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Normal Topic unertl rear scope mount problem (Read 2519 times)
dick_eesley
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unertl rear scope mount problem
Sep 5th, 2010 at 11:47am
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Had to leave fall ASSRA matches due to a faulty posi rear scope mount which would'nt tighten  experts there surmised stripped threads    can I dare tap the mount with 6-40 tap??   also 6-40 screw in bad shape and needs replacement  seems the 6-40 screws moves freely in the larger od threaded piece  is this normal   been using the scope mounts for thirty years    any solutions   dick eesley
dick eesley@yahoo.com
  
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SteveC
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Re: unertl rear scope mount problem
Reply #1 - Sep 6th, 2010 at 12:12pm
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Sounds like a job for a Heli-Coil.It looks like a coil spring with a diamond shaped cross-section. You drill out the hole to the pitch diameter of the original screw and tap with an oversize tap. Then screw in the Heli-coil and break off the insertion tab. Stronger than the original. You should be able to find them at auto parts or industrial supply stores. Hope this helps.
                                           Steve
  
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40_Rod
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Re: unertl rear scope mount problem
Reply #2 - Sep 7th, 2010 at 8:08am
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The problem is getting to it. the stripped thread is in the rear mount. The hole could be drilled from the front but then getting the heli coil in would be imposible. The best way to fix it would be to make up a new screw on a larger screw.

40 Rod
  
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bulldog1935
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Re: unertl rear scope mount problem
Reply #3 - Sep 7th, 2010 at 3:58pm
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a helicoil requires an even larger drilled and tapped hole for a smaller screw thread.  Just going up one size in screw with a new bottom-tapped thread makes the most sense - it's the smallest hole to solve your problem.
  
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