Mainspring Barrel Bearing.

The bearings in a watch are very important. They ensure the smooth movement of the pivots or arbors. They can get pretty worn out, especially if the watch hasn't been cleaned for a long period. Or is overdue a service.


Most modern bearings are normally jewells, and make it the XX amount of jewells most watches state. However, sometimes these are brass, which can cause there own issue. The advantage of a ruby (synthetic man made ruby) is they can reduce the friction dramatically. Which is very important in the running and efficiency of your timepiece.


Brass bearing can -and will- wear quicker than a ruby. The hardened steel rubbing on the brass can cause the hole to widen, and produce a part that is no longer functioning as expected, affecting the performance of the watch.


The mainspring of a watch creates quite a considerable amount of power. Causing a lot of strain on the bearing. If this isn't cleaned regularly tiny pieces of brass can get mixed with the grease. This produces a grinding paste. A strange occurrence being this watch might work well still with this paste filling in the hole. But once the part is cleaned, and this paste removed, problems can be spotted.


This is what happened to this watch. On reassembly the barrel screw was very wobbly. Then the barrel would rub on the wheel, so every time the watch was tapped, the watch would stop.


The parts for this watch are quite hard to come by. An option would be to replace the whole plate. Alas, this was not possible. So option 2? Make a new bearing!


There are various challenges to this, however, the main point is to make the part work as well as possible.


Some challenges:


Making the hole central

Making the part 0.01mm wider than the hole created so I can friction fit it

Making the hole central in the part

Taking more photos so you can understand what I am really going on about


The dimensions of the manufactured bearing was 2mm wide. A 1.4mm hole in the centre. Approx .5mm thick. The width is very critical in this. I need to ensure it fits without removing too much material from the main plate.


After a bit of filing and mucking about, I managed to make a functional bearing. The watch stops no longer! Until the power runs out.


Very pleased with this one. Job satisfaction guaranteed.




The brass bit has an arrow pointing to it.



The part with the square on the right is the part that sits through the bearing.


A great little job.

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