Sight Rail Screw Size?

[Deanimator]

As noted elsewhere, the screw holding the Picatinny rail on my Turkish shotgun sheered off yesterday while I was doing function testing.

Does anybody have any idea what size screw that might be? I'm assuming it's metric.

I've got a set of broken screw extractors coming today. Assuming that I don't have too much trouble getting the screw out, I'd like to replace it with a better quality, properly hardened item.

 

[Deanimator]

BTW - I just tried to get the remains of the screw out using a broken screw extractor and the bit barely made a dent in the screw. That indicates to me that rather than overly soft, the screw was overly hard to the point of brittleness.

I'm probably going to have to take it to a gunsmith to have the screw removed and replaced with a proper one.

 

[kudu]

BTW - I just tried to get the remains of the screw out using a broken screw extractor and the bit barely made a dent in the screw. That indicates to me that rather than overly soft, the screw was overly hard to the point of brittleness.

I'm probably going to have to take it to a gunsmith to have the screw removed and replaced with a proper one.

Did you buy the left hand drill bit that you run in reverse? If it even barely grabs it will spin the broken screw out of the threaded hole.

 

[Deanimator]

Did you buy the left hand drill bit that you run in reverse? If it even barely grabs it will spin the broken screw out of the threaded hole.

Yep. That screw's harder than Brandon's head.

 

[Atavar]

Did it shear off flush or inset or is there any sticking out above the receiver?
I have used a tiny dremel diamond ball burr to make a “center punch” divot in a small screw so a drill bit could get a bite to start.
A drop of oil might help after that.

 

[Deanimator]

Did it shear off flush or inset or is there any sticking out above the receiver?
I have used a tiny dremel diamond ball burr to make a “center punch” divot in a small screw so a drill bit could get a bite to start.
A drop of oil might help after that.

I actually have a couple of center punches that I used while building a macrophotography rig. I've already used these to start the drill bit so it won't skip out. Past that point, the drill barely makes an impression.

I've got a full Dremel set, so I might try one of the burrs to see if I can get any deeper.

Thanks.

 

[entropy]

6-48 and 8-32 are the most likely sizes.

 

[Deanimator]

6-48 and 8-32 are the most likely sizes.

Thanks. I'll give those a try, assuming I can get the broken one out with taking it to a gunsmith.

A guy on another forum recommended a different extractor set that he's ordered for a similar problem. If they work out for him, I'll order a set.

 

[Atavar]

I actually have a couple of center punches that I used while building a macrophotography rig. I've already used these to start the drill bit so it won't skip out. Past that point, the drill barely makes an impression.

I've got a full Dremel set, so I might try one of the burrs to see if I can get any deeper.

Thanks.

It will need to be a diamond burr. I don’t think they put those in the starter sets.

 

[Deanimator]

It will need to be a diamond burr. I don’t think they put those in the starter sets.

In that case, I'll wait. I ordered the better set of screw removers a few minutes ago. They're the all-in-one type that sequentially drill and remove, and came highly recommended.

 

[Atavar]

Best luck to you. I would have hated to hear that your dremel skittered and marred the receiver.

 

[Deanimator]

Best luck to you. I would have hated to hear that your dremel skittered and marred the receiver.

Thanks.

If this set doesn't work, I'll be looking for a local gunsmith.

 

[Deanimator]

I just got the second set of screw removers and while it definitely chewed up the screw more than the others, it made no headway in getting it out, probably nicking the edges of the top of the screw hole in the process.

I've asked for recommendations for a local gunsmith, but haven't gotten any responses. I'm thinking that drilling and tapping for a proper Picatinny rail is in order, once I get the gun feeding properly.

 

[Deanimator]

I replaced the OEM rail with a Leapers clamp on rail. It has seven screws holding it in place. I doubt it's going anywhere.