Screws

[Bonefixer]

Following advice on here I’ve bought a few watches on eBay to practice my skills. One was non-functioning - didn’t run, couldn’t set hands - and when I opened it up it was obvious why. A previous tinkerer presumably had part dismantled the movement and just stuffed it back in the case. The rotor was free, as was the train wheel bridge. 
 

It’s an AS 2063 caliber. I’ve found the parts list and I think everything is there. What I’m struggling with is screws. Some were loose in the case, I don’t know if I’ve got them all, and I don’t know which screw goes where. 
 

Apart from trial and error, is there a good way to identify the right screw for the right bit?

[Poljot]

If you've got his "Parts List" - there should be no difficulties identifying which screw goes where:

https://www.cousinsuk.com/PDF/categories/645_as2060,1,2,6,4,6.pdf

Each screw has the part number and description.

[Bonefixer]

7 hours ago, Poljot said:

If you've got his "Parts List" - there should be no difficulties identifying which screw goes where:

https://www.cousinsuk.com/PDF/categories/645_as2060,1,2,6,4,6.pdf

Each screw has the part number and description.

That’s very helpful, thank you. Far more detailed than the parts list I’d found elsewhere which didn’t go into detail about which screw went where. 

[mikepilk]

This may help

 

[JohnR725]

one of things helpful to do with screws is to arrange them in groups of identical screws. Usually once you have them all together ill become apparent what at least most of them are for. A lot of the components like the pallet fork bridge will either have one or two screws and those screws will be different etc. so you usually have the bigger category the plates screws and it makes it a lot easier if things are in categories.

 

[Bonefixer]

Just came back to this movement - I’d got it running but the date mechanism wasn’t working properly. Quickset was fine, but it didn’t change at midnight. 
 

The issue was a screw. The date indicator driving wheel is screwed into place and the screw for it was missing. I used a random one that seemed to fit, but it doesn’t hold the wheel down properly and it doesn’t work. If I push down on the wheel with a plastic stick then it works as it should. 
 

Conclusion - wrong screw not doing the job. So I bought a replacement wheel plus screw only to find it won’t fit. I think my wrong screw has partly stripped or otherwise damaged the post the wheel sits on. Can I re-tap the thread to suit a bigger screw? How would a real watchmaker solve this?

[Mercurial]

The screw in question is part 33.020.01. 

Have you carefully compared the screw you’ve used with the picture of this part in the tech sheet linked above?

If you’ve accidentally used a similar but incorrect screw, it would explain the problem. For example if the screw you used is a bit long, it could be bottoming out before it holds the part down securely. 

It is hard to suggest what to do until you know whether you’ve used the right screw, and if it is the right screw, why it isn’t holding the part down correctly. 
 

EDIT : I missed that the original screw was missing. Given you found a random screw that fits, but doesn’t work correctly, I suggest you work out why it doesn’t work.

If the screw is too long and bottoming out before it is holding the part down properly, then consider stoning down the screw until it works.

Study the screw from the parts sheet and compare it to the one you used - are there any obvious differences?

Hope that helps,

Mark

Edited July 13, 2024 by Mercurial
Missed important information in the OP’s question.

[AndyGSi]

I think the key point learnt here should be not to just use any random screw that seems to fit.

Moving on, the question would be as per @Mercurial is have you got the correct screw now and how does it compare to the screw you used.

[Neverenoughwatches]

4 hours ago, Bonefixer said:

Just came back to this movement - I’d got it running but the date mechanism wasn’t working properly. Quickset was fine, but it didn’t change at midnight. 
 

The issue was a screw. The date indicator driving wheel is screwed into place and the screw for it was missing. I used a random one that seemed to fit, but it doesn’t hold the wheel down properly and it doesn’t work. If I push down on the wheel with a plastic stick then it works as it should. 
 

Conclusion - wrong screw not doing the job. So I bought a replacement wheel plus screw only to find it won’t fit. I think my wrong screw has partly stripped or otherwise damaged the post the wheel sits on. Can I re-tap the thread to suit a bigger screw? How would a real watchmaker solve this?

Screws may look to fit initially,head size, shank and thread diameters. But a lot to do with the thread can affect how compatible it is with it's joining thread. Different thread angles can make a tight or loose fit but the big one is making sure they have same pitch, get this one wrong and a turn or two in you think its ok, another turn and one or the other is going to begin stripping back and its nearly always going to be the one thats the hardest to fix. A well fitting machine screw should only need a light touch to be driven in, no force at all required.