Loctite torque value reduction? AICS

[NICKNICK]

When using loctite, do you reduce the amount of torque applied vs. the specified amount?

I've heard rules of thumb like a 10-15% reduction, and I know some people don't do any reduction at all.

How much would you reduce the torque value on action screws on an AICS?
Should you even be using loctite on action screws? It seems like a good idea to me, but maybe there are issues I'm not foreseeing.

For those that don't know what I'm talking about, it was counterintuitive to me as well the first dozen times I heard it: Torque, in this case, is just a measurement of how hard it is to turn the screw. What we're REALLY looking for is clamping force. The loctite acts as a lubricant when wet and makes the screw easier to turn, which means you'll get the SAME clamping force at a LOWER torque value.

 

[jbell]

Re: Loctite torque value reduction? AICS

This is very true as it does reduce the resistance required to rotate a fastner and there by you should reduce the torque. However is you are using 35-45lbin or so on them you will have no issues and can just set the torque wrench up to your desired value.

 

[E. Bryant]

Re: Loctite torque value reduction? AICS

According to Henkel, it is generally not necessary to adjust tightening torque values when using Loctite.

That being said, it is not generally necessary to use Loctite on properly-torqued action screws.

 

[mstephenson51]

Re: Loctite torque value reduction? AICS

+1. Generally dont need loctite on action screws.

So, to walk ya thru what I do with the stuff is this: Keep it mission critical, stuff that is life required. Dont use it if you really dont need to, it just gets messy. Purple on stuff about #10 and smaller, Blue #12 to 3/8, Red anything 1/2 and up that isnt going to be removed in the next decade. If it sees vibration, abuse, and you have to keep it attached or ya die then use loctite. If its like most gun parts it doesnt see a lot of vibration and Does see a bit of heat. Heat breaks down loctite so it defeats the purpose.

Enjoy!

 

[NICKNICK]

Re: Loctite torque value reduction? AICS

You're right--I just checked the instructions/data sheet from Henkel, and it says no on-torque adjustments needed. That surprised me because a few years ago a Loctite rep is the one who taught us about torque value reductions when using Loctite. That was during a "brown bag" seminar where we pack a lunch and take mini classes to try to learn something relevant to our jobs. Oh well, sales reps don't always know everything.

Thanks for the tip.

 

[NICKNICK]

Re: Loctite torque value reduction? AICS

I guess I can get behind the idea of a gun not seeing lots of vibration because there's no constant hum or anything, but the recoil impulse seems like something that could loosen screws. I'm not basing that on anything--just intuition.

Do you agree/disagree?

 

[E. Bryant]

Re: Loctite torque value reduction? AICS

Loctite works as a band-aid when it is not possible to obtain tightening torque/preload sufficient to prevent the fastener from walking out. A good example would be scope rail screws. Action screws can usually be tightened sufficiently to avoid unintended loosening, so they would normally not have threadlocker applied.