Loc tite or not?

[VforVandetta]

So i'm setting up my 3 gun rifle....I have a razor 1-10x on a reptilia AUS mount. 

 

I go to start mounting it yesterday, and stumble upon a YouTube vid from Vortex called "10 minute talks - Over Torqued Rings" 

 

By that point I had already mounted my scope base, used loctite on the screws to mount the base to the receiver, and used my Fix it Sticks torque wrench to  crank down the base to 30in-lbs, when to my amazement, I heard them say in the video about how loc tite is unnecessary. It also says this in the manual. In the video they said :  

 

"...That's why you don't need to use a thread locking compound, we haven't used them on any of our rifles around the shop...everything up to 50 BMG..and had no issues, haven't had any screws backing out on us.." 

 

they said that the threads "create a lock them selves, and don't back out"

 

So, realizing that my entire life is a lie, and I that everyone who sends loc tite with their scope mounts, and everyone who sends screws with loc tite already on them and recommends the same 18in-lbs for scope rings and 10-15in-lbs for pistol optics must just love wasting money, I proceed to carefully level my scope, space my rings, and torque them, in a criss cross pattern to 18in-lbs.

 

Today I took the rifle to the range. Shot about 20 rounds...and I got back to check the scope fasteners with the torque rings, again in a criss cross pattern. Sure enough, about 6 of the 8 screws could be moved about 1/16th of a turn to get back to 18in-lbs. I do this anyway whenever I mount a scope and shoot a few rounds, just for good luck, but surprisingly, when I apply loc tite, they don't move even after shooting.

 

I shot about 30 more rounds. Went back with the torque wrench. Criss cross. 3 of the 8 screws could be tightened about 1/16th of a turn. 

 

I shot about 60 more rounds. And left the range.

 

I just went back through with the torque wrench one more time. Criss cross. 4 of the 8 screws could be tightened about 1/16th of a turn.

 

What should I make of this? 

 

In the Manual for the scope it says, "don't use loc tite, but if you do, do not exceed 11in-lbs of force." 

 

The Reptilia instructions say to only use 15in-lbs on the scope rings, and no loc tite. 

 

I am not reassured by any of this right now. Any input welcome. 

 

 

 

 

[IVC]

That's a lot of backing out - if you got 1/16 of a turn after only 20 rounds I would double check your process. Try again and measure after each round. Or shoot 40 rounds and see if you get more backing out. 
 

Loctite is a personal preference. Heed the warning, though, about lower torques if your screws are wet with Loctite. Excessive torque on the rings can damage or affect the scope. Torque on the rails is more forgiving, but there is no reason not to stick to the published values. 

[VforVandetta]

6 hours ago, IVC said:

That's a lot of backing out - if you got 1/16 of a turn after only 20 rounds I would double check your process. Try again and measure after each round. Or shoot 40 rounds and see if you get more backing out. 
 

Loctite is a personal preference. Heed the warning, though, about lower torques if your screws are wet with Loctite. Excessive torque on the rings can damage or affect the scope. Torque on the rails is more forgiving, but there is no reason not to stick to the published values. 

 

Respectfully, what part of my process should I check or adjust? 

 

I mounted the scope using the suggested 18lbs and shot a few rounds of some 2900fps .223....what should I do instead

[IVC]

If you end up with loose screws after only 20 rounds, you have to figure out at which point the screws start backing out. Put witness marks on the screw/mount and watch when they get misaligned. If it changes 1/16 of a turn in 20 rounds, you should see it move round-to-round as you fire. 

 

Alternatively, "checking the process" means that you ensure the torque wrench/screwdriver is in good working order and that you click it properly and consistently. If the screws don't turn but you get to "re-tighten" them, then the problem is with the tool or how it was applied. I'd definitely start with the witness marks and post back in this thread how it goes. 

Edited October 2 by IVC

[Nolan]

When using Loctite or any lubricant on threads, reduce the torque by 25%.  Reptilia specifies a torque of 15 in lbs Dry.  If you are using Loctite, reduce the torque by 25% ie. tighten to 11 in lbs.  With Loctite you've tightened the screws to the dry equivalent of 22.5 in lbs.

 

Also important with Loctite, the cure time, without primers or accelerators, is 24 hrs at 70+ degrees to fully set up.

 

Read and follow the instructions for the product you are working on, not the instructions for some other product.

 

Nolan

Edited October 3 by Nolan

[mpeltier]

who came up with reducing by 25%? if you use locktite. If the Locktite is wet and not partly hardened, how is that different than if the screw has oil on it, which most screws do from the package. If its factory applied locktite on a screw, you may not be able to get it tight at the recommended torque.

 

My process, and I do this for a living at a LGS, Is freshly applied blue locktite and torque to recommended torque values. I have mounted hundreds of rings/mounts over the years and have not broken or stripped one.....ever. Additionally I have never had a customer complain about a loose scope/mount.

 

The only time I reduce the torque value is rails mounted to aluminum receivers such as a Ruger 10/22.

 

In Lbs is a very minimal amount of torque, super light. Most quality screws and steel receivers can take much more than the 12-25 in lbs that is recommended for most of these applications. If you are not using a torque tool/wrench and doing it by feel with the little hex key many supply, you are probably grossly over torquing any way.

 

The most common problem to come in my door is when somebody does it at home by cleaning the screws and screw holes and putting it together DRY. Then wonders why after 3 seasons in the Florida humidity their screw(s) broke off when the tried to remove it.

[IHAVEGAS]

"In God we trust, everyone else must bring data" - Author unknown. 

 

Always liked that quote except when it was used against me  . Regardless, has anyone ever seen a problem caused by using loctite at the manufacturer's recommended torque specification? Not talking about a 'can't get it loose without heat' problem, talking about a deformed due to excess torque problem. 

 

When I looked into things a long while back I came away with the understanding (perhaps wrongly) that threaded surface friction tended to vary significantly from piece to piece and that where things were really critical measuring bolt stretch was employed if possible. 

[dtuns]

I just mounted a Vortex defender and the instructions said torque to 15 inch lbs dry or 12 with loctite.

[kurtm]

I'm with Mr. Peltier on this! And at the minimal torque we are talking about it would almost be impossible to "bend" a scope tube. Not talking ring misalignment, I'm just talking about constricting down on a round tube, unless you tube is so thin walled you could see the lenses through it

[WS6]

On 10/7/2024 at 11:03 AM, kurtm said:

I'm with Mr. Peltier on this! And at the minimal torque we are talking about it would almost be impossible to "bend" a scope tube. Not talking ring misalignment, I'm just talking about constricting down on a round tube, unless you tube is so thin walled you could see the lenses through it

 I will usually get 6-12 thou compression out of a scope tube (depends on manufacturer). I measure ring gaps on both sides during the process.

[Joe4d]

Throw some blue loc tight on them ( I use the paste stick) snug them down with a screw driver or allen wrench,, call it good.