I recently had an enquiry from a customer who was worried a watch they had bought was waterlogged and rusty inside - not an uncommon problem, unfortunately! Fortunately this was not the case, and the movement and dial were both in good condition - the problem instead was the movement ring was incorrect and too small to support the movement, and so the last ‘repairer’ (or watchbreaker) had glued the movement into the case and this was visible through the glass. Digging this out to release the movement was a laborious task and new movement ring would need to be made to hold everything in place correctly. As you’ll see this is not just a simple ring shape!
For the purposes of case fitting, a watch movement has three sections, the dial side, a fitting ‘lip’ and the movement side, all with different dimentions which must be measured accurately to hold the movement in the correct place. I started by boring out a section of bar to fit the movement side, then I could cut a wider section for the fitting lip to sit on. At this stage the distance both above and below the movement were oversized so I could make adjustments later.
Once I was happy the movement fitted snugly, I could cut a slot for the stem. the crown tube extends into the case, so I cut a slot that would fit around this with a small amount of movement room, 0.5mm each side, and 0.25mm above. It was important for the top surface to be left uncut both for strength, but also as this would be visible once the watch was assembled.
Once the ring was parted off it could be tested in the case. You can see the seat for the movement on the inside and that the ‘front’ of the ring is still oversize and needs to be brought level with the case.
Once the critical dimensions for fitting were all reached, the next step was to make some small cuts in the back side, which would allow case screws to securely hold the movement in place. These were made will a milling cutter in the Hauser Jig Borer, which allowed me to locate the cutter exactly centred with the screw holes.
With all the machining complete I could do a test fit in the case with the glass. It looks great in terms of fit and securely holds the movement in place. At this point the work could be finished, but as the ring was visible I wanted to make it fit better with the rest of the watch - nickel plating would change the colour to match the steel, and protects the ring from discolouration in the future.
It was a fairly complex job to make this component to a high standard, but definitely worth the work. In the photo above you can see the old ring was in no way fit for the job and it’s a shame the previous repairer had such low standards. Now it’s been done properly the watch can be enjoyed and looked after correctly for many years to come! After the service a new Hirsch strap was finished and the watch had a whole new lease of life.
