Should a wet or dry ft-lb value be used when torque-wrenching a barrel into an action?

[Cassidy]

My gunsmith advised me to put a very small amount of aluminum or copper anti seize on the barrel threads (and face where the barrel touches the action) for screwing and torque-wrenching (80 ft-lbs) the barrel into the action. That seems to be working fine. However, I'm curious: for torque values used for screwing barrels into actions with anti seize applied, are they wet (lube applied to threads) or dry (no lube) torque values, recognizing that anti-seize is not lube (I apply no lube, just copper anti seize). I could ask my gunsmith, but thought it would be interesting to ask you all. Any thoughts?

 

[M-61]

Yes, I sure do.
Any time you apply anything to the threads the torque value changes. Look this in any book regarding the % you must deduct from the listed torque ( provided you were given it)
Some substances require a 50% reduction!!
This is invariably overlooked by most people.
BTW 80 lbs/ ft ( correctly called that not foot pounds which is wrong but accepted by most)
seems crazy high to me. But I’m not your gunsmith.
There are official charts for torque values regarding the size of the threaded connection and then the minus % for using anything on them
If 80 was your number and it was done dry do you see what would be the real number?
You used an anti seize so see which one and then what % you deduct.
There are people who have no need for torque wrenches because they have a ‘magical’ built in natural feel.
They would not be working for me or any company I worked for. It’s quite the gift. Backwoods gypsy mysticism.

 

[WildBill3/75]

"Stainless Steel Substrates

Stainless steel substrates pose numerous challenges when it comes to seizure and galling. Using anti-seize lubricants for stainless steel can help minimize many of these issues and facilitate assembly and disassembly a for maintenance and repair.

However, it is important to remember that while many compounds exist for stainless steel, copper anti-seize on stainless steel will create inter-crystalline corrosion which can cause parts to crack or break when under heavy loads."
https://www.henkel-adhesives.com/us/en/products/industrial-lubricants/anti-seize-compounds.html

I've always used grease on threads and been able to pop them on and off with no problems.

To your original question 80 ft/lb torque "wet" should be just fine.... General prefit torque values are all over the place from 30-100 ft/lb.

You can always buy a set of go/nogo guages if you are worried about headspace.

 

[JMayo]

No anti seize on rim where barrel contacts action. Head space will change.
On my br's i snap them on.
never have used a torque wrench.

Smith told me i must have had 100ftlbs on one i leaned on pretty hard !

 

[rijndael]

To your original question 80 ft/lb torque "wet" should be just fine.... General prefit torque values are all over the place from 30-100 ft/lb.

That's my thought as well. With such a wide range of generally accepted values, pick something mid or mid-low, use some grease, and call it good enough.

 

[M-61]

Stainless steel has some strange features. Following from Bolt Science:

Stainless steel can unpredictably sustain galling (cold welding). Stainless steel self-generates an oxide surface film for corrosion protection. During fastener tightening, as pressure builds between the contacting and sliding, thread surfaces, protective oxides are broken, possibly wiped off, and interface metal high points shear or lock together. This cumulative clogging-shearing-locking action causes increasing adhesion. In the extreme, galling leads to seizing - the actual freezing together of the threads. If tightening is continued, the fastener can be twisted off or its threads ripped out.

 

[gunsandgunsmithing]

It might be best to settle this by saying that you should never dry fit the bbl into the receiver, as you are accepting the chance of galling two relatively expensive parts together. Most use anti-sieze but any good hp grease is good. This isn't an area that requires an "anti-seize" lube and isn't one that stresses the capabilities of most any good grease. More is sometimes, just more. Anti-seize is just a good grease with particulate that coats the part if the grease cooks off, preventing seizure.

 

[jelenko]

copper anti-seize on stainless steel will create inter-crystalline corrosion

Arrggggg. I've got copper based anti seize on 5 barrel nuts on ar 15's!

 

[rijndael]

Arrggggg. I've got copper based anti seize on 5 barrel nuts on ar 15's!

I'd check out AeroShell 33MS

 

[GenePoole]

Arrggggg. I've got copper based anti seize on 5 barrel nuts on ar 15's!

AR's are aluminum.

 

[rijndael]

AR's are aluminum.

The barrels may be stainless.

 

[tac284]

Related thread

Grease on barrel shoulders

I saw a video by a gunsmith recommending to not put any grease on the barrel shoulder when torqueing a barrel. I am sure this probably originated from some of the testing done in "rifle accuracy facts". I think its a great book and a lot of effort went into it, but keep in mind the instrument...

forum.accurateshooter.com

 

[gunsandgunsmithing]

Arrggggg. I've got copper based anti seize on 5 barrel nuts on ar 15's!

Isn't that more so with copper and aluminum? Maybe ss, too.

edit...A little googlefoo says both create a galvanic corrosion with copper.
There is a grease called Ox-Gard for use in electrical connections where copper and aluminum are joined...fwiw.

 

[Carl S]

My gunsmith advised me to put a very small amount of aluminum or copper anti seize on the barrel threads (and face where the barrel touches the action) for screwing and torque-wrenching (80 ft-lbs) the barrel into the action. That seems to be working fine. However, I'm curious: for torque values used for screwing barrels into actions with anti seize applied, are they wet (lube applied to threads) or dry (no lube) torque values, recognizing that anti-seize is not lube (I apply no lube, just copper anti seize). I could ask my gunsmith, but thought it would be interesting to ask you all. Any thoughts?

I would never assemble a barrel and action together dry,especially stainless.i always make sure both components are meticulously clean,a little moly grease and torque to 70ft/lb.

 

[jelenko]

The barrels may be stainless.

The barrel nut is steel, but the threads don't engage the barrel. There's a flange that engages the barrel extension.
I've been using the same antiseize for awhile without an issue. But it's grease from now on.

 

[rijndael]

The barrel nut is steel, but the threads don't engage the barrel.

My mistake.

 

[jelenko]

My mistake.

No worries!
The barrel nut does screw onto the aluminum upper receiver. It's what provides the force to push the barrel extension against the face of the upper.

 

[rijndael]

Yea, my AR building days are long past me. It's probably been 10'ish years.

So, my multi-tasking of trying to figure stuff out at work and giving this half of my attention is clearly not working out.

But the AeroShell 33MS was correctly dusted off in my brain. That's what I've used and is generally recommended for barrel nuts by those far more clueful about it than me.

 

[M-61]

That's my thought as well. With such a wide range of generally accepted values, pick something mid or mid-low, use some grease, and call it good enough.

Every now and the I realize how fortunate I am.
I never worked at anything where “good enough “
was even close to being acceptable.

 

[rijndael]

I never worked at anything where “good enough “
was even close to being acceptable.

I'm glad you view it that way, but I don't believe it.

"Good Enough" is something less than perfect, sufficient.



You mow your grass into a perfect checkboard pattern, every week? You measure all of the resulting squares or diamonds to make sure they're all equal? Never skip the weeding/trimming? Clean your car to perfection every time?

Everyone decides that something is good enough, no one has time to make everything perfect.