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Posted: 12/23/2016 11:58:33 AM EDT
| I tightened the barrel nut tight , then kept going till the gas tube hole lined up I was getting down on it ,I'm a pipefitter and use wrenchs all the time and torque stuff at work to 35 ft lbs I'm pretty sure I got more than 35 ft lbs but didn't use a torque wrench, anyone give me your thoughts you think its ok, anyone else ever just tightened the shit out of one and went with it. |
| When dealing with barrel nuts, you always want to use a torque wrench. The nut that came with my Geissele specified to be torqued to 40 ft/lbs, and a lot of barrel nuts have special instructions about torque to point A, and then unscrewing 1-2 turns, and then torquing to point B. |
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I wouldn't worry about it. I've had some line up at 30ft/lbs and some at 80ft/lbs and they've all shot great. I might be wrong for doing this, but I quit using a torque wrench several builds ago. I've gotten a "feel" for what is right. These guns are my own. If it were my job to assemble guns for others- I would probably still use a torque wrench. |
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I tightened the barrel nut tight , then kept going till the gas tube hole lined up I was getting down on it ,I'm a pipefitter and use wrenchs all the time and torque stuff at work to 35 ft lbs I'm pretty sure I got more than 35 ft lbs but didn't use a torque wrench, anyone give me your thoughts you think its ok, anyone else ever just tightened the shit out of one and went with it. It's fine. If you were "getting down on it" it is likely over 35lbs. Even if it isnt, it's fine. The barrel can be totally loose in the upper and there is no safety issue. If you know it is snug, then there is no issue. If you use a torque wrench much on other things, or if you have stripped nuts/screws/bolts in the past, you can develop a feel for torque values.... 
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I tight to 30 pounds three times, line up gas tube , doesn't fit, I work up to 60 pound if needed. if that doesn't do it......I might go to 70 if I'm almost there...... if it's half way to the promise land ..
Dremel 
Attached File |
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Quoted:
I tight to 30 pounds three times, line up gas tube , doesn't fit, I work up to 60 pound if needed. if that doesn't do it......I might go to 70 if I'm almost there...... if it's half way to the promise land .. Dremel
https://www.AR15.Com/media/mediaFiles/334593/Untitled-112990.JPG Killer artwork lol |
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I tight to 30 pounds three times, line up gas tube , doesn't fit, I work up to 60 pound if needed. if that doesn't do it......I might go to 70 if I'm almost there...... if it's half way to the promise land .. Dremel
https://www.AR15.Com/media/mediaFiles/334593/Untitled-112990.JPG This made me laugh. 
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I swapped a barrel for someone from an A2 to an A3.
I had to hang on the wrench to get it to unscrew. Installing the barrel on the A3 I wound up lightly sanding the face of the upper to get the next hole to line up below 70#. (wrench only goes up to 70) I don't think it's going anywhere. |
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You'll probably be fine. If you're worried, take everything apart, clean it up real good, and do a penetrant test on the threaded portion of the receiver extension.
You're seriously best off using a torque wrench, but even in using a torque wrench, there is a lot of confusion. For example, most of us are using some sort of a crow's foot style of device. Torque is a value derived from the center of the turning axis - in this case, the center of the barrel. So, if we add that crow's foot distance to the length of the torque wrench, it can add considerable torque (12" torque wrench + 2 extension on crow's foot = ~17% torque increase at the nut / 14" torque wrench + 4-1/2" extension = 32% increase in applied torque). So, if you want it torqued correctly, this adjustment needs to be made. But, quite simply, torque (in lb-ft) is the weight applied to a wrench 12" from the rotational centerline. So, if I make a mark on my wrench 12" away from the center of the fastener or barrel, and apply a static load of 35lbs, it's torqued to 35lbs. I know what you're saying about "feel" and I won't argue with you. When I was in training at Fort Knox, my instructors used to get really pissed at me for not digging out a torque wrench - particularly when they checked my work and found it accurate. I just used tape measures and my body weight, quickly figured the ratios, and then stepped on the wrench. Anyway, enough rambling... You're probably fine. Or it may break later. |
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Here's a couple links to calculating the torque offset:
http://www.engineersedge.com/manufacturing_spec/calculator/torque_adapter_extension.htm http://www.norbar.com/en-gb/Home/Torque-Wrench-Extension-Calculator Also keep in mind that there are 2 styles of "extensions". One changes the distance from the center of the rotational axis, and the other does not. Yes, going this far is splitting hairs, given how much room we're allowed to move the nut so it can be indexed to the gas tube. But, I was in my LGS last week, and he had mentioned have a number of AR15's come in with barrel nuts so loose that he could open them up by hand. The other end of the spectrum is tightening it so far that you damage the threads or receiver extension, although not horribly likely. The nut squeezes the rib on the barrel extension against the receiver extension, so stresses should be fairly minimal, but may nonetheless be present. |
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Quoted:
When dealing with barrel nuts, you always want to use a torque wrench. The nut that came with my Geissele specified to be torqued to 40 ft/lbs, and a lot of barrel nuts have special instructions about torque to point A, and then unscrewing 1-2 turns, and then torquing to point B. Geissele can be a lot more specific with their torque values since the barrel nut doesn't need to be timed. Typically, barrel nuts that need timing have a pretty wide torque range. |
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