2023-12-16

Last modified: 2023-12-16 21:25:17

Watch design

I'm starting to wonder if having the mainspring barrel wrapped around the outside of the watch is not such a good idea after all. Arguments against are:

• it requires the mainspring to unwind comparatively slowly
• it takes up a lot of space

Perhaps we could retain the most obvious feature of the design (rotate the case clockwise to wind and anti-clockwise to set time), if the mainspring barrel were instead of a more ordinary design, and the hour hand was on a separate gear. So the bit that you wind would have teeth on its inside which engage with teeth on the outside of the barrel.

We could still have the same type of 12-hour stopwork, except now it would be effected by having a peg on the winding gear hit a peg on the barrel outer (or, maybe just 1 tooth gap filled in solid, if the teeth are strong enough).

The extra complication then is that there needs to be an extra gear that turns slower than the mainspring barrel, while the rest of the train turns faster. And not only that, but this extra gear has to be in the centre of the movement. But it does mean we don't need fancy bearings for the barrel.

Given that the barrel will turn so slowly, maybe simple large plain bearings is fine and pivoted rollers is overthinking it.

Another thought I've had is that perhaps banking the pallets against the escape wheel doesn't give you enough control. Maybe it is a good idea to have adjustable banking pins of some sort after all.

And maybe I should try to acquire some screws smaller than M1.6.

And maybe I should just make something driven by a coiled spring, just for the experience.

So, threads I have are:

• make something powered by a spring
• make a gear cutter from 3mm round silver steel
• make a high-ratio geartrain in some plates

And then I can put these together to make a "Nuremberg Egg" type movement, and then make everything a bit smaller, use a proper escapement, and put it in a wristwatch. Easy peasy.