If your not planning on knocking out 6 builds a week, then go look at some harbor freight coupons. I just snagged a 1/2 torque wrench from them for $10 with the coupon.

I think normally, their $21 +/-. I wasn't even going to bother with one, but at $10.. damn.

If for some reason, you can't get a hold of the coupons, then send me a pm. I might have one or two laying around I can mail you (coupons).

This ^.    HF is fine. While not the best available, it's plenty accurate when your torque specs call for a range of 30-80 ft. lbs.

wow, when i did my build i just borrowed a wrench because i figured i really wasn't going to use again, but for that price i might buy 2!!!

I'm still using mine that I bought years ago, when they came in a plastic case.  

Ive been looking at these. Has anyone had the accuracy or theirs verified? The price is good enough for me even if its only semi accurate, All my HF stuff is junk but the super coupons make it hard to say no

I was looking at one a few years ago, but then realized for $10 more than an HF one, I could buy a Craftsman beam style torque wrench.

There was a guy (on here I believe) that did a test with several name brand torque wrenches and the Harbor Freight was the most accurate! I can't give a link as it's been a while back.

http://www.carcraft.com/techarticles/ccrp_1304_torque_wrench_testing/

actually car mag did the test. linked above.

I had bought a harbor freight years back and had to turn it into a breaker bar in a pinch so I later replaced it with another as I no longer trusted it for accuracy.

Fast forward I had to rotate the tires on the wifes car and it had stock wheel covers that made it look like chrome rims (Chrysler Aspen) and it also had plastic covered lugs.  Well put those two together with a tire tech and a air impact and you have seized lugs.  After breaking most of them loose by having to stand on the wrench ( I am 270 pounds) the wrench finally popped.  I took it apart and flipped the guts around so it would only loosen but not tightened and was able to finish the job.

They are pretty stout for $20

I've used mine to assemble 3 and none of them have had any issue with loose barrel nuts or anything. It works well for me

You can pick up a craftsman beam deflection torque wrench for $22.99, 1/2" drive 0-150lbs.  Beam deflection is not always the best for multiusage but it is for barrel nuts.  Tells you exactly where you are at while torquing, instead of clicking and guessing.  WALDT though.
 

Broke mine working on a Duramax over a year ago…got another one to replace it and haven't opened it yet. They work well for barrel nuts though.

While it's sometimes useful to know how much torque you are applying, barrel nuts are not in that category.  As long as you put enough torque, but not too much, it really, REALLY doesn't matter if it's 54 or 39 or 72 foot pounds.  Really.  At the same time, a beam torque wrench requires you to watch the wrench, not your hands, so it cal lead to slipping and screwing up a barrel nut.  I learned that on my very first build.

Finally, all torque wrenches need to be verified, whether beam or click.  The process is the same whatever type you use.  Here are several links to "how to" procedures:
YouTube 1
YouTube 2
GL1800 Riders Forum How To
WikiHow Procedure - very well illustrated

i check mine on the snap-on truck every little bit and it has been accurate so far after about a year.

Totally understand your point.  From my standpoint I have torqued to 35 and aligned to the next notch before only to come up with close to 100 lbs.  I try to keep my all my barrel nuts at 50-55.  I am able to do this quickly and accurately with my beam deflection.  I have never had an issue yet with slipping and watching and the beam.  We all like different things though, no issues here with other ways.  I have a real good system down for myself.  And prefer to know where I am at torque wise instead of clicking and guessing.  It seems like a pretty simple operation to me.  I put one hand on the barrel nut, one hand on torque lever end of the wrench and watch back and forth.  I keep tabs when I get close to where I want to be.  It is amazing how much more torque it takes to get to the next alignment notch sometimes.  

 

Just my 0.02 but I dont believe in buying "cheep" tools what a decent middle of the road can be had for not much more.  Far too often I have bought somehting only to have to re-buy a better one cause it didnt hold up or meet my needs.  If you tend to do a lot of things with tools - Buy once cry once!

Right now Craftsman Torque "click" Wrench is $40 and a beam style is $20 on sale.  Check sear website.  

That said what ever wrench you buy you should check its accuracy and calibrate it once every few years or before a major project since its so easy to do and will be accurate enough for any hobby building activities.  Just lock up a bolt with several nuts on it in your vise with the nut closest to the bolt head protruding a little out the end of your vise.  Attach the socket to the bolt head and hang a few known weights and adjust the wrench till they all pass.  I use 10lb, 25lb,35lb, and 45lb fitness weight that I verified on load cell scales to be accurate within <1/2lb.  Since my wrench is 18" center of grip to socket this give me "data points" of
10lb = 15ftlb Torque
25lb = 37ftlb Torque
35lb= 52ftlb Torque
45lb = 67ftlb torque

For anything I am going to make this is close enough especially for building an AR that has such a wide range.  I would be more worried about "HOW" someone puts on their barrel nut than if its off by a few lbs.  In order to get a correct reading on a barrel nut I would only use Aeroshell 33ms grease (it meets mil-0spec MIL-G2-21164D, and since they came up with 30-80lb spec using such a grease its an apples to apples measurement) and make sure to step up the torque at 10lb intervals to stretch threads

Apply grease to threads on both barrel nut and upper - if new upper, Torque to 10ftlb leave 10min+, loosen 1/2 turn and re torque to 20ftlb and leave 10min+ and loosen 1/2 turn re-torque at final 30ftlb+ leave for 10min+ - take nut off, wipe off threads in case any burrs came loose and re apply grease and torque final time to first/lowest  alignment at 30-80lb.  If using a non indexed nut I torque mine to 40ftlb.  

If you want professional calibration you are looking at $35-$50 typically depending on your wrench which I would only go that precise if you are using it in the line of your profession or working on something VERY expensive and VERY precise torque range.  An AR Barrel nut is not such a beast.

I cannot for the life of me torque the castle nut correctly.  I take my torque wrench, attach to my armorers wrench, all in a row/parallel.  I try to then get the wrench on the nit and it is so awkward, I never am able to get it on there right to torque it.  I am not using a vise but regardless, how do you do it?  I am so lost.

I will be back at computer with in an hour. Will try to help you out when I get there... sent from phone.

Thank you so much.

Ok, first things first.  

You NEED a Bench Vise!  Do you need a $1000-1500 Wilton USA Bullet or Columbian?  Not unless you are a tradesperson who is beating the snot out of it every day.  You can find some old refurb quality vises on craigslist for a few hundred if you want to go that route.  As bleek as it sounds I know I am getting a VERY high end circa 1950's machinist vise that is in great condition from my Father when he passes away (He is in his 80's and was a tool and die man for over 50 years.  He has a very nice 6" Ductile Iron vise that weights almost 150lbs.  With proper maintenance this thing will hold up till my grand kids are using it and I dont even have children yet (36yr old).  I would take it now because he doesn't use it ever since his health issues (he has had in the last 6 years - lymphoma, cancer, heart attack, stroke, 2 brain surgeries, pneumonia 5 times) so we dont let him do much with tools any more, but you NEVER take a mans tools.  Its like taking away his man card and I just won't do it.  

Should you buy a $50 Harbor Freight vise?  NO those things are crap and will break or even split in half with anything other than LIGHT use.  Leave those for the childrens work bench.  

That said here are bench vises that will hold up under medium use that are reasonably priced.  Assuming you are the average homeowner they should give you many years of reliable service if not last the rest of your life.  The THIRD one does have a lifetime warranty but is the most expensive at $350.

$200 Yost 750-DI Combination Vise (Di stands for Ductile Iron) Home depot does not specify the DI in model number but description says 35,000psi ductile iron 5yr warranty Yost 750-DI

$200 Yost FSV-5 Machinist Vise (54,000psi yield - 90,000psi tensile strength Forged Steel) 5yr Warranty Yost FSV-5

$350 Wilton 6" Mechanics Vise (30,000psi Ductile Iron) Lifetime Warranty Wilton 6" Mechanics Vise

Now that the bench vise is out of the way.  Make sure you have it firmly attached to a stable work bench.  I am about to build a new bench for myself in the next month or so and would be happy to post pictures when I do.  The dimensions I am doing are 3ft x 6ft It will cost me about $150 in materials and have a load bearing strength in excess of 80lb per square foot and a total load capability of over $1,500lb (that is the load deflection based on L/360) to put in context the building code load deflection for most livingrooms is L/360@40psf.  Overbuilt probably, but I know it won't fail.  The legs would go through the floor before the bench brakes.  If you want to know how to calculate load deflection and span there is a lot of information on Google all be it a little overwhelming unless you're an engineer or came from a family of them.

Now how to use a torque wrench on your barrel nut

Clamping your upper into your vise horizontally from left to right (I am right handed) where muzzle would be left and butt stock would be right you will need one of 3 tools.  These are a matter of preference and each have their own advantage/disadvantage.  Since I dont want to start a flame war I will not recommend 1.  Take your pick on what you think will be best.  I have included links below.

$100 Geissele Reaction Rod AR-15 Geissele Reaction Rod

$46 DPMS Upper Receiver Action Block DPMS Action Block

$45 Model 1 Clam Shell Style Model 1 Clam Shell Style

Once upper is clamped into the vise lubricate the threads on your upper and your barrel nut and secure place the barrel into your upper making sure to fully seat the "Barrel Extension Pin" into the index notch in the upper.  Lubricate the threads with Aeroshell 33ms grease - Here is a good source for small quantity (enough for 2-3 rifles) 1/2oz jar of Aeroshell 33ms grease

Hand tighten the lubricated nut onto the threads.  Connect your barrel nut wrench to your torque wrench and insert it on your barrel nut at roughly the 1:00 to 2:00 position when looking at the barrel nut from the muzzle side of the gun.  This will allow you a natural arch motion when pulling down on the torque wrench.  

With your body parallel/squared off to the upper assembly and your right shoulder aligned with the barrel nut you will gently supporting the torque wrench and barrel nut wrench in your left hand pull downward toward your body with your right hand keeping your forearm at a 90deg angle to the handle of the torque wrench.  The pulling force applied should be in a line the direction traveling from your hand through your wrist down to your elbow.  PULL SMOOTH NOT JERK!  Since your right forearm (pulling hand) is at a right angle to the torque wrench and your body is parallel to the upper receiver this will give you the most accurate reading with out pulling the wrench in an odd angle (left right in out).  Step up the torque applied as I described earlier and you should be good to go.  If something is hard to understand please let me know, I know text instructions is hard to get sometimes.

Edits due to getting left right hands mixed up.  Had to read it and think it through.  Directions originally posted would have loosened the barrel nut.  LOL, I will call myself out its ok.

And to think all these years I've just been doing...good and tight.

I am not called CaptainOverkill for no reason.  Can we say OCD?  I am the OCD son of an OCD Tool and Die Man who was the son of an OCD Hungarian General. Too many generations being quoted as "Plan it threw and do it right or don't do it at all" or more to quote my Father.... "Do it right or don't even bother asking me to help".  For God sake I calculated the load bearing capability of the workbench I am going to build.

Somehow the HF torque wrenches are able to maintain their accuracy better than ones that can cost ten times as much.

At work we sent two HF 1/2" wrenches along with the rest of our stuff to get CAL'd on a lark.  

I was sure they would be waaay off.

Surprisingly, one was acceptable and the other was damn near perfect.

These are wrenches we use fairly often,  the really good one gets used a lot.

On the other hand we had a Craftsman wrench that sat in the box, hadn't even been used since last being calibrated by Craftsman,

that failed when checked.

Their digital calipers are a great deal also.  Bought three (@ $8 ea.), five years ago, thinking for sure they wouldn't last long.

I'm still using the first one, just had to change the battery once or twice.  Every once in a while I

check it against one of my bosses high $ caliper which gets CAL'd routinely and it does fine.

That's what I put "If your not planning on knocking out 6 builds a week"... blah blah blah.

Thanks for the input.

I  seriously doubt where a  harbor freight  is more accurate than all name brand torque wrenches

me and another mechanic did a test  on the tool truck with all of my torque wrenches (3) vs  his harbor freight that he just bought cuz he read where they were most accurate

mine were spot on and his was 8-12lb/ ft off  up to 75 lb/ft  and over 20  after 150,  but I am a  diesel mechanic  so I  have snap on and Matco

if you are just  using one to torque the castle nut and barrel nut the harbor freight one will work fine,  but for a professional mechanic its not advised

edited  for easier reading I apologize

Attempting to read that hurt my brain.

I had need of an inch-pound 3/8" drive one and picked it up for $20 at the local O'Reilly and it works fine. Home Depot apparently gold-plates theirs because they wanted $70 for one! I would have bought the Harbor Freight one if they were closer--I'm about 45 minutes from the store and needed it ASAP.

Here's the thing: if it takes more than 80 ft/lb, then back off and try again.  I had one take 6 tries before 30 ft/lb was anywhere near a notch, and a couple more tries before I got a notch lined up at less than 70 (I don't go up higher than that if I can help it - and I try hard to help it!).  The Army TM says to tighten to 30, back off and tighten to 30 again, repeat again, and THEN go for an aligned notch.  This distributes the grease thoroughly in the barrel nut threads, which helps even stresses throughout the assembly.  If you're going to "30 and then align a notch," you're going to run into a lot of difficulty.  The "back off and repeat" process takes a little bit of getting used to, but it works in almost all cases.  When it just doesn't work, that's the time to start thinking about trying a different barrel nut, or lapping the front of the receiver, or something else - it should NEVER be that hard to torque the nut properly.

Agreed GH.  I had not disclosed the whole methodology in how I tightened that particular barrel nut or others. Suffice it to say short of the one particular build, all my rigs get tightened to 50-55 without changing barrel nuts or lapping the receiver.  And I know exactly where I'm at with my beam deflection.  That rig did need a new barrel nut. Now I use a progressive tightening schedule that works beautifully and gets me at my desired anal retentive torque every time.  That post was merely to say that on that build the methodology you describe with the addition of last time running it over to the next notch. Which was not far at all.  I am not arguing with you at all.   We can disagree about what wrench gets us there I'm ok with that.  Just know our methodologies are not that far apart.  And my beam deflection has built me and assisted my friends in some very solid builds.  It's all good.  I definitely get that you know your stuff.  Have followed your posts for a while. Our differences of opinion are fairly minor. But I do favor the beam deflection so I know exactly what I'm torquing at.  And it has worked very well for me.

Fair enough.  And as far as I'm concerned, post-back surgery posting - that makes sense! - deserves a special award.

Thanks for the head's up.  Just picked one up last night.