The missing screw...

[mhuss]

Sorry, this is a real newbie question: I have ETA movement 251.252 (an older model), the technical communication tells me the missing screw is part number 58502. Is it possible to find one of these screws without finding a donor movement? And how would one find a donor movement? I can get a new movement for $120 or so, but that's an expensive way to get a missing screw! Thanks...

[oldhippy]

I don't have the tec sheet, what is the screw missing for. You can normally by a selection of screws from any good watch materiel suppliers 

[mhuss]

Thanks. The Tech Comm just says 58502 and 15.142.01, no mention of size. Do you suggest just buying a screw assortment and finding a close match? 

[Knebo]

Hey @mhuss, welcome to the forum.

So you checked the correct part number of the screw in a document like this?: https://shopb2b.eta.ch/technicaldocuments/index/pdf/id/2104/

If you have the right reference (movement number AND part number), you can be sure that it'll fit. There's usually no size specified. Better get the specific screw.

With an assortment, you'll be trying forever and most likely will damage the thread in the process -- and then even the correct one may not fit anymore. And you probably still won't have a properly fitting one in the end.

[Waggy]

On 5/14/2023 at 2:01 PM, oldhippy said:

You can normally by a selection of screws from any good watch materiel suppliers 

I would agree that you can usually find a screw that will do the job in a selection pack and pay pennies rather than getting a whole movement, as long as you are careful  and don't get too heavy handed. I's my golden rule of watchmaking, If you have to use force for anything you are dong in wrong and will regret it! 

I first I sort through my selection of spare screws and find a few that look about right: head size, length, thickness. Then from this 'short-list' I pick the one that looks closest and give it a try, if I feel any resistance then I stop and put it to one side (see golden rule above ), and use what I have learned to select the next candidate. Unless you force in the screw I think it unlikely/unlucky you will damage anything.

[Knebo]

15 minutes ago, Waggy said:

If you have to use force for anything you are dong in wrong and will regret it

that's good advice --both generally, and particularly if you a trying various screws.

 

On 5/17/2023 at 4:08 AM, mhuss said:

Thanks. The Tech Comm just says 58502 and 15.142.01, no mention of size. Do you suggest just buying a screw assortment and finding a close match? 

Sorry, when posting my link above, I didn't realize that you had already done all your homework! So you have the correct part number. If you find that reference number, it'll fit. But a quick Google search indeed showed me that it seems hard to obtain that particular screw... tricky one. You may indeed have to try your luck with an assortment.

Good luck!

[mhuss]

Thanks for the suggestions. I found on one doc that this screw is the same as the a much more common 54402 - it just arrived, so I guess I'll see!