Stripped Strain Screw Hole - Model 10

[kev74]

I bought myself a Model 10-4 a couple of months ago and finally dug into it to give it a good cleaning.

Upon reassembly, the strain screw wouldn't grip in the hole in the frame. The hole is stripped out. I'm guessing the screw had been threadlocked in place, but I didn't notice anything funny when I took it apart.

I tried making a new strain screw, toward the tighter end of spec, but that one slipped too.

Now I'm wondering what my best course of action will be for repair. I could weld or braze up the hole and re-drill and tap it. I was also thinking about making a tiny thread insert, but don't know if I'll have enough meat in there for that. Last resort (or maybe best fix???) is to drill it out and retap for 10-32.

Any thoughts, tips or ideas are appreciated.

 

[DWalt]

I would personally make a screw with a little larger diameter and enlarge and tap the hole in the frame.

 

[savageman101]

IMHO..... I wouldn't do Any of those things. Either take it to an expert or "Glue" it back in and sell it. "Being facetious"

 

[BC38]

I'd tap it for a slightly larger screw. Something just a few thousandths larger in diameter. Maybe a metric size even. Though I think I would go for something with a finer thread than a 10-32.

 

[BC38]

IMHO..... I wouldn't do Any of those things. Either take it to an expert or "Glue" it back in and sell it.

Really? Sell it with a known defect to the next sucker in line, huh?
I wouldn't bother trying to sell anything on this site after a comment like that.

 

[savageman101]

I'd tap it for a slightly larger screw. Something just a few thousandths larger in diameter. Maybe a metric size even. Though I think I would go for something with a finer thread than a 10-32.

How would you do the counter bore of the new hole?

 

[scattershot]

How would you do the counter bore of the new hole?

Carefully.

 

[savageman101]

Really? Sell it with a known defect to the next sucker in line, huh?
I wouldn't bother trying to sell anything on this site after a comment like that.

I was being "Facetious" (treating serious issues with deliberately inappropriate Humor)

 

[BC38]

How would you do the counter bore of the new hole?

Counterbore to allow the new screw head to be flush with the front strap? What's hard about that? Just bore the counterbore for the head first, then bore & tap the threads for the screw.
Not hard to do with a drill press.

 

[kev74]

I've got a pretty well equipped shop here.

I'm reluctant to go to 10-32 because it it a relatively big jump in size. The diameter of 10-32 is almost as big as the counterbore in the frame.

 

[BC38]

I was being "Facetious" (treating serious issues with deliberately inappropriate Humor)

Then you need to separate your serious comments from your facetious comments. Putting them in the same sentence makes them both sound equally serious.
An emoji for the facetious comment might be a good idea too. Otherwise people are going to take your comments at face value.

 

[savageman101]

"Otherwise people are going to take your comments at face value"

Probably just you

 

[chief38]

If it were mine, I would re-tap the hole for the next size standard SAE thread. That should be a #10 x 32tpi screw that was cut and polished to the proper length. The width of the head might have to be reduced to counter sink and fit as the original 8x32 screw did. This is not a hard job for someone mechanically inclined and familiar with drilling and tapping holes. I believe the correct size number drill for a 10x32 tap is a #21 (.1590").

Use plenty of lubricant, a good quality Tap and don't forget to back out Tap a half turn to clear out chips often. Keep it as straight as possible and you should be good. If you have not tapped holes often, seek out someone more familiar doing so. Removing a hardened and broken Tap is not fun.

There are other methods that would work as well, but I personally would not lean towards welding or plugging a Revolver. Permanently lock-tighting in a screw is not a good idea either IMO.

 

[Mike0251]

Just a thought for you:
I believe the thread size on the strain screw is 8-32? = .164" Major diameter

The smallest dia modification that you "could make" would be an M5 metric thread. That requires a #19 drill (.166") and then tap to M5 (.196" major dia)

Yes it may be a metric thread but you have removed the smallest amount of material to do this. Just a thought. Measure what you have, run the numbers and give it some thought. All other screw dims remain the same.

Sounds like you have the ability to make your own screw? If so this may be your way forward.

 

[sbrmike]

If this was mine, I would get a new standard size Strain screw and make a nut if I couldn't find an appropriate size nut. Assemble it with the grips off, use loctite and it will work fine.

Welding up will affect finish, there is not much room to bush when you figure in the counter sinks. The nut will work and not be visible externally.

 

[Protocall_Design]

I would just run a 10-32 tap and screw in a 10-32 x 1/2" long headless setscrew with some blue or purple Loctite. Don't need a counterbore for the head (no head) and you can adjust it with an allen wrench any time you want to. Job done.

Edit to add - You want a 1/2" long setscrew for a square butt frame, a 3/8" long for a round butt frame.

 

[chief38]

Just a thought for you:
I believe the thread size on the strain screw is 8-32? = .164" Major diameter

The smallest dia modification that you "could make" would be an M5 metric thread. That requires a #19 drill (.166") and then tap to M5 (.196" major dia)

Yes it may be a metric thread but you have removed the smallest amount of material to do this. Just a thought. Measure what you have, run the numbers and give it some thought. All other screw dims remain the same.

Sounds like you have the ability to make your own screw? If so this may be your way forward.

The original screw was an 8x32 - yes you are correct. The next size SAE screw is 10x32. Just my own preference, but I'd not use metric screws on an American gun..... just wouldn't seem right to me and quite honestly, the difference is too small to matter. Best to keep things simple and not over complicate them.

 

[WR Moore]

I've never tried it myself, but Loc-Tite does make a product that acts as a thread former. I do know that it saved someone I know from a massive repair bill on a John Deere that would have cost thousands.

I'd go with Protocal Designs fix.

 

[2152hq]

Are there enough threads on the screw exposed on the inside of the frame when the screw is installed full depth for you to have threaded it thru a (thin) nut to keep it in place?
..and not have that interfer with it's job of placing tension on the mainspring of course.

If not, I might try one of the expoxy 'steel' bedding compounds in the stripped hole and 'bed' the screw in it w/ release compound. Making new threads in effect.

Or simply retap to 10-32 or the slightly smaller Metric size mentioned already.

The frame, tg & bbl are in the way of swinging a tap wrench around 360*.
You'll need a long tap extension to reach the hole in the front grip strap. Or do it in increments w/ a slide thru handle wrench.

I wouldn't bother opening the counterbore up if going to 10-32. Just turn down the head till it slip fits the orig counterbore.
Whatever head you are left with is more than adequate.
Use a drop of Green Loctite on the screw when final assembly is done if you think it may back out on you.

 

[625-7]

Another alternative is an 8-32 heli coil. Kits do infact exist