Puw 500 screw hole stripped

[Johndub]

Hello all, 

I've got this old puw 500 movement, the crwon wheel screw hole in the barrel bridge appears to be stripped. 

Are there any quick and dirty fixes for this? Don't see any source of donor parts online, and don't have the tools to do any real metalwork, so I'm thinking something very basic as a fix. 

Tinfoil, superglue, rubber cement? Something like that? 

[HSL]

The tube on the PUW 500 where the crown wheel is fastened  is so flimsy so probably there isn't any good fix for this problem more than replace the bridge. 
There is a similar one as yours on the bay for parts.

 (https://www.ebay.com/itm/PUW-500-watch-vintage-mechanical-movement-parts-or-repair/114410464379)

[rodabod]

The crown wheel screw enters the barrel arbor. Or do you mean the main plate?

[HSL]

I think he means the crown wheel on the barrel bridge (105), at least it is what it says in the text.
The ratchet wheel comes on the barrel arbor, hence the square hole.
But one never knows, just in case I put a picture of a PUW 500 I found in the scrap box, seems an over enthusiastic German watch repairer put a PUW tag on the bridge...
 

[Johndub]

Thanks for the responses. Hsl, yep, the crown wheel is the one. Didn't think it was salvageable, will probably have to buy that ebay one. The watch isn't fancy, i got it as part of a job lot of old bits, but I'm having fun getting them back up and running where i can, learning a bit with each one

[HSL]

It isn’t always the monetary value in a watch that makes or breaks what one does with the watch.
I have quite enjoyed working on plenty of German PUW powered watches just out of the pleasure
of maybe seeing some “new” technical solutions they tried to introduced on them. I can’t deny it’s been great fun.
That’s why in quiet I nowadays admire Andy Hulls enthusiasm with his 404 club, just great fun.

[Johndub]

Absolutely. I'm a near total beginner, and even though all I'm working on are pretty cheap old things, there's a lot of satisfaction seeing them run again, especially the older ones. 

Hopefully this will be one of those 

[rodabod]

Apologies! I thought you meant the ratchet wheel, despite me saying crown wheel! Sorry. 
 

The only other option which is fairly trivial for clockwise screws is to up-size and the-tap, which you can often do with the new screw if it’s going into a brass plate. Not so easy with left-handed crown wheel screws. 

[Johndub]

No problem rodabod, appreciate the input 

[Tudor]

If it grabs at all, the tensile load on the crown wheel screw is rather low. I would try some locktite on it, and tighten the screw as much as possible. Then let it set overnight before completing the assembly and winding the watch.

That might do it...

Another "kluge" repair might be to fill the hole with epoxy, let it cure, and then drill and re-tap at the original size. That requires a nice set up- I'd align the tap drill on the drill press and do the epoxy fill right there. Then drop the tap drill in to open the hole once it's cured. Then swap to the tap and run that through also with the drill chuck (by hand), to keep everything in alignment. At that point, solder might not be a bad idea actually...

Edited September 28, 2020 by Tudor