Stripped scope ring hole - fixes?

H Wally

H Wally

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Came back from the range today with some issues with a scoped hunting rifle of mine.

One of the threaded holes in the rings has stripped out (no fault of mine I may add, I got the gun, checked it over and discovered the issue).

The screw itself is fine - maybe slightly worn, but nothing serious. The hole itself seems to be stripped out, as the other screws spin in it as well, and the screw taken from it will thread perfectly in other holes.


SO.


How do I solve this? The threads are very fine and the screw diameter is also quite small. It was suggested I put some JB weld in the hole and then oil up the screw and thread it in, let it set and I'll have a make - do threading. This sounds pretty risky to me, but I don't see much of an alternative, as it's a quite small hole, fine threading, and I don't think I could find a helicoil of the right dimensions to fill the hole.

What should it cost a gunsmith to repair?
 
Got any measuring gear? Like a CTire digital caliper?

Measure the diameter and figure out what size you have. Look at the Brownell's site, and check out the availability of oversize screws.

Chances are, any reasonably equipped smith will have the screws and correct taps in hand.

This is not a new problem.

Very best fix, is to have the screw replaces with a slightly larger one, after the hole has been either determined to be stripped (at which time, it needs to be tapped out again) or the screw needs to be replaced with the correct one (in the off chance that the hole is actually intact and the screw is the wrong size).

Yer on the Island? Pretty sure Guntech is in Brentwood Bay area. If he does not chime in, maybe shoot a PM in his direction.

Cheers
Trev
 
If the screws are 6-48, Brownells sells a slightly oversized tap and screws to address this problem. Works very well. Or, you could open everything up for 8-40.
 
It's a yugoslavian Zrack mount. The quick release version:

http://www.zrakus.com/zrak-m98-scope-mount-rin98.html


Info on the screws here:
http://www.canadiangunnutz.com/forum/showthread.php?t=485788&highlight=zrack

I have never tried to work on scope mounts before, which is why I'm asking. However, I think I'll be capable of doing the work once I understand the right course of action.
 
If it's just the rings and not the base(s), it'll probably be cheaper to replace the rings rather than buy a tap, etc.?
 
Get it to a gunsmith, or buy the tool to drill and tap 8-40. The Brownell's 6-48 stripped tap works well if the hole is not too big. Probably cheaper to have a gunsmith do it, unless you have a use for the tap(s) again later.

You need a regular tap and if the hole is blind you need a bottoming tap as well.
 
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Or you can save the coin and buy a Mastercraft tap for 8-32 tap the holes, grind the lead off the end of the tap then bottom it out. And install capcrews from Canadian Tire too. Of cource if its a Yugoslavian made scope mount the screws are probably metric which explains the fine thread.
Correct me if I'm wrong but a coarser thread pitch will hold up better in softer material like aluminum, since there is more material between each thread, won't it?
 
ciphery said:
Correct me if I'm wrong but a coarser thread pitch will hold up better in softer material like aluminum, since there is more material between each thread, won't it?
Click to expand...

No. Generally speaking finer threads will take more torque without stripping than coarser threads will. That's the reason that scope mounts and bases are generally 6-48 or 8-40 instead of the more common coarser threads in these screw sizes.
 
trevj said:
If ya missed it HWally, I posted an answer that I hope is of use, here http://www.canadiangunnutz.com/forum/showthread.php?t=485788&highlight=zrack

Good luck!

Cheers
Trev
Click to expand...

Thanks for the link and response in the other thread! I'm in an odd place where I've messed around with helicoils, and tap and die sets, but never actually been taught, so there are huge gaps in my knowledge on the subject!

That's quite helpful, I think I'll try sourcing materials and see what happens.
 
J.B. Weld has been used to fix stripped theads in cylinder Blocks (usually on manifolds) and the repairs last years
 
if you re tap it the best way to do so and make sure its a true tap is mount the base in a drill press vise chuck the tap in the drill press (unpluged) lower the head till tap contacts keep pressuer on the lowering handle and turn the chuck by hand (if your rifle is true to the drill head you will get a machine quality taping ) thats how a smith will do it
 
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