I got a pocket watch recently, and as is natural to me I find myself gravitating to the technical aspects. (Wikipedia) For instance, Railroads demanded very specific standards for their time pieces, lest a train derail from being off-time by a couple minutes. Therefore there are specific watches which are engineered to be very robust and keep time much more accurately.
There's even technical words which i've never heard of before, such as 'isochronism' - keeping the same time even if parts of the whole start to change. Apparently this is even used in some modern technical documents; USB has an isochronous transfer mode.
One of the things that stood out was how temperature changes the operating of the device. Extreme cold or heat will contract or expand the steel balance, causing the watch to run slow or fast. They engineered a solution which involves mating it to a brass balance and having two cuts in both, though that leads to only keeping accurate time in either extreme cold or hot environments. Special alloys ended up fixing the problem for good, though that was post-Victorian, essentially.
You could even extend some knowledge of watchmaking to other parts of a story. Jewels are often used as a hard, durable, low-friction mounting point for the moving pieces of a pocket watch. You could include in your story a plot device where one particular jewel (though normally valueless) unlocks some key to some device made thousands of years ago, as part of some detective novel revolving around ancient devices with a modern spin.
There's a plethora of technical jargon specific to pocket watches which might be nice to include in the story. If you want to write for geeks/nerds, including technical details like this can't hurt.
Some neat facts:
- Wrist watches ('wristlets') were considered feminine and unmanly until they were introduced by the military and finally made standard issue in the 1940's.
- The vest-pocket in a three piece suit is intended for a pocket watch. Since vests fell out of fashion, the only place to put a pocket for a watch was in trousers. Hence that little pocket you tend to put change in or try to cram a cellphone into.
- A four-minute delay in one watch caused a train wreck, hence Railroad chronometers will (among other things) keep time to within 30 seconds in a week.