Stuck screw

[handwound]

Hey guys,

I‘m trying to remove the lower balance end stone of a movement I want to service, but I can’t get the screw that holds it in place to turn. Any advice?

[jdrichard]

8 minutes ago, handwound said:

Hey guys,

I‘m trying to remove the lower balance end stone of a movement I want to service, but I can’t get the screw that holds it in place to turn. Any advice?

Is the Screw slot too shallow?  TRy pressing down hard with the screwdriver (make sure you have a grig in the slot) and use a pare of vice grips to turn the screwdriver while applying top pressure on the screwdriver.  Please dont slip.

[handwound]

Yes it's really shallow and narrow. I tried to press it down more, but the screw just twists the blades of my screwdrivers. 

[jdrichard]

10 minutes ago, handwound said:

Yes it's really shallow and narrow. I tried to press it down more, but the screw just twists the blades of my screwdrivers. 

Should be a slot in the screwdriver blade that the tightening screw will hold??

[handwound]

that was probably misleading. The blade itself is fixed in the scewdriver and doesn't turn, just as it should. But the tip of the blade gets twisted before the screw starts to turn. 

[jdrichard]

13 minutes ago, handwound said:

that was probably misleading. The blade itself is fixed in the scewdriver and doesn't turn, just as it should. But the tip of the blade gets twisted before the screw starts to turn. 

Can you put some oil on the screw and leave it overnight, then clean off and try again.  Dress your screwdriver so it exactly fits the slot.

[handwound]

Thanks, I will try that

[handwound]

well the trick with the oil didn't work. I think the next step will be to get some harder screwdriver blades and try again. 

[WellAdjusted]

These screws are easily stripped, and it was a common problem back in the day. As an aside, Hamilton in its later watches had threads in the cap jewel setting, with the idea that it's easier to deal with a stripped setting vs a stripped main plate.

Anyhow, I'd recommend heating and cooling the piece. The steel screw and brass mainplate will expand and contract at different rates.

If you have a heated ultrasonic, run it as a high temp for around 20 minutes. If that doesn't work, rinse it, freeze it, let it come back to temp, and repeat with a heating cycle.

[handwound]

Thanks, I will try that as soon as I have some steel blades for my screwdrivers. I hope the screws for the setting on the balance cock aren’t that tight