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  #1  
Old 12-24-2015, 05:51 PM
s11033 s11033 is offline
 
Join Date: Oct 2013
Location: Boston, MA
Posts: 192
Default M1D Scope Mount Lock Screw Help

Hey,

I recently purchased a nice M84 and GI scope mount for my CMP M1D, but when I went to mount the scope, the lock screw knob only turned about 1.5 turns before it stopped dead. I backed it out and took a closer look. It appears that the shaft of the screw is somehow slightly bent. My friend that is a gunsmith agreed when I showed it to him.

I have seen a couple forum threads about repairing mounts with stripped screws, but am not quite sure if any of these methods can solve the problem without ruining the value of the original GI mount. Any ideas? Alternatively, is there anyone that repairs GI scope mounts?

Thanks for the help guys,

Steve
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  #2  
Old 12-25-2015, 05:38 AM
lapriester lapriester is offline
 
Join Date: Oct 2009
Location: Cobb, N California
Posts: 16,364
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There is nothing you can do to repair the mount without ruining it's value and possibly nothing you can legitimately do to repair it at all. But, unfortunately...or fortunately...in it's current state it has little value anyway and is definitely not capable of being used as it is.

Private seller? If so I would be having a serious talk with him about a refund of the value of the mount since what was sold to you is useless. The shaft of the screw is machine swaged to the knob meaning you'll have a seriously difficult time separating the two without destroying one or both parts. Destroying the screw doesn't matter but, destroying or damaging the knob and what's under it is. Then, finding a replacement screw that will properly work right may be troublesome and the knob will no doubt have to be welded to the screw. All that's probably possible if you want to save and use the mount for a shooter. But, any value it once had will be destroyed in the process. Finding someone who can do it all properly will be your greatest accomplishment in the process.

Is it possible you could put a nut on the screw, figure out the direction it needs to be bent to straighten it and give it a good whack. Is the knob crooked on the screw and causing the actual problem? It's hard to imagine the screw would get bent since it's so short unless it was run over by a tank. I would think it's more likely the knob is crooked on the shaft. Maybe the knob could be heated enough to be able to bend it back straight on the screw. You may need to be inventive here with a solution. If it's the knob being crooked, maybe you could screw the mount on the block as far as it will go and use a wide thin tapered chisel between the low side of the knob and the mount, tapped by a hammer to straighten it a little bit at a time until it will continue to tighten. If you end up trying that be very careful you don't bung up the washer under the knob in the process. It's a critical part of the assembly you don't want to break or damage.

Good luck.

Last edited by lapriester; 12-25-2015 at 05:55 AM.
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  #3  
Old 12-29-2015, 01:49 AM
s11033 s11033 is offline
 
Join Date: Oct 2013
Location: Boston, MA
Posts: 192
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Thank you very much for your very informative reply. Sorry I have been off the grid for a couple days.

The knob is definitely bent because when I push the knob against the casting body and turn it, I hear and feel the clicking of the slots in the rear of the knob against the stop on the casting body for 3/4 of the turn and hear nothing for the remaining 1/4. I am unsure whether or not the screw itself is bent. I have read somewhere that the threads are 12-32 and none of my local hardware stores have those threads. Any idea where I can get a nut threaded in 12-32 to determine whether the screw is bent?

I have found taps for that thread but have never threaded anything before myself.

http://www.midwayusa.com/product/911...p-12-32-thread

Thanks again for the information.

Best,

Steve
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