How tight is 35 ft pounds of torque?

[Rockrivr1]

I finally received the new Advanced Half Quad forearm from RRA for my LAR-8. I ordered it in January and it arrived today. Wow that was quick. It's this one.

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=410

Now that I have it, I'm going over the instructions to install it and I don't have any of the "required" tools. I believe I have tools that will work to do the job, but as typical I'll be winging it as I go.

It tells me I need to tighten the barrel nut to 35 ft pounds of torque. Sounds good except no torque wrench so I'd have to wing it. Hence my question. How tight is 35 ft pounds of torque if you had to "wing" it?

You know, I'm always willing to try to do work myself. Having it come out correct is alway a 50/50 proposition though.

 

[FLHTC]

I have one you can borrow. I'm on the south shore

 

[44marty]

It's a straight multiplication. 35 ft lbs is 70 lbs at 6" and 17 1/2 lbs at 24" - Just borrow a torque wrench to be sure.

 

[Jose]

Dude a man should have tools, including a torque wrench.

 

[HiggityHank]

Even a beam wrench is better than no torque wrench, don't "wing it" unless you want to "replace it."

If need be, I'll let you borrow one of mine.

 

[PaulD]

35lbs is in the range that you probably wouldn't over torque it but definitely could. Get a 3/8" torque wrench. They usually do from 15 to 100 ft lbs (for an average one you'd find at HD).

 

[yanici]

And I thought torque wrenches were only for cars.

Funny that this comes up. I needed a torque screwdriver to tighten the screws that hold the action in my Savage rifle. This is an inch/lb. tool. A decent one is mucho dinero. Luckily I found a used Utica TS-30 on Ebay. It had recently been calibrated by Utica, cal. sticker was attached. Retail was about $250. Used was $50 + shipping.

 

[pernox]

If buying a torque wrench is out of the budget, get a sixer of PBR and bring it to the closest auto shop. I'm sure you'll find someone to spend a couple minutes torquing it properly.

 

[GaryO]

Would you "Wing" a reload? Be smart and use the right tool for the job. Its a rifle not a '72 valiant.

 

[Arto]

Like on Spark Plugs: Tighten it until it strips, then back off 1/4 turn & pretend you didn't do it.

 

[LoginName]

Try Auto Zone. They should have a loaner/rental torque wrench at no charge.

 

[Ink]

20 is usually considered a little more than finger tight ( i believe most spark plugs were "supposed to be" torqued to 20. 35 is not very much. Also, depending on the finish of the bolt ... some bolts are torqued lubricated, some are torqued dry (hence certain types of zinc coatings on bolts)

Definitely go with a 3/8 drive torque wrench.... one that has inch/lbs increments would probably be even better.

 

[vicpinto]

I torque all by crap to German specifications.

Good-n-tight

 

[daveyburt]

Like on Spark Plugs: Tighten it until it strips, then back off 1/4 turn & pretend you didn't do it.

amen....then sell it

 

[Supermoto]

If is a barrel nut for an AR, you can hand tighten it, then line up the next gas tube hole, usually the barrel nut specs are from 30-75lbs. Not sure if the your LAR-8 is different

 

[daveyburt]

up to 20ish ft/lbs is wrist tight

up to 50 is elbow tight

over that is shoulder tight.

but, buy a wrench.

 

[wannabmudn]

35 is about half a grunt

 

[goofycj7]

Depends on the size of the wrench/ratchet/breaker bar you are using. If you are near Southbridge or Spencer I have a Torque wrench you can borrow.

 

[boilermaker]

I have one in my truck you can borrow. I am in Southbridge, which I consider south Central Mass, where are you? Incidentally 35 lbs - not that tight at all

 

[EddieCoyle]

Would you "Wing" a reload? Be smart and use the right tool for the job. Its a rifle not a '72 valiant.

C'mon. Putting a barrel on an AR and making ammo are two completely different things.

First of all, 35 lb/ft is likely the minimum that he'll have to torque it. He'll get to 35, then have to line up the next hole for the gas tube. I've had to go all the way to 80 lb/ft to get the next hole to line up. As long as he gets the minimum (which is as low as 28 according to some people) the rifle will be fine.

Supermoto has it right - snug it up, then line up the next hole.

 

[edin508]

35 is about half a grunt

I was going to say 1 grunt.

 

[CRSIII]

I was going to say 1 grunt.

Have you met wannabmudn?

 

[edin508]

Have you met wannabmudn?

LOL
OK, 1 grunt for a 5'10" 180lb. guy

 

[rattletrap1970]

+1 It's a rifle not a '72 Valiant. Holy crap that was funny.

 

[Amicus]

+1 On EddieCoyle's statement, with a couple of notes:

1. Get a vise block, really. This is the best way to install a bbl nut without crushing or marring the upper.
2. If you get to snug at one gas tube hole, then go for the next one. If you have more than 1/2 a hole diameter to go, then "work the threads" by tightening and loosening -- you will slowly get close to the target hole. When you have less than 1/4 of a hole diameter to go, tighten it down, but don't go past the target hole (I have, potentially a problem).
3. Put some molly grease or wheel bearing grease on the threads before you tighten, not a lot but enough to cover the threads to prevent galling.
3. 30-80 ft lbs is the army spec for tightening a standard bbl nut. Try to go with the instructions.

 

[MetalgodZ]

+1 On EddieCoyle's statement, with a couple of notes:

1. Get a vise block, really. This is the best way to install a bbl nut without crushing or marring the upper.
2. If you get to snug at one gas tube hole, then go for the next one. If you have more than 1/2 a hole diameter to go, then "work the threads" by tightening and loosening -- you will slowly get close to the target hole. When you have less than 1/4 of a hole diameter to go, tighten it down, but don't go past the target hole (I have, potentially a problem).
3. Put some molly grease or wheel bearing grease on the threads before you tighten, not a lot but enough to cover the threads to prevent galling.
3. 30-80 ft lbs is the army spec for tightening a standard bbl nut. Try to go with the instructions.

Most complete info yet. +1 on step 2 and especially step 3. And the moly goes on before YOU tighten it.

That said...

Dude a man should have tools, including a torque wrench.

Seriously.

A Wal Mart torque wrench is $25 on sale and hasn't failed me or been more than maybe 2-3% off from my friend's Snap On wrench in the 5 years I've owned it.

 

[Rockrivr1]

Jist of most posts - Get my own damn torque wrench! Ok, I get it. Thought they were a little more expensive then $25 at Walmart, which is why I've never bought one. I do have tools. Just nothing specifically for firearms. I think I can manage. Otherwise my next post will be how I scratched, dented, broke, dinged, etc' my LAR-8.

Thanks to everyone who offered to let me use or borrow theirs. I may still take you you up on that depending on when I do this and the cash situation. I have an AR15 vice block, but it doesn't fit the LAR-8 which is basically an AR-10 type design. Armalite has one for $40, so I may get that one.

Thanks again for the information.

 

[radioman]

35ftlbs is equal to applying 35lbs to a 1ft wrench to put it in a simple form. You could also say that 35ftlbs is enough energy to lift a 35lb weight 1ft at sea level.

So in a pinch with out a torque wrench I would find a 1ft wrench measured from the center of the fastener to the point where I attach my fish scale. Pull your fish scale perpendicular to the wrench until it reads 35lbs. You now have applied 35ftlbs to your fastener in a crude way.

 

[zerodown]

Finger tighten the barrel nut and give it three good torques with the wrench. Line up to the closest hole (forward or back). Thats about 40-45lbs worth

 

[Boghog1]

My shoulder pops at 80-85ftlbs, my elbow 45-50ftlbs and my wrist at 25-30ftlbs