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.
First I cut out a piece of brass from some brass off-cuts that I had left over from my enamel box development. I've not written the enamel box development, but I might do in future if I revisit it. The development took me a long time as I was quite new to machining and so I've lots of scrap off-cuts.
I cut the material as near to the marked-out circle as I could,
Then I cut off the corners too and then put the piece in the lathe chuck to cut it round. The four holes you can see in the picture, above, are the clamping holes I used for securing the brass plate when I cut out the mounts for the enamel box. It was quite a wasteful method of making the mounts, to cut them from solid brass plate!
Back to the subject, yes, in the chuck, put on the lathe and turned to a nice circle. The very top picture above shows this turning. I'm using some cutting fluid here, hence the smoke. The brass plate is cut to leave some material next to the lathe chuck, as can be seen here:
which is for the inner section lip that will hold the piece in-place within the middle watch section. I didn't need to raise the piece off the lathe chuck by cutting it this way, which at the time was a problem, I've since solved the problem (see my disqus comment about using a lathe spacer to raise the work off the back to avoid crashing into the clamps).
Ooo now I've left a bit out! The brass plate was first drilled out in the centre by using a drill held in the lathe head-stock. I used a progressively larger drill until I could get the lathe graver bit into the inside to make the cut. Once I'd got that to the correct diameter I re-clamped with the clamps on the inside and cut the outside, as seen in the pictures above.
Once very very close to the correct dimensions I finely adjust with wet'n'dry paper
which mostly just polishes the metal and gets rid of the tool marks.
I check the fit with the middle watch section
Yes it's good.
The top of the inner watch section is going to sit on the shelf that is mid-way down the inside of the middle watch section. So it needs a lip to stop it falling all the way through but also needs to be just the right diameter so it doesn't restrict the closing of the top watch section - if you get my drift. So I cut that next
With this cut I don't need to raise the work off the back of the lathe chuck because the work extends beyond the clamps.
The back watch section fit needs to be considered. At the moment the inner watch piece is too thick and prevents the back of the watch from being closed so I shave a bit of material off the back now
Putting the ring in the other way, I do a little be more cutting of the lip until it is the same diameter as the dial and also shave some height off it. Here I'm just doing a sense check:
The ring is done, for now, and looks like this:
Putting it inside the watch to show the fit:
The inner ring has been inserted from the top, so the lip on the ring stops it from moving any further down.
So I construct the watch
but found I couldn't get the back section on with the inner section in place. So I had to adjust the inner watch section some more:
So I reduce the diameter a bit at the bottom,
and reduce, again, the overall height
Now, after those adjustments, the inner watch section looks like this:
and all the watch sections fit together nicely!