AR Sponsor
Posted: 7/28/2010 10:42:38 AM EDT
| Can someone please explain to me how to use these? I don't have any experience with them, and I always hear about torquing the barrel nut 3 times to a certain spec, as per the TM. How do you know how much torque you're getting? Thanks. |
|
You could probably google this for a better explanation.
It depends on the type of torque wrench you have...some are adjustable and you "crank" on them until they "break" at the desired torque which is set (usually) by twisting the handle (grip)...there will be a vernier on the shaft of the wrench and as you turn the handle it moves up (down) the shaft. Other (cheaper typically) ones have a scale with a needle...as you torque, the shaft bends, the needle points to the torque on the scale. Is that what you were looking for or is it the torque-untorque-retourque process? |
|
Quoted:
You could probably google this for a better explanation. It depends on the type of torque wrench you have...some are adjustable and you "crank" on them until they "break" at the desired torque which is set (usually) by twisting the handle (grip)...there will be a vernier on the shaft of the wrench and as you turn the handle it moves up (down) the shaft. Other (cheaper typically) ones have a scale with a needle...as you torque, the shaft bends, the needle points to the torque on the scale. Is that what you were looking for or is it the torque-untorque-retourque process? Both of you answered that beautifully. Now I would also like a better understanding of the torque-untorque process. I read the FAQ multiple times, but I can't seem to square it away in my mind. |
|
Quoted:
Quoted:
You could probably google this for a better explanation. It depends on the type of torque wrench you have...some are adjustable and you "crank" on them until they "break" at the desired torque which is set (usually) by twisting the handle (grip)...there will be a vernier on the shaft of the wrench and as you turn the handle it moves up (down) the shaft. Other (cheaper typically) ones have a scale with a needle...as you torque, the shaft bends, the needle points to the torque on the scale. Is that what you were looking for or is it the torque-untorque-retourque process? Both of you answered that beautifully. Now I would also like a better understanding of the torque-untorque process. I read the FAQ multiple times, but I can't seem to square it away in my mind. You tighten (just snug) then loosen it three times to get everything seated nicely ... then set the wrench to 30-35lbs and ratchet the nut until the wrench clicks ... check the gas hole alignment between the barrel nut and receiver if it's not aligned then loosen and increase torque value a little and repeat until it's aligned ... just don't go over 80lbs. |
|
Yep, the process is just that simple. Tighten the nut down then loosen it up at least 3 times, then on your 4th try, tighten it until the nut lines up so the gas tube can slide through. The first 3 times, tighten to at least 30 ft. lbs. The last time tighten to at most 80 ft. lbs. You may have to do the first part several more than 3 times to end up with the nut lined up for the tube at less than 80, or you may hit bingo on the first go-round.
If the only reason you are buying a torque wrench is for your AR barrel nut, the cheaper 'beam type" wrench is plenty good enough. Some jobs in life require a very accurate torque wrench, but an AR barrel nut is definitely not one of those jobs. |
|
Quoted: If the only reason you are buying a torque wrench is for your AR barrel nut, the cheaper 'beam type" wrench is plenty good enough. Some jobs in life require a very accurate torque wrench, but an AR barrel nut is definitely not one of those jobs. This - you can usually find a decent beam torque wrench in any pawn shop. Just look for a brand you know and in good shape. I got a Craftsman, virtually unused for 10$. AR build can also be done without this tool, it is not mandatory. |
|
Maybe this doesn't apply with AR barrel nuts (since people here are saying the torque isn't super critical), but in general:
The torque specified is for torque while the nut is rotating. Meaning: the nut needs to be rotating as the torque wrench clicks, otherwise you don't have the proper preload on the bolt. It has to do with sliding friction being less than static friction. |
|
The beam wrench works great for ARs. Craftsman brand are cheap and have a lifetime warranty (as long as Sears stays in business I guess).
The amount of torque needed is dependent on where the nut lines up, not a predesignated setting. After you torque it down to about 30 lbs three times on the next one you go past 30 pounds until the next groove in the nut lines up in the receiver gas hole. The amount of torque needed is determined by where that alignment occurs. As long as it's over 30 and under 80 it's good. This measurement is so broad that as long as the nut and hole are aligned you will most likely be in range and the reading on the beam wrench is just reassurance. A Shuster gauge makes alignment a breeze - it fit's and it's right or it doesn't fit and it is wrong. So, for me the beam wrench works a little better than the click type, but the Schuster gas tube alignment gauge is more beneficial then either, although I use all three at different times. I find that the more important torque wrench on AR's is an inch pound torque driver like the Wheeler Fat Wrench. This will give consistent settings on sights, optics, gas key screws, gas block screws, etc. |
|
im not one that usually bashes no name brand tools. but i would never touch another craftsman or no name torque wrench again. and craftsman ones are not "lifetime warrenty". i finally broke down and bought a half way decent snap on one (was only like 500 bucks) and the snap on dealer has a torque gauge on their truck. yeha i tested my crafstmasn one that was 5 months old........ i had it set at 50 lbs........ when it clicked it read 75 lbs on the gauge. tried the snap on one and was right on the money.
so i went to sears and tried to get a new one because it was so out of spec and they told me it only has a 90 warrenty and without a recipet i was S.O.L. and dont use auto parts torque wrenches either. my buddie used one to bolt on his valvebody on a turbo 350 and the spec was 13 foot lbs. so wanting to be careful, he went and got an auto parts one and proceeded to strip a bunch of the hole in his trans. so as far as barrels go at the last step just make sure its good and snug then go till it lines up. just my 4 cents. |
|
Poster above leads to a point worth knowing - click-type torque wrenches have to be periodically recalibrated. I would personally never expect a click wrench on a parts store loaner shelf to be anywhere close unless I watched them unwrap it from its original packaging.
If you want to borrow a wrench, borrow a beam wrench. |
|
Quoted:
Quoted:
Quoted:
The beam wrench works great for ARs. Craftsman brand are cheap and have a lifetime warranty (as long as Sears stays in business I guess). Untrue. 1 year warranty. but only 90 days on calibration!!!!!!! The point wasn't really to debate Sear's warranties, but since you want to discuss it..... "If for any reason your Craftsman hand tool ever fails to provide complete satisfaction, return it to any Sears store or other Craftsman outlet in the United States for free repair or replacement. This warranty gives you specific legal rights and you may also have other rights which vary from state to state." Our Craftsman Hand Tool Lifetime Warranty is one of the most important competitive advantages we have in the market. It is crucial that we ensure all of our sales associates are trained to understand all the hand tools that are covered under this warranty. My post was referring to the particular beam style Craftsman Wrench I use for AR's. It is warrantied under the Forever Full, Made in USA warranty just like their hand tools. It is not considered a specialty tool that carries the warranties you guys are talking about. If your interested look at this product description. I specifically chose it from the display because it has the lifetime warranty and others sitting right next to it didn't. It has been pointed out that working on an AR barrel nut does not require exact, precise, expensive torque measuring devices. This one is more than adequate for this purpose and it has a lifetime warranty (or until Sears goes out of business). |
|
true we were getting off topic. my point is, i dont even use a torque wrench for that part. like i said just make sure its snug and then go till it lines up and you should be fine.
i was trying to point out that if torque specs are important for something you doing then they are important enough to use a quality torque measuring instrument. wich reminds me of another friend (ford probe turbo) he was doing a head gasket and used a cheapo torque wrench. two months later the gasket let go. he did it again and this time borrowed my new snap on one and a year later its still going strong. it was enough of a differenc that he said he could actually feel the difference in torque between the two, wich leaves me thinkin the cheapo one must have been way out of spec. i own a lot of snap on tools (prob @ 40k worth) and i never bash my friends useing craftsman and pittsburgh etc but the one thing i did notice a diff in is torque wrenchs and air tools. |
|
Honest truth, you really do not need a torque wrench. If there was ever a rifle that is riddled with over-thinking and uneeded double checking....it is the AR-15.
With a armorer's wrench, get the barrel nut nice and snug then try to get it to the next possible hole. If you still need a torque wrench for some other part on the AR (which I have yet to guess where) then the pointless debate on warranty has holds some ground then. |
|
You do it the same way leonpiper and gargemel are talking about in the above posts. Tighten loosen three times, then tighten by hand as much as you can, use the wrench to get it to the next gas tube hole. This will result in the range they give.
YHM only recently added the torque to some of their instructions. Prior to this the instructions said do it as stated above. |
|
The craftsman wrenches have a life time warranty, but this doesn't include calibration. If it breaks in a manner where calibration is lost, you are on your own. I'd be happy with one for casual use. If you need accuracy, go with Snap On, Proto, Utica or CDI (owned by snap on). I'm not a huge fan of snap on (as regards their price vs value), but they own the "calibrated" torque wrench market, at least in the range between one ft pound and hydraulic wrenches.
I'm not a gunsmith, so I'm not sure which applications require precise torque. |
|
Quoted:
I just bought an aluminum YHM free float tube with the barrel nut permanently installed in the tube. The instructions say to tighten it to between 40 and 80 ft lbs with a strap wrench. How the heck do you guage the torque with a strap wrench   My strap wrench has a 1/2 inch square hole in the handle to accept 1/2" drive tools. You mean... yours doesn't? ETA: the YHM instructions don't actually say "tighten it to between 40 and 80 ft lbs" From TFM: (8) Using a strap wrench, tighten the forearm to the next aligning gas tube hole in the forearm. NOTE: TORQUE SHOULD BE 40 – 80 Ft. Lbs. That's not quite the same thing. |
AR Sponsor