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Page AR-15 » Build It Yourself
AR Sponsor: bravocompany
Posted: 7/27/2009 9:05:40 AM EDT
I am fixing to order a bunch of tools and want to make sure i am not forgetting something.
Is it a special tool to install the A2 Buttstock Assy?
I was going to get the Armorors wrench from PK Firerams.

Do I need the stock wrench too?

Or the HD stock nut wrench?
BRD.....
Thanks!
Link Posted: 7/27/2009 9:10:48 AM EDT
[#1]
All you need is a flat blade screwdriver.
Thread the buffer tube in by hand and if you can, get it tight by hand, or use a cresent wrench on the flats on the rear.  
Then slide the stock over and run the screw in tight.

Link Posted: 7/27/2009 9:12:04 AM EDT
[#2]
The stock nut wrench is for the castle nut on collapsible car-bean stocks only iirc.  Shouldn't need it with A2 stocks.
Link Posted: 7/27/2009 5:38:28 PM EDT
[#3]
The lower wrench gives you three contact points to install or remove the locking nut on collapsible stocks, the upper wrench can do the same job, but only has the one pin that vaguely looks like a spanner wrench.  The upper wrench has a large flat on the tail end that should fit the buttstock screw, or you can simply use a crescent wrench to install the tube, then a screwdriver to install the stock as was said by a previous poster.
Link Posted: 7/27/2009 6:32:24 PM EDT
[#4]
OK guys thanks for the info...I'm learning...slowly
Link Posted: 7/27/2009 7:01:09 PM EDT
[#5]
The Armorer's wrench has a slot (opposite the compensator slot) that will fit the buffer tube.  I don't recall the exact torque and will not quote from memory for fear of being wrong, but on my last install the tube end would have deformed significantly if I had used a crescent wrench.  By using the Armorer's tool and a torque wrench, all went exactly as planned.

You DO NOT need the carbine wrench = bottom picture.  Your call on if you want to get the right tool for the job or not.
Link Posted: 7/27/2009 7:16:49 PM EDT
[#6]
Quoted:
All you need is a BIG flat blade screwdriver and a wrench to fit the end of the receiver extension.
Thread the buffer tube in by hand and if you can, get it tight by hand, or use a cresent wrench on the flats on the rear.  
Then slide the stock over and run the screw in tight.



Fixed.

ETA:  But get the armorer's wrench.  Lots of convenient tools there.
Link Posted: 7/27/2009 7:57:52 PM EDT
[#7]
Link Posted: 7/27/2009 9:07:54 PM EDT
[#8]
I'm a bit confused on the torquing to 35-39 ft-lb part.  Don't you just screw the receiver extension in until it's at the right spot to hold the buffer retainer down?  

My first build is nearly complete, only missing the stock assembly, it's going to have either a rifle or entry length receiver extension and this torque thing has been confusing me for a while now.
Link Posted: 7/27/2009 11:00:15 PM EDT
[#9]
There is a lip on all rifle buffer tubes.  Carbine tubes have a nut.

This lip is machined into the tube and not adjustable.

You push the buffer retainer and spring down and screw the tube in till it stops against the lip.  Tighten it just like a bolt or screw 35 foot lbs.  You want to get the tube tight and not let it be loose.  If the buffer retainer binds on the tube the only option to adjust is to grind a bit of  metal off the tube in the area that is binding.  Rifle tubes probably never need this done.  I have never seen it myself.

Carbine tubes are a different story.  You must screw it down enough to grab the retainer.  You want it almost up against the retainer post.  One turn out will still usually grab the retainer but not very well.  Then tighten the nut and plate.  There was a post on here talking about needing one filed down a bit because the post of the retainer was binding on the forward edge of the tube.
Link Posted: 7/28/2009 6:27:39 AM EDT
[#10]
Oh Oh...I have never lubricated the threads of my lower receiver extentions on my A2's and A1's with grease when installing them in my lowers. I have never heard or read of this before.
Do you think I should remove them, grease them, and re-install them? It has never been a problem that I know of or have ever heard of...Thanks for your opinons and input....<><....:)
Link Posted: 7/28/2009 10:30:53 AM EDT
[#11]
The main reason for the grease is corrosion resistance between the steel and aluminum.  When dissimilar metals are close together they can share electrons.  Depending on which metals some share them more easily than others.  If you have one metal that shares them lot more easily than the other or one that accepts them a lot more easily than the other corrosion growth can be accelerated.  

The other reason is for ease of removal.  If its aluminum on aluminum I would not worry about it unless you plan on removing it in the future without damage to the threads.  I would however grease my steel barrel nuts or carbine stock nuts.

http://www.engineersedge.com/galvanic_capatability.htm

The closer the metals on this chart are to each other the safer they are together.
On the other hand gold and magnesium together probably would not work very well.
Link Posted: 7/28/2009 2:38:31 PM EDT
[#12]

Quoted:





The main reason for the grease is corrosion resistance between the steel and aluminum.  When dissimilar metals are close together they can share electrons.  Depending on which metals some share them more easily than others.  If you have one metal that shares them lot more easily than the other or one that accepts them a lot more easily than the other corrosion growth can be accelerated.  
The other reason is for ease of removal. If its aluminum on aluminum I would not worry about it unless you plan on removing it in the future without damage to the threads.  I would however grease my steel barrel nuts or carbine stock nuts.
http://www.engineersedge.com/galvanic_capatability.htm
The closer the metals on this chart are to each other the safer they are together.




On the other hand gold and magnesium together probably would not work very well.





I agree with you about ease of assembly/disassembly as far as you state.  From my experience using aluminum AN fittings for fuel and hydraulic lines, when screwing aluminum threads to aluminum threads you ought lube the threads otherwise they will gall themselves during assembly.  At that point you're pretty well screwed (so to speak).  Tight fitting unlubed aluminum treads will chew into each other when they start torqueing down to the point where they're either ruined and leak, or ruined and cold weld themselves together making it impossible to finish assembly or almost impossible to take them back apart.  This is a separate issue from any galvanic reaction or corrosion and as I said happens during the assembly.  Anodized aluminum does it as easily as raw/clean/fresh aluminum.  I've had to throw away dozens of fittings that were ruined by not lubing them by people other than me (after my first two ruined fittings).
 
Link Posted: 7/28/2009 3:35:58 PM EDT
[#13]
Quoted:
Oh Oh...I have never lubricated the threads of my lower receiver extentions on my A2's and A1's with grease when installing them in my lowers. I have never heard or read of this before.
Do you think I should remove them, grease them, and re-install them? It has never been a problem that I know of or have ever heard of...Thanks for your opinons and input....<><....:)


I see no reason to take it apart and lube it.  If you ever have your stock and receiver extension off, do it then.  I think the purpose it serves is merely to prevent galling during assembly.
Link Posted: 7/28/2009 3:53:17 PM EDT
[#14]
Quoted:
Quoted:
Oh Oh...I have never lubricated the threads of my lower receiver extentions on my A2's and A1's with grease when installing them in my lowers. I have never heard or read of this before.
Do you think I should remove them, grease them, and re-install them? It has never been a problem that I know of or have ever heard of...Thanks for your opinons and input....<><....:)


I see no reason to take it apart and lube it.  If you ever have your stock and receiver extension off, do it then.  I think the purpose it serves is merely to prevent galling during assembly.


This, if the damage is done, it is exactly that....
Link Posted: 7/28/2009 6:22:49 PM EDT
[#15]
Quoted:
There is a lip on all rifle buffer tubes.  Carbine tubes have a nut.

This lip is machined into the tube and not adjustable.

You push the buffer retainer and spring down and screw the tube in till it stops against the lip.  Tighten it just like a bolt or screw 35 foot lbs.  You want to get the tube tight and not let it be loose.  If the buffer retainer binds on the tube the only option to adjust is to grind a bit of  metal off the tube in the area that is binding.  Rifle tubes probably never need this done.  I have never seen it myself.


Excellent, thanks for the explanation ekg98.  I've never looked at a rifle buffer tube off a lower before so I never noticed the lip.

So how important is it to get exactly 35-39 ft-lbs of torque?  I don't have a torque wrench.  From the posts above it seems like most just use a crescent wrench and don't actually measure the torque.  I have no concept of the amount of force required to torque to 35-39 ft-lbs with a wrench.  Would this be comparable to the amount of energy you exert to curl a 35lb dumbbell (trying to come up with an analogy, that's the best I could think of)?

Is it worse to over or under torque if I'm going by hand without a torque wrench?  Or do I really need to get the torque wrench?

Thanks
Link Posted: 7/29/2009 1:42:44 AM EDT
[#16]
Harbor freight sells torque wrenches for pretty cheap.  35ft lbs is enough torque that if the wrench is not perfectly on the tube you can round off the flats.  You want it tight enough so it wont come loose but not so tight that you can never get it off or start to damage the flats.  You can just tighten it with a normal wrench.  I have even installed one in my bedroom.  Just put a towel down on the bed and sit gently on your rifle and tighten.

Foot pounds or Inch pounds are measurement of torque.  Just image a weight that weighs 35 lbs on the end of a wrench that is 1 foot long.  I deal with quite a few torque wrenches in my field.  On a ar15 buffer tube its not too critical.  I torque all mine and try and follow the manual.  I have nothing else to do however.

I know from experience my calibrated elbow can with a screw driver install screws between 35 to 40 inch pounds.  That is 3 foot pounds.
Link Posted: 7/29/2009 7:17:33 PM EDT
[#17]
Thanks again ekg.  I guess I'll try installing it with just a wrench.  I might even try your sitting on the rifle trick since I don't have a vice.     I'm pretty poorly equipped for an AR build, that's why I went with a complete upper instead of attempting to build one.  I didn't think I'd need any special tools for the lower with a fixed stock.

I also don't have any moly grease...I should probably check out an auto parts shop and find some.  Hopefully they sell it in small quantities so I don't have to buy a whole tub of it for one receiver extension.
Link Posted: 7/30/2009 1:59:38 AM EDT
[#18]
Just apply the German torque method.  Goodandtight.  Just make sure your grease does not contain graphite.  Corrosion reasons from the post above.  I bet even someone on the board here could send you a small cap full of Aeroshell 33MS if you ask around.
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