Torque on frame mount?

[Bostenelli]

I’m guessing 18 in/lb for the frame optic screws on a 2011 major open gun?

 

couldn’t find on google or this forums oddly enough. Maybe I didn’t use the right combo of key words??

[Rich406]

On 11/17/2023 at 6:28 PM, Bostenelli said:

I’m guessing 18 in/lb for the frame optic screws on a 2011 major open gun?

 

couldn’t find on google or this forums oddly enough. Maybe I didn’t use the right combo of key words??

I generally torque the large optic screws to 25 in/lb and the smaller plate screws to 15 in/lb. 
 

when removing if I get any excessive resistance at all. I go right to using heat and then they come right out with no issues. Some screw, especially the ones trijicon uses are super easy to strip out and a bitch to remove once you do. 

[Braxton1]

If we're talking "screws for frame-mounted optics", we're probably using 5-40 screws.  The recommended torque specs for those ranges from 7.7 to 8.1 INCH-POUNDS.

 

That is light-as-heck, so good thread sealant is critical.

[CHA-LEE]

For the Frame Mount to Frame screws, they are usually 5-40 size screws which are not very big, but I have ALWAYS tightened them to almost "Twizzler" a normal "L" shaped Allen Wrench level of tightness. That and use Red Lock Tight on the screws. The standard "inch-Pounds" torque spec's for those tiny screws is absolutely not enough to prevent them from working loose.

[shred]

You'll see 5-40 and 6-40 (and 6-32 and 6-48 and M-whatever... ) on frame mounts.  Since you extremely rarely want those to move, do what Cha-Lee suggests and crank 'em down with plenty of loctite.  Dawson used to suggest #620 green sleeve retainer for scope mount screws.  Those aren't coming out without heat and much hassle so maybe red is better if you ever plan to change mounts.

 

 

[Rich406]

1 hour ago, Braxton1 said:

If we're talking "screws for frame-mounted optics", we're probably using 5-40 screws.  The recommended torque specs for those ranges from 7.7 to 8.1 INCH-POUNDS.

 

That is light-as-heck, so good thread sealant is critical.

Torque that light will never hold up on a slide ride optic.

[rishii]

big plus one to the above

Also I’ve learned never to reuse the screws, if you remove them, toss them and fit up new ones

If you reuse the screws there a good chance the next time you remove them one of them will round, then it’s screw extractor time on a tiny screw

[Bostenelli]

I couldn’t find much info so asked my shooting buddies

 

18in/lb seemed pretty consistent 

 

i hit all the threads with break cleaner then used blue loctite and cleaned out the threads. 

 

also found a link to a website for trox plus heads versus those tiny hex heads I absolutely always strip. 

I’ll see how it holds up

 

[JRM83]

I don't understand why all the parts manufacturers and builders are using tiny hex screws instead of torx. I replace the hex screws with torx wherever possible. 

[George16]

1 hour ago, JRM83 said:

I don't understand why all the parts manufacturers and builders are using tiny hex screws instead of torx. I replace the hex screws with torx wherever possible. 

To cut costs. Hex screws are cheaper than torx screws. Less overhead means bigger profits .

[shred]

I use Torx-Plus from McMaster if they have them.  Get a few of the bits while you're ordering a box of 50 screws.  

 

The easiest way I found to shorten them is find a scrap of 1/8" steel flat bar and drill and tap it (assuming STI "wide" dustcover.. adjust thickness to match).   Drill and tap for your screw(s).  Bolt your mount to the flat using new screw.   Hold the other end to a belt sander (don't overheat it) until said screw is ground flush.  Unscrew, install in gun.

 

[Bostenelli]

Yup that’s the place I think I found the site

 

I used a dremel and they are pretty flush 

[Maximis228]

Always use red thread lock on frame mounts. Blue will fail overtime. 

Edited November 22, 2023 by Maximis228

[CHA-LEE]

5 hours ago, Bostenelli said:

I couldn’t find much info so asked my shooting buddies

 

18in/lb seemed pretty consistent 

 

i hit all the threads with break cleaner then used blue loctite and cleaned out the threads. 

 

also found a link to a website for trox plus heads versus those tiny hex heads I absolutely always strip. 

I’ll see how it holds up

 

 

Let us know how many rounds until the screws start to back out because they will when only torqued to 18in/lb.

[zdali]

4 hours ago, Maximis228 said:

Always use red thread lock on frame mounts. Blue will fail overtime. 

222 purple for fine thread

[Rich406]

13 minutes ago, zdali said:

222 purple for fine thread

Won’t hold up under hard use. 
 

There are lots of preferred specs for these small fasteners, but the amount of force they take in this application is way beyond what would be considered normal use. 
 

You can start with some of the advice in this thread and torque to 8 in/lb and purple loctite.  From personal experience this won’t work. 
 

Or.  You can over torque it and use red loctite and reduce or eliminate problems. You just need to be aware and careful if you need to remove the fastener.  

[lroy]

I swap between open and LO with my gun so I take it off pretty regularly. I just blue loctite and 25lbs. I've never had an issue.