Torque on scope mounting

S

Sniper66

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Location
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I mounted a set of Talley rings on my Anschutz 1517MPR. During my last p-dog outing the scope worked loose.
www.talleymanufacturing.com

Anschutz Scope Mounts for Drilled and Tapped Receivers

Made in America, these Anschutz Scope Mounts made by Talley Manufacturing offer a unique and simplified one-piece scope ring and base
www.talleymanufacturing.com www.talleymanufacturing.com

I've used this type ring on 3 Anschutz. On one occasion I twisted too hard and broke the screw, thus requiring it to be drilled out, which is why I was timid when I mounted this scope and didn't get the screws tight enough. Now I have a torque wrench, but cannot find specific guidelines. The Talley site says 17-20 lbs of torque for the cap screws, but say nothing about the base. Would it be the same?
 
Found this on WBYs sight in relation to the Talley Lightweight rings: 17-20 in/lb on ring and base screws.

Talley says dis.....Base screw torque can depend on the receiver. Please check with the rifle manufacturer or call us for recommended torque. Always make sure your torque wrench is calibrated, Talley Mfg is not responsible for damage caused to scopes due to over torquing.

Personally, I use 18in/lb on all of my base screws, with Loctite. I've had a few come loose when I've forgotten the Loctite, so dry id probably go 20.

(sorry kept hitting the post button before i finish my thought......)
 
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I use 18 - 20 inch pounds on the base screws and the rings. I degrease the holes in the receiver and use blue locktite on the base screws but not on the ring screws. I use 40 inch pounds on the cross bolt on the rings, if its that type of ring.

Remember, this is INCH POUNDS not foot pounds. I bought my torque wrench from the company that makes Snap On's torque wrenches. It was fairly expensive but so is everything that I use it on.
 
a torque tool is a good idea, but remember 99% of the time, you just get a bolt where you can feel it come up kind of tight/snug, and then you turn it 1/4 or 1/8th turn from there to finish and the threads are a press fit they aren't going to work loose, but loctite is a good idea. for small bolts like on a scope ring, if you find yourself using force to tighten them, it is too much. I basically did the same thing as you once, but I got lucky and the head of the screwdriver bit snapped off before the bolt for the scope ring.
 
Below is the response from Anschutz of North America. But, I'm not going to go that heavy. I'll follow lightman's recommendation of 18-20. I use a Smart-Torq tool and it works fine. This time I'll use Loctite. Thanks for the help.

Thomas,

For the rings to receiver screw I would suggest 25-28. The 6-48 screws don’t like to handle much torque before the heads pop off. Loctite is perfectly fine.

Best Regards,
Austin Cook
 
Fastener torque settings, regardless of the application, depend on a couple of things- fastener type, size, material, hardness grade, and the object being threaded into. This information may help. From Wheeler.
 

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Screw Torque - is a mechanical thing, and not an arbitrary number.

A couple of things need to happen.
- Good contact between the threads.
- Deflection(bending) of the threads.

If the torque "spec" is reached without either - then the screw will vibrate and come loose.

Steps to achieve screw torque:
- Grease the threads
- Grease the head contact area
- Torque to refusal.

Antithetical, but it works.

The screw torque curve is asymptotic - adding torque while reducing rotation.

Unlubricated, Friction can produce the torque spec, without ever achieving thread deflection.

Lubricated, friction is mitigated, so that one can hit the thread "wall," and then rapidly increase torque as the threads deflect and rotation diminishes.

Screw Torque - is achieved when adding a reasonable amount of torque past refusal - produces little or no rotation.


The added advantage to grease is that, as a film, it acts almost like rubber,

It increases the contact area between the threads, and then keys into the pores of the metal, locking them in against vibration.

Also seals the threads from intrusion, protecting them from corrosion.

This works for scope caps and bases, as well as diesel engine mounting and accessory attachment bolts.

Threads are threads.
 
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Many don't like it, and a couple have
even called me unwholesome names,
but I put loctite on everything
When I'm mounting the base, a bead
of loctite goes between the gun and
the base, on the screws for the base,
on the bottom of the rings between
the base and rings, inside the mounting
surface of the rings between scope
tube and rings, and on all ring screws.
I DON'T WANT ANYTHING COMING
LOOSE !
It sucks badly to realize an hour into
your hunt that your scope is loose,
or even worse after you've flubbed
a shot at your intended game

I read posts everywhere about it
happening, so there's no doubt
that it does
 
Here is the problem I see when people look up torque specs. Most torque specs are given for fastening steel to steel. And you don't want to use torque specs for steel to steel when fastening other types of material together. Go with the torque specs from the scope ring/mount manufacturers. And the torque values for aluminum is lower than steel. Finding the actual industry standard torque specs for #6-48 is hard since it is a specialty screw. The same goes for the #12-32 action screw that Savage uses on their rimfire rifles.

Another thing that you have to remember is how scope rings are machined. The two halves will have a thin shim placed between them prior to final machining to finish size. This allows the rings to clamp the scope when assembled. And since there is a gap between the rings, it is possible to crush a stock if the screws are over torqued. Or you risk breaking the screws off.

Most scope ring screws are #6-48 machine screw. And most manufacturers will recommend between 15 and 22 inch pounds of torque for the cap screws. The average recommendation is for 18 inch pounds. Torquing the rings/mount to the rifle will depend on the size of threads used. #8 or #10 machine screws will have higher torque values than the cap screws. Again go with the manufacturers specs here.

Now the issue with published torque specs becomes more of a problem for action screws holding the actions in stocks that do not have a metal bedding block or metal pillars. I don't know how many times I have had arguments when it comes to torquing Savage rimfire action screws. Savage uses #12-32 screws with a torque value of 15 inch pounds while industry standards for a #12-32 machine screw is around 70 inch pounds, but that is for fastening steel to steel. At that spec, you will crush or break the stock.

There is nothing wrong with using thread locker on scope screw as long as you use the correct type. You want to use a non permanent type of thread locker designed for 1/4" or smaller threads. You will normally have to adjust the torque when you use any type of grease or anti-size compound.

The above information is based on my experiences as a journeyman machinist/tool and die maker. I was also certified as an ASE automotive machinist.
 
I appreciate this information. In the past, I always winged it, never used Loktite, and just guessed how tight I should go. .....until, I broke not one, but two screws during the mounting of a scope on the same rifle....don't ask how!! Anyway, I'm much more cautious now. I remounted the scope that worked loose and used a non-permanent thread locking compound. Haven't been to the range yet, but am optimistic that I've learned my lesson(s).
 
Use torque specs from the ring maker, rail maker, etc.

A tiny bit of blue Loctite does two things, "lubes" the thread, then sets up and makes it harder to come loose.

Don't over do the amount, don't use red unless you never want to take it apart without using heat.
 
Definitely do NOT use red (permanent) loctite on such small machine screws. You will have to heat the screws up to break the bond and there is still a chance of breaking the screws while trying to remove them.

Now if you come across a scope that someone used red loctite on, the best method of heating the screws up is to use a small tipped soldering iron placed on the head of each screw.
 
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12Bravo20 said:
Definitely do NOT use red (permanent) loctite on such small machine screws. You will have to heat the screws up to break the bond and there is still a chance of breaking the screws while trying to remove them.
Click to expand...

Someone put Red Loctite on the magazine tube of a shotgun I bought used. Did not know it was there and I came up with several new cuss words trying to get it off. That stuff does not belong anywhere near firearms. Blue and purple work just fine for 99% of anything firearm related.
 
I have seen all kinds of things messed up because red loctite was used. And it is usually when one person uses it but then another person tries to take something apart not knowing that red loctite was used.
 
I've heard enough red loctite horror stories to permanently scare me away from ever using it. I should be in good shape with my scope mounting experience. I'll have to wait on a range visit for awhile. Here in NE Kansas we've had heat index readings above 120 degrees the last two days and more predicted for all next week. I might hit the range early, say 7:00am before the temps reach triple digits. This summer really sucks.
 
We had a false fall last week. They are predicting temps around 100 for most of the week ( not counting heat index). Needless to say I am going to stay inside as much as possible this week.
 
I use alot of red loctite, and when i cant find my blue it gets used on scope mounts......but i also have a high temp soldering iron and all the taps i need to clean threads......

Sorry to hear your weathers so nasty, its been great here but ive been stuck at home due to covid.
 
Well I guess I've been very lucky
I don't seem to have even a fraction
of the mechanical troubles with my
firearms that so many online post about.
I don't expect to have to remove any
of the optics I have installed on the
firearms I use that have one

I do see that many people online
post about frequently removing
their optics again and again for
whatever reason.
One man got pretty indignant with
me about the subject, and says
that he'll take his scopes off
whenever he wants, and as frequently
as he wants. Which is not untrue,
but he wouldn't give me an answer
about it
I can't see removing a reliable
scope that is zeroed and RTG
but that's just me
 
Ranger99 said:
Well I guess I've been very lucky
I don't seem to have even a fraction
of the mechanical troubles with my
firearms that so many online post about.
I don't expect to have to remove any
of the optics I have installed on the
firearms I use that have one

I do see that many people online
post about frequently removing
their optics again and again for
whatever reason.
One man got pretty indignant with
me about the subject, and says
that he'll take his scopes off
whenever he wants, and as frequently
as he wants. Which is not untrue,
but he wouldn't give me an answer
about it
I can't see removing a reliable
scope that is zeroed and RTG
but that's just me
Click to expand...

I move mine around because i like trying new stuff (my not here pile of gun regs is about 3x the size of my current pile) and it often takes me a while to find a scope and rifle combination i really like.
Im pretty well set on the Meopta my 280AI has on it, the Burris my Ranger wares, and the Leupold my .375 has, but the rest will change again im sure...... actually.375s is gonna come off since i need to redo the cerakote.
 
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I move scopes occasionally on play or hunting rifles, but usually just to upgrade.

On my rifles with picatinny rails I leave the rings on the scope if they come off for some reason. I have three nice scopes with rings in the safe right now.
 
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