Tag archives: watch-case

I've been working on making a watch case. It's still a bit rough in places so plenty of room for improvement! At this stage I've not got the movement fit or, as you can see, any hands.

The watch movement is considerably smaller than the watch case I've made, so it will need some sort of holder to secure it in place. I'm making this ring from solid brass, so a bit different to the other method of making the ring from a bar, soldering and hammering into a ring.

I've been a bit worried about how to put on the strap for some time. I don't want to drill a hole all the way through the lugs and it seems impossible to get a drill access to put in a blind hole on the inside of each lug.

But, as with nearly all of this project, I don't want to think about it too much! I'll just do what I can and, by experimenting and making mistakes, the solution should present itself. It's rather like thinking with my hands.

The base fits snugly into the middle watch section but it's going to need some screws to make sure it stays fixed. I'm using the middle watch section to position the mill table, using the previous holes as guides and a wiggler to centre the spindle.

I'm going to curve the back section to get rid of the right angled edge. I've written this g-code routine already for the top watch section so I'll use it again. Strictly speaking the back section is not supposed to be an ellipse shape, but if I tweak the parameters then it becomes a very shallow ellipse and will be fine for this initial design.

I'll be using a flat watch glass for the back section which is quite a bit smaller, in diameter, than the front watch glass. First, though, I cut the back ring diameter to match the middle watch section.

Now the ring is made it needs to be fit into the middle section.

In this case I'm cutting the inside of the ring first, to get this fully concentric, and clamping the outside. There is no particular preference or benefit of doing the inside or outside first since both should be near circular from the hammering.

To cut the ellipsoid shape into the top ring section I've programmed the ellipse in g-code so that the lathe table will follow this shape. The cut gets incrementally closer to the final cut. In the diagram, above, the solid white lines are the tool paths yet to be followed and the red ones are the paths already done.

On the final cut I increase the lathe spindle speed to give the finest finish.

The top ring section is made in pretty much the same way as the centre section. I get a bar of brass and bend it into a ring and solder the joints. This technique is worth developing here because it can be extended to precious metals even though, with brass, the relatively inexpensive cost of the metal means the ring section could be machined from a solid piece of metal.

The ring, now with lugs attached, goes back on the lathe. Since I'll be cutting the outside of the watch I put the clamps on the inside of the ring.