How Much Torque?

[fwafwow]

FWIW, I think the recommended torque on 8-40 screws only jumps to 25 in-lbs.

 

[SDHNTR]

This thread raised some questions for me. I’ve got two rifles with 6-48 screws for which I just got Murphy Precision rails. Should I get the rifle changed to 8-40? Loc-tire or JB weld and max out the torque? Every time I think I’ve got down mounting, or something else, there is more I learn.

What cartridge and what scope?

 

[Dobermann]

This thread raised some questions for me. I’ve got two rifles with 6-48 screws for which I just got Murphy Precision rails. Should I get the rifle changed to 8-40? Loc-tire or JB weld and max out the torque? Every time I think I’ve got down mounting, or something else, there is more I learn.

Wouldn't re-drilling and tapping introduce the possibility for other issues?

Why not just glue it all down and move on?

Or am I missing something ... ?

 

[fwafwow]

What cartridge and what scope?

25-06 and 30-06. As for scopes, that’s another question wasting time in my head - SHV, 3-9, 3-15 and 6x SCs


Post in thread 'NF SHV 3-10x42 *and* SWFA 3-15x42- which one on which rifle?'
https://rokslide.com/forums/threads...-which-one-on-which-rifle.288366/post-2886177

 

[fwafwow]

Wouldn't re-drilling and tapping introduce the possibility for other issues?

Why not just glue it all down and move on?

Or am I missing something ... ?

Nope. That’s probably the smartest way to proceed.

 

[SDHNTR]

Personally, and this is just me, with a 25-06 and that SHV I would not bother with 8-40’s. With the 30-06 and the SWFA I would want the bigger screws. And I would bed both, but I’m not a permanent bond guy. If you’re gonna bond permanently, 6-48’s are fine for both.

 

[fwafwow]

Personally, and this is just me, with a 25-06 and that SHV I would not bother with 8-40’s. With the 30-06 and the SWFA I would want the bigger screws. And I would bed both, but I’m not a permanent bond guy. If you’re gonna bond permanently, 6-48’s are fine for both.

Thanks. Permanent is JB weld?

 

[SDHNTR]

That’ll do!

Thanks. Permanent is JB weld

 

[Drenalin]

From my research, if you put a bond breaker on top of the action, like shoe polish, you can accomplish the bedding without the semi permanent bond. JB Weld or similar would work in either case.

 

[Kimber7man]

Nightforce Torque Specifications
• Base attachment screws - 25 inch pounds
• Ring top screws - 25 inch pounds
• Ring crossbolt nut - 68 inch pounds

 

[Dobermann]

Nightforce Torque Specifications
• Base attachment screws - 25 inch pounds
• Ring top screws - 25 inch pounds
• Ring crossbolt nut - 68 inch pounds

Some NF mounts have had different quoted specs for the crossbolts at different times ...

 

[Drenalin]

Got it all together. Pretty excited to see how this goes.

 

[Woodrow F Call]

I've done what form recommended..... didn't use a torque wrench, degreased, tightened till it felt like it was about to snap..... seems to work.

I understand not everyone has turned enough wrenches to have that feel and torque wrenches/values help here.

 

[ResearchinStuff]

If you're using the wrench key you probably can feel it approaching max tensile strength. (will be below 65 in-lbs for a 6-48). If you're using a torque wrench set at 65 I think you're just going to break a 6-48, there's not enough feedback to your fingers on what's happening to the bolt. Ideally, you'll torque a fastener to just about the top of its linear elastic range, maximizing clamping force without permanently elongating the screw.

Even if the 6-48 doesn't break, at a certain point you go past elastic deformation and towards ultimate yield strength, so the screw will not be reusable. Exceed the ultimate yield strength and the thing will deform plastically, thus clamping force is actually decreased even though it's "tighter", torque a little more and it breaks.

This is all easy to see on a stress-strain curve, and it's also why dink screws shouldn't be used. It's pretty easy to tap out a 6-48 to a 8-40, and while the torque limits are similar, the larger cross section enables a good bit more tensile stress (ie clamping power) for the same elongation.

Stress–strain curve - Wikipedia

en.m.wikipedia.org

Regarding loctite, leupold screws normally have the blue loctite on them from the factory.

 

[Pickettpuncher]

I've done what form recommended..... didn't use a torque wrench, degreased, tightened till it felt like it was about to snap..... seems to work.

I understand not everyone has turned enough wrenches to have that feel and torque wrenches/values help here.

That’s what the last idiot done and now the holes are getting redrilled and tapped. Tight is tight and too tight is loose.

 

[Woodrow F Call]

That’s what the last idiot done and now the holes are getting redrilled and tapped. Tight is tight and too tight is loose.

You did read my qualifying statement right?

Torque values can be a useful tool.

 

[Reed104R]

This thread reminds me of a time years ago at the National Gun Day show in Louisville. Several of us went to a Japanese restaurant on Saturday night. While waiting, we got into an argument about the capabilities of the various types of Loctite (we had the colors confused). As it turns out, a guy sitting across the table worked for Loctite. He straightened us all out pretty quick. Perhaps he just wanted eat his meal in peace rather than listen to a bunch of rednecks argue about Loctite!!!! Just like reading this thread, it was a learning experience.

 

[fwafwow]

Wouldn't re-drilling and tapping introduce the possibility for other issues?

Why not just glue it all down and move on?

Or am I missing something ... ?

Sorry to resurrect this thread with more ignorant questions.

I'm not going to re-drill and tap, so I'm sticking with my new rails and the #6-48 screws, and I'm hoping to finish this project and "permanently" attach the rail to reduce movement of this component.

Question - what type of JB Weld is strong enough to work for these purposes, especially in the off-chance I change my mind down the road? It looks like the original can withstand 5020 PSI and 550 degrees and I expect would be the hardest to remove. It looks like KwikWeld withstands 3127 PSI and 300 degrees (so I'm guessing easier to remove down the road) and sets up faster. Would that be sufficient?

 

[BrentH]

Sorry to resurrect this thread with more ignorant questions.

I'm not going to re-drill and tap, so I'm sticking with my new rails and the #6-48 screws, and I'm hoping to finish this project and "permanently" attach the rail to reduce movement of this component.

Question - what type of JB Weld is strong enough to work for these purposes, especially in the off-chance I change my mind down the road? It looks like the original can withstand 5020 PSI and 550 degrees and I expect would be the hardest to remove. It looks like KwikWeld withstands 3127 PSI and 300 degrees (so I'm guessing easier to remove down the road) and sets up faster. Would that be sufficient?

I actually came back here to ask a similar, but opposite, question about JB Weld.

A while back, I put a scope rail on with the strongest JB weld. Used release agent on the screws, but when re-torquing the screws I stripped one and couldn’t get it out. That left me with trying to figure out how the hell I was gonna get the rail off. Well, two hours in my freezer at -10* F, a quick tap from a rubber mallet, and the JB welded rail popped right off.

Now, I’ve never hunted where it’s -10 degrees, but it left me wondering what the cold threshold actually is for JB weld? Is there something better to use that works across a broader range of temps?

 

[Pickettpuncher]

Sorry to resurrect this thread with more ignorant questions.

I'm not going to re-drill and tap, so I'm sticking with my new rails and the #6-48 screws, and I'm hoping to finish this project and "permanently" attach the rail to reduce movement of this component.

Question - what type of JB Weld is strong enough to work for these purposes, especially in the off-chance I change my mind down the road? It looks like the original can withstand 5020 PSI and 550 degrees and I expect would be the hardest to remove. It looks like KwikWeld withstands 3127 PSI and 300 degrees (so I'm guessing easier to remove down the road) and sets up faster. Would that be sufficient?

If I was to do what you’re saying, I’d use regular jb weld with no release agent.