Movement running slow or fast?
Posted: May 11th, 2019, 8:30 am
We have a watch/movement running slow or fast. I assume we are talking vintage here.
Service history unknown? Cleaning and oiling would be a good start. Check for magnetism if possible. If you don't have a gadget, use a compass to see if something weird is going on.
All parts were looking good? Good mainspring, not set? Set the regulator in the middle.
Still running slow or fast?
Running slow, that is a bit more tricky in my opinion. Balance wheel, added timing washers, too many timing screws? Never touch the screws placed 90 degrees from the balance wheel spokes! The ones closest to the spokes are in focus now. How slow? Is there a possibility to shorten the hairspring by loosening the tapered pin to begin with? Try that, if you dare!
Running fast, does the hairspring move back and forth naturally without looking like it has had too much to drink the day before? All turns must open and shut in a uniform way, if it doesn't there may be magnetism or grease/oil making some of the turns clinging together. Clean the hairspring, easily done by lowering the complete assembly into a cleaning solution.
If none of these steps works, staff work is next. I know that this is not for everyone, but it could be good to know.
When you look at a staff pivot, it is either rounded at the tip, pointy or a bit flat.
To make a movement run faster, you will need more pointy pivots to minimize friction and if you want it to run slower you will need to make the pivots more flat to create more friction.
None of these steps are easy, but this is how some of it is done. Hairspring form may present an issue as well, it must be flat and round, no tension up or down to be able to breathe freely, you get the picture.
Service history unknown? Cleaning and oiling would be a good start. Check for magnetism if possible. If you don't have a gadget, use a compass to see if something weird is going on.
All parts were looking good? Good mainspring, not set? Set the regulator in the middle.
Still running slow or fast?
Running slow, that is a bit more tricky in my opinion. Balance wheel, added timing washers, too many timing screws? Never touch the screws placed 90 degrees from the balance wheel spokes! The ones closest to the spokes are in focus now. How slow? Is there a possibility to shorten the hairspring by loosening the tapered pin to begin with? Try that, if you dare!
Running fast, does the hairspring move back and forth naturally without looking like it has had too much to drink the day before? All turns must open and shut in a uniform way, if it doesn't there may be magnetism or grease/oil making some of the turns clinging together. Clean the hairspring, easily done by lowering the complete assembly into a cleaning solution.
If none of these steps works, staff work is next. I know that this is not for everyone, but it could be good to know.
When you look at a staff pivot, it is either rounded at the tip, pointy or a bit flat.
To make a movement run faster, you will need more pointy pivots to minimize friction and if you want it to run slower you will need to make the pivots more flat to create more friction.
None of these steps are easy, but this is how some of it is done. Hairspring form may present an issue as well, it must be flat and round, no tension up or down to be able to breathe freely, you get the picture.
I may have to send you my 605/240 ... it started to run slow, like many minutes slow 
