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Screw size for optic mount?


TeedOff

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You guys have been very helpful on my open journey...so here's another what is probably a stupid question. I'm trying to mount a thumb rest on my new ck Arms open gun, but the screws supplied are too short. Of course the local hardware store doesn't have anything this small. So what is the screw size? Not worried about the length...will cut to fit. What is the typical diameter and thread pitch?

 

 

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Working on the 2011s can be as addicting as shooting them.  Have fun!


I still have a lot to learn. Appreciate all the guidance I've gotten here.


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I bought 5-40 x 1/2" ones and they were too short when I mounted my thumbrest. (cheely offset mount & RHT loud pedal). I order a 50 pack of 7/8" and just cut them to length. that way I know I will always have long enough screws to put whatever combination of mount and thumbrest on my guns.

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Funny, I just got a DAA thumbrest.  The screws supplied were too big to fit into the stock CK hole.  I was just going to ask and my question was already answered.  I'm going to order some longer ones and will cut them down to size as well.

 

Thanks for answering the question before I even ask!

Edited by vtecpaoche
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9 hours ago, scooterj said:

Avoid stainless. They are soft and will twist off. 

 

Amen to that. Hardened mild steel in the black iron oxide style finish is what you need. The junk stainless ones will strip heads easily....

 

the daa rest may have come with metric screws which are what is used on tanfoglios and aimpoint setups. 

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5-40 on CK's and 6-40's often on other guns. For the 5-40's I upgrade everything to torx plus to get away from stripping hex keys and sockets. 

 

I've yet to find a good source for torx plus 6-40 flat heads. If anyone knows somewhere please pass it on. 

 

 

Edited by theWacoKid
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5-40 on CK's and 6-40's often on other guns. For the 5-40's I upgrade everything to torx plus to get away from stripping hex keys and sockets. 
 
I've yet to find a good source for torx plus 6-40 flat heads. If anyone knows somewhere please pass it on. 
 
 


Do you have a link or source for Torx screws in 5-40? All I'm finding are hex and I've already experienced stripping the head. Grrr!


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4 hours ago, TeedOff said:

Do you have a link or source for Torx screws in 5-40? All I'm finding are hex and I've already experienced stripping the head. Grrr!

 

 

McMaster is the place to get torx plus 5-40's and the torx plus wrenches.  The 6-40's unfortunately aren't available.

 

 

Edited by theWacoKid
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2 hours ago, Sandbagger123 said:

 seeing that 6-32 is a lot more common, would there be any issue in using it instead of 6-40? 

 

You just get a little more thread engagement in the thin amount of frame available. But the guns tend to already be threaded 5-40 or 6-40 to start with so you're stuck in that box. 

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6 hours ago, Sandbagger123 said:

 seeing that 6-32 is a lot more common, would there be any issue in using it instead of 6-40? 

 

6-32 will give you less threads to engage. The second number is TPI - threads per inch. 

 

My infinity had 5-40s too. When one snapped I drilled the holes out and re-tapped them to metric 4mm fine thread. More threads and bigger/stronger screws with larger flats on the heads. So much nicer. I have nfi why everyone uses such pissy little screws. :(

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