Dating pocket watches

[RichardHarris123]

I know that dating pocket watches is nearly impossible unless you know the make and serial number but by which date did: full plates, 3/4 plates ect become more common or obsolete?  English lever vs cylinder? Pin set vs keyless works?  Fully keyed, for want of the correct terminology. A rough guide would help. 

[KarlvonKoln]

There's so much overlap, it's a tricky question to answer. Take cylinder-escapements for example: invented by Thomas Tompion as a concept in 1695, but made functional by George Graham in 1726, they still predate the English lever.  But cylinder-escapements were still in use (Derby watches) in 1955.  First there were key wind/key set where the key turned the center wheel boss on the dial.  Then some were made to be set in back, but some still set in front.  Then pin-sets appeared before key sets fell out of fashion.  Lever sets came along but pin sets were still made.  The crown wind & set hit the scene, but Railroad watches stayed lever set for a long while after. I also look at the style of the pendant, and the dial, as trends of the time would affect the design.  But really, to be any more exact, you need to research the watch.

[RichardHarris123]

3 hours ago, KarlvonKoln said:

There's so much overlap, it's a tricky question to answer. Take cylinder-escapements for example: invented by Thomas Tompion as a concept in 1695, but made functional by George Graham in 1726, they still predate the English lever.  But cylinder-escapements were still in use (Derby watches) in 1955.  First there were key wind/key set where the key turned the center wheel boss on the dial.  Then some were made to be set in back, but some still set in front.  Then pin-sets appeared before key sets fell out of fashion.  Lever sets came along but pin sets were still made.  The crown wind & set hit the scene, but Railroad watches stayed lever set for a long while after. I also look at the style of the pendant, and the dial, as trends of the time would affect the design.  But really, to be any more exact, you need to research the watch.

I knew it was difficult but I was hoping for a rough idea, I didn't know that cylinder escapements etc lasted so long.  Thanks anyway.