Home Forums Hunting & Shooting Ask The Gunwriters Inch Pound Torque Wrench

I have one also

Generally, whatever the mount manufacturer recommends, which is generally around 17-20 inch pounds--though scope manufacturers also often suggest settings.

But it varies with the thickness of the scope tube. Nightforce generally recommends 25 inch-pounds, because their tubes are thicker than typical lighter-weight hunting scopes, and NF scopes are also heavier as well, which often requires tighter rings to keep them in place during recoil (which if course also depends on the cartridge and rifle weight).
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Years ago I was told by a VP at Nightforce that with theor rings 15 inch pounds. I went 14 and have never had a scope move
I haven't asked their recommendation since so I'm not up to date

MATCO tool truck have them, probably as would Snapon, or Mack. Mine is a very old Snapon it will out last me. Plus there are many different types.

Actually I have 2 inch pound torque wrenchs. The other is a Mack I believe. The difference is the Mack has a bar that bends with a pointer on it. The Snapon

is the more expensive click type. I used the Mack type to set pinion bearing drag as you can see when you are getting close to the spec. The Snapon won,t tell you how

close it is until it clicks.

All of mine, annually

You may pick your wrench.

Received both the Brownell’s Seekonk and the German Wiha . For my needs the Wiha is about perfect .

A good inch pound screw driver is a must.

Solid choice.

I didn't use a torque wrench for years, never a problem that I know of but I decided about two years ago to give it a try and I would not mount rings/bases/scope without one if I could avoid it. Getting the screws all to spec not only eliminates the guessing game but also results in uniform consistency for all 8 scope ring screws and I believe that's got to be a benefit to more consistency and longevity. I do agree that overtightening is more of a problem for most people and the torque wrench helps avoid that too. I went with the Wheeler Fat Wrench, not the most expensive but I'm satisfied with it.

All y'all torque lovers:

What corrections do you use for lubrication?

What corrections do you use for friction?

Since torque is not a direct indicator of tension, what calc do you use to ensure the correct tension on your fasteners?

Just curious...

I'm mounting a scope, not working on Air Force 1.

Then why use a torque wrench that won't yield accurate tension, vs simply using a T wrench designed to yield the accurate tension for a a given T tension?

A torque wrench, used in a less than perfect manner! beats the ass off
a screwdriver twisted untill your teeth grit. Twice.

(The old fashioned "Farmer Tight" method most traditionally use.)


I know using a torque wrench usually results in a big surprise in how
little effort it takes to properly tighten most fasteners.

Often am uncomfortable with how tight I haven't made lug nuts.
100ft/lbs sure is a long way from pulling on the bar till I grunt.

A torx wrench of the proper factor snugged and then pulled to 90* will be more consistent 70 times than a piece of [bleep] torque wrench.

I took my BS in Structural Engineering in 1982. At that time the accepted design criteria was ASD - Allowable Stess Design.

After several years working in Petro Chem Offshore the US finally caught up with the rest of the world that LFRD Load Factor and Resistance Design was the more accurate specification, and that is what is used now in all US design. I did my Masters on the transition.

Simply put, and argue all you want, but please supply references: For the last 25ish years, I've not worked on ONE project on 5 continents where TORQUE is acceptable as an indicator for tension in critical service. Turn of the Nut, which is equivalent to using say a T25 and pulling it to 90* is ALLOWED on non-critical systyems. Hydro-Tensioning, ie measuring the stretch on the fastener is spec'd for critical systems....and TORQUE NEVER meets the requirement...

What happened to Farmer Tight being good to go ?

😬🦫

PS

I use a torque wrench for mounting or seating screws on a rifle.

Journeyman,

Apparently you missed this post I made on this thread back on 7/20:

The primary reason torque amounts started being suggested for scope mounting was NOT the strength of the screws, but the strength of scope tubes. A LOT of people (including some so-called professionals) were over-tightening ring-screws to the point where scopes started to malfunction. This is especially true of variables, since they have an "inner tube" (the erector tube, which in variables changes magnification) that can be affected by too much ring tightening. But over-tightening can also affect adjustments, and in some scopes it doesn't have to be much to affect them.

Not only didn't miss it...but disputed it. If a t15 or t25 snugged and pulled to 90* affects your scope...dump that POS...

Marty Bordson, Glen Seekins, Jered Joplin and I have had this discussion years ago...

Here's what Marty says now...
Badger Installation


Again, John - my point is that a POS wrench off by 6% +...+ no correction for the friction factor on the fasteners...+ no correction for any lubricant or locker....= the problem you describe MUCH MORE than using the long end of a torx wrench as tight as one can twist it..

Journeyman,

Looks like Marty still gives torque values in in/lbs as does Nightforce and Spuhr uses both in/lbs and Newton/meters.

rather than delving into engineering theory, what tool and method do you recommend for mounting scopes?

Looking for specific info to use.

Thanks.

Not the expert that some of you evidently are. But on a project I was on, the contractors had to buy new torque wrenches and had to have them calibrated every six months. The torque wrench that they were using was a very common torque wrench (I owned two of them at the time) and according to the mechanical engineering group could be off by 50% easily.
Therefore, I’d like to see the specification by the scope manufacturer including plus/minus % and pick the appropriate wrench.
If the scope manufacturer wants 25 inch pounds plus or minus 1 inch pound then that would narrow the choice, I’d guess.
I’m pretty sure my choices were often made by the $’s I had at the time and not to what was the best tool for the job.

Jeff,

You said "rather than delve into engineering theory", so I offer this:

There are two companies that own the thread locker market, Henkel (LOCTITE) and Permatex. I have friends at both. One of my friends worked on this layman's manual:

LOCTITE Threadlocker Manual

Go to Section 6 "Threaded Assemblies" and read it through. You'll note at Section 6.2:

Method 3
Measure torque

This is the simplest and most widely implemented method used in engineering.
It is also the least accurate. The variables involved in using this method can result
in errors of ± 25%. The margin of error can be magnified by coefficients of friction, lubricants, burrs on bearing surfaces, flexibility of the structure and operator
error. Therefore, when torque is used to control clamp load, testing is recom-
mended to determine either the coefficients of bearing and thread friction
or the k-factor of the assembly configuration.

Since you said you don't want to get into engineering theory let's skip the k-factor discussions and cut to the chase...

There are 3 influencing factors that affect proper tightening: Bolt Tension, Thread Friction, and Head Friction.

What I suggest, is:

Dump all fasteners in acetone and clean them to bare metal.
Use a cotton swab soaked in acetone to clean the threaded assemblies.
Apply Loctite 248 STICK Loctite Stick then use the proper torx wrench, ie 15/25/whatever and snug , then twist to 90 *(another of your questions - * = degrees)

This will ensure you get the minimum clamping force to avoid slippage.

Now, to sound like a hypocrite, I then use a Wiha torque wrench calibrated to a test block to see where it clicks at the value stated by the ring or scope manufacturer. Almost always it clicks before applying anymore tension...