How much torque on barrels

[Grimstod]

Lol. Don't tell me someone has tried that. :

The philosopher Descartes once said. "No idea is so stupid some philosopher hasn't tried to teach it."

 

[carlsbad]

As for lubricants, there is not much difference in their effect on the clamping force. High quality threads such as those single point cut barrel threads and quality action threads are going to have very little friction and lubricated threads are even slicker. In fact, in my previous post about torque I used the formula T=.2FD. The .2 is the "nut factor" and .2 is generally used for commercial threaded bolts. But thinking about it last night as I did the calc for someone who PMd me, I decided to use .12 for lubricated threaded barrel joints with their high quality threads.

So if any lubricant works, why do we care? We care because someday we'll be taking the joint apart and we want something that won't turn to glue when it dries out. this is especially important in this joint since it can get quite hot in a range session. I don't know how hot but 300 to 400 degrees can severly degrade many oils.

So I use nickel antiseize designed for power plant applications where pipes can get to 800 deg F.

Here is the one I put together yesterday next to a 26" heave Remington Barrel.


--Jerry

 

[carlsbad]

PS. I see some concern that the anti-seize is not a good lubricant. The nickle antiseize I use is a pretty good lubricant. Not sure what others are using but if they aren't a good lubricant, then the torque can be increased. The nut factor is linear in the formula above. If you assume a lubricated joint in .12 like I did then use a .2 factor for the antiseize. This would mean increase the torque by .2/.12=1.83 so increase torque by 80%. Can't really think it would be that bad a lubricant so perhaps a factor of 1.5 would be better.

But I'm thinking most bolted joint anti-seize is a pretty good lubricant. Is someone thinking about pipe joint antiseize which is also intended to fill gaps and prevent leaks?

--Jerry

 

[butchlambert]

So you think a synthetic grease will dry out? Jerry, I have used my infrared thermometer on some PD rifles that were severely hot and they were 190 degrees. I'm not saying that your premise is wrong, I just don't think it is the only answer.

 

[NYM]

I would like to apologize for my outspokenness. I do want to learn from people who have knowledge in the shooting world. I'm open minded till some one starts cutting on me - I was told one time a closed mouth doesn't get feed. I tried and told you who I am - no one else has said boo as to who they are or what they do. I'll ask this as careful as I can -- how come no one here has the same torque specs that are spoken? I'm not saying there wrong but for the caliber people here - 2 people should say the same thing. The one thing that got me real pissed is no on has said " Bat or Panda [manufacturer] says to tighten this new receiver like this. Or Shilen or Bartlein [manufacturer] says to tighten there barrel like this. You all just put up numbers with no verification as to where they come from. You have to understand - as you folks are precision shooters - I try my best to be as precise as I can at any thing I do. Torque in my world is a specific number - [85 lbs +or- 5% and in machining its 1.250" +or- .005]these are just generic numbers for the type of precision I work with. I'm sorry but it bugs me bad when someone has a 100% deviation in there numbers or a group of professionals in the same field don't speak the same thing.
Just so you know the numbers that were in the first post are not right. I don't use an 8 ft cheater - I use a 60" cheater tube. The required sweep on a 10 ft cheater tube would be 12ft 6in for a 1/4 turn and 6 ft -about 3.5 in for an 1/8 which is not possible in a shop with an 8 ft ceiling or by me. The required sweep with a 60 in cheater would be 7.85 ft for a 1/4 turn and 3.925 ft for an 1/8 - I have never tightened any barrel that tight. But a 2 ft sweep or about 27 degrees I do -- right or wrong I can not be faulted for not putting it back the way I found it.
I have written Sako a letter to find out the facts of how to torque a Mosin barrel, the old way and what they would do now in 2014 if they were to make such a piece. Sako was established in 1921 for the purpose of building and servicing Civilian Guard firearms. Which to my knowledge were Mosin Nagant captured rifles. This may not be all they made. I've ask them to help me get this right, The Finn's have IMO some of the best rifles [please don't whip me] - they produced the best Mosins on the market.
If there is some one here that would help answer some questions I have - I'd like a one on one conversation via PM. In my first posts I said I was not in your league and will never pretend to be. I'm sorry to have caused a issue as I only responded because the numbers in the first post were not correct. I'm open to any information that can be verified -- remember like the earlier post said"if its on the Internet its gotta be true".

 

[Jay Christopherson]

I would like to apologize for my outspokenness. I do want to learn from people who have knowledge in the shooting world. I'm open minded till some one starts cutting on me - I was told one time a closed mouth doesn't get feed. I tried and told you who I am - no one else has said boo as to who they are or what they do. I'll ask this as careful as I can -- how come no one here has the same torque specs that are spoken? I'm not saying there wrong but for the caliber people here - 2 people should say the same thing. The one thing that got me real pissed is no on has said " Bat or Panda [manufacturer] says to tighten this new receiver like this. Or Shilen or Bartlein [manufacturer] says to tighten there barrel like this. You all just put up numbers with no verification as to where they come from.

As you are pretty new here, you've missed out on the several thousands or 10's of thousands of threads where that stuff has come up... It's sort of incumbent on new members to figure out who they are talking to, rather than expect everyone to re-present their credentials every time a new member joins. I'll give you a hint - there are some very experienced people who have chimed in on this thread and their experience has been presented quite often in various places, not necessarily limited to this forum.

A manufacturer will quote you a number that is "safe" - that is, presents little to no liability for them, but is not necessarily the best option. Similar to how Remington sets their triggers to something like 8lbs from the factory for liability purposes (and will flat out tell you not to modify it), yet we *all* use far lighter trigger weights. Experiential testing has shown that there are many safe and effective torque numbers out there (same with trigger pull weights), which is what people are trying to help you understand.

A closed mouth doesn't get fed - but it catches no flies either.

 

[carlsbad]

So you think a synthetic grease will dry out? Jerry, I have used my infrared thermometer on some PD rifles that were severely hot and they were 190 degrees. I'm not saying that your premise is wrong, I just don't think it is the only answer.

No, I'm not saying it will and perhaps synthetic grease is a good solution. I just have experience with the Nickel Antiseize. Also, 190 degrees isn't that hot. So maybe I'm worrying too much about it. But old rifles that don't come apart easily probably should have used something else. I'll look into synthetic grease for my own use. --Jerry

PS 190 on surface means quite a bit higher at the threads so I would stay away from convention greases that separate with heat.

 

[butchlambert]

Jerry,
You might want to check the tech specs of my Prolube 1000 PPL-1 lube. Being a synthetic the usable temp range is -10degF to +450deg F. My only complaint with the anti seize is the gritty feel. It may be the cat's meow. I switch barrels a lot and the Bat Receiver I use most shows no change in headspace with the different barrels that I feed it. That is for my PPC and 30BR. I rebate the rims on my BR cases inorder that I can use the PPC bolt on my 30BR.

 

[Grimstod]

So talking about vague. Check out what these guys say about barrel torque.

"a Remington Model 700 action should be torqued to somewhere between 35 and 300 ft/lbs,"

You can find the entire article here. The quote above was on paragraph 23.
http://www.realguns.com/articles/328.htm

They selected 100lbs but looking at the tool they use I don't think I would want to be twisting that part of the receiver like this.

 

[butchlambert]

Grimstooge, I didn't read it, but what is the recommended torque? Quite a range that you posted. Did this come from your law in management classes?
Sorry, I couldn't resist.

 

[Grimstod]

lol. No offence taken ;D

It's not a range I recommend I am not knowledgable there. That is why I started the post asking about this. I would be a little more specific. I think he steels on 100 lbs in the next paragraph.

 

[BigDMT]

Can we all just agree on 40 lbs and close this case?... :-\

OK great, case closed

 

[NYM]

Can we all just agree on 40 lbs and close this case?... :-\

OK great, case closed

Fine by me. Thank you all and I will experiment with what I've learned here.

 

[snakepit]

Now I have a friend who is a self taught gun smith.

The problem is that your friend had a fool for a teacher.

Words of wisdom. +1

 

[jscandale]

Wow, 7 pages on barrel torque....
Here's an option, just torque it on until the threads start to strip and back off just a hair and call it good! 8)

JS

 

[Macropod]

This reminds me of an apprentice I had who would come to me saying "I think something is wrong.... when I tighten this bolt up it gets sort of tight then loose then a little bit tight...". :

 

[Keith Glasscock]

So talking about vague. Check out what these guys say about barrel torque.

"a Remington Model 700 action should be torqued to somewhere between 35 and 300 ft/lbs,"

You can find the entire article here. The quote above was on paragraph 23.
http://www.realguns.com/articles/328.htm

They selected 100lbs but looking at the tool they use I don't think I would want to be twisting that part of the receiver like this.

About that photo - I wonder how they set the torque wrench. Do they take into account the extension of the action wrench? Yes, I know the formula... Just wondering...

 

[JRS]

Why would anyone want to go beyond a snugged up fit anyway? Once that has been accomplished, you certainly aren't going to remove the barrel with your bare hands, nor is the barrel going to somehow work it's way loose.

 

[stool]

i believe the spec is 35-45. cycle the torque 3 times and a LITTLE more is allowed to align the gas tube.
i think the 125 number is for the bbl extention to the bbl

You will do neither the barrel or action any good using more than about 40# of torque. Will it ruin them? Probably not but it certainly isn't necessary or needed. A situation came to my attention recently when an AR "expert" tightened the barrel nut to 125# & shearing the locating pin off of the top of the barrel extension. Guess whose fault it was? The barrel manufacturer gave him a faulty barrel according to him. You risk twisting the reciever in my opinion.

 

[stool]

well being the guy that like to toss the wrench in the gear box.....

with all you guys and all your comments
i have seen nothing that addresses the stress put on the joint during firing.

how much torque is need to ensure the joint is not upset by firing ?

( ps if i remember correctly, on the typical 16 x1.0xx it was 125 ftlbs)

this is not a friendly torque for those that switch bbls alot, but not so high that it is not easily obtained)
think about it , just around half your wieght on a 12" wrench.

and again mn's can be made to shoot very well with oem bbls that are in excellent condition.
is 3 shot groups under 1/2 at 100yds decent for a 70 yr old rifle ??