ordered the VTAC version, but Brownells doesn't stock that. :sad: Oh well, must look further, but at least the potentially gun-busting part is over.
Thanks for everyone's input here.
Glad it all worked out for you. :D
Suwannee Tim
05-08-12, 20:25
It forbids the use of copper based anti-seize on aluminum due to, as was pointed out earlier, the fact it promotes dis-similar metal corrosion. There are other types of anti-seize that work fine and are called out for.
For aluminum AN fittings, the manual often specifies assembly lube
The three filled anti-sieze compounds I am familiar with are copper, lead (no longer available at least in the auto parts store) and moly. Probably graphite too, come to think about it. The purpose of moly in grease is an extremely high film strength for times when the grease film fails due to excessive pressure. Very valuable in a CV joint, less so in a static joint like an AR barrel nut assembly methinks. I think the moly particles are very small, a few microns but I don't know for sure. I think they are small enough to be harmless. You mentioned assembly lube, is this just a heavy oil or light grease, non-filled? In my limited experience which consists mainly of 5.45 mm barrels, I use transmission fluid. I shoot them till they smoke then shoot them some more. After several thousand rounds the nut and threads are still wet and easy to remove.
I use Loc-tite C5A anti-seize (with copper) and have used it for years with no adverse affects.
WD 40 works for me every time
Assembly lube is just a tacky lubricant, kinda like a heavy clear petroleum jelly. On aircraft, I must use what is specified in the manual. For non-aircraft use, my experience is that any lube that eliminates the typical aluminum-on-aluminum galling will work. Some work better than others when it comes to taking it all back apart.
In general, nickle anti-seize seems to work best for high heat applications, such as spark plug threads and exhaust system nuts & bolts. For ignitor plug threads on turbine engines, Milk of of Magnesia is often used. Our rifles will not experience the same temperatures and duration of heat as engines do
I use Loc-tite C5A anti-seize (with copper) and have used it for years with no adverse affects.
+1
Copper based (or nickel, if you can find it) anti-sieze is what I've been using. Also what we use at work on industrial presses, and it stays in working condition on those filthy machines for ages. (Note: Work in a brick plant, nothing but grit, heat, and dust in that place, and we rarely have stuck threads)
Regarding the upper holding equipment:
I deal with a place here in PA that has upper blocks made for them. They took the original pinned design and have a second half fabricated that slides over the rail to create a solid clamping surface. These things work wonders, but require a decent sized vice to operate. Simply not going to work on a three inch hobby vise. I'm not one for plugging products, but I've torn the pins out of a few blocks before getting this one. This one's going strong, and I've hung off the wrench trying to break barrel nuts free.
They're priced fair, and I know the guy ships. Last time I was in the shop, he had a few sitting there. Lanco Tactical in Elizabethtown PA. His site is a pain to navigate, but the blocks are on there.
Another plus for the guy, he answers emails. You can try him if you have a problem finding a suitable upper block.
Regards-
Roland
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