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Czechmate CMore mount screws loosening, help

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I can't keep two of the three screws that attach the CMore mount to the frame tight. For the first year and a half, a dab of 242 blue would keep everything happily in place. Now the two outside screws loosen after one mag, and that's with 271 red trying to hold them in place. Everything gets fully degreased, twice, with brake cleaner, and the red is allowed to set up for 36 hours plus before firing. Considering the rear hole is blind, I don't think oil contamination from the slide rails is at fault. Outside of TIG welding the mount to the frame, any one have a suggestion?

 

Thanks in advance.

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If you have a set of M4 x .7 tap and die, use the tap to clean the threads on the holes and the die to chase the threads on the screws. Degrease them, use blue loctite to reinstall screws and let it set for 24 hours.

 

I have done this for screws that keep on loosening up. Sometimes, even brake cleaner cannot thoroughly  remove all the residue between the threads. 

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You're using red loctite and it's still coming loose?

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Clean the holes as described. Use shellite to degrease and use a fresh bottle of red loctite


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No cracks visible, plus last weekend was a fresh chapstick tube of red loctite. I'll look for shellite and a tap and die.

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No cracks visible, plus last weekend was a fresh chapstick tube of red loctite. I'll look for shellite and a tap and die.
Would be great to hear the update on this after you're done.

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11 hours ago, Matt1 said:

Clean the holes as described. Use shellite to degrease and use a fresh bottle of red loctite


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What is Shellite might be a auto spell check screw up lol

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What is Shellite might be a auto spell check screw up lol


285a799a7aca07c26cbb9025ecc65a5c.jpg


Wax & Grease remover from an auto store would work as well.


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Thanks learn something every day never heard of it.

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See the post by GregT, new torx screws. You might need a new mount if the holes in the mount are flogged out. 

 

 

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Use a Loctite primer for anaerobic threadlockers. 

83D64C50-0DEE-489A-9C3F-46A2790E9BE9.jpeg

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I can't keep two of the three screws that attach the CMore mount to the frame tight...

 

Do you have a thumb rest attached over the mount?

 

Those screws can, over time, allow the mount to move and lose zero.

 

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Had same problem with my Czechmate sight mount.  Had to chase the threads and then clean and re-clean them multiple times (including the threads on the screws) with brake cleaner, and then the Loctite cleaner.  Used RED Loctite and have not had an issue since.  The least little bit of oil / grease in the threads and the Loctite will not cure properly.  I use the liquid and not the stuff that is in the "chapstick" tube.  The other option to the Red is Green 632 Loctite.  I have used that in the past to mount compensators on other guns, but will warn you that you will definitely need to heat up the screws if you should ever need to remove them.

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It’s not the tightening its stretched screws. Replace them.


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Update: I thoroughly cleaned the screws and holes with brake cleaner and acetone, and on the advice of an old  machinist used Loctite 7649 primer and 290 green. Finally made it to the range today and dumped 200 rounds as fast as I could. Everything is holding just fine. The machinist said that Loctite 240 / 260 / 270 series were all designed with 1/4< screws and bolts in mind, whereas 290 was designed for screws as small as #2's. I dunno, but so far so good. I also had a suggestion for Vibra Tite from another old school shooter who swears by the stuff. https://www.vibra-tite.com/industries/firearms/  I might try that in the future for grins and giggles. Oh, and new screws came in from CZ USA, just in case.

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