New to the Horology world I was reading my Complete Price Guide to Watchs and ran across all the units used to measure watch movements can someone tell me what the preferred unit used today is??

Thanks Jay

American movements are almost invariably measured using the Lancashire gauge as shown on page 34 of the watch guide, although there are variations the vast majority were made to standard sizes and fit nicely within standard size cases. The chart there shows from 18/0 through 20-size movement sizes.

Most of the more common American pocket watches we collect tend to be 12, 16 or 18 size. Some exceptions to this will include 10, 14 and 17 size, as you see in the listing there were even some early 20 size watches and you will find some "in between" sizes as well so at times this can be confusing.

Swiss and other watches are commonly measured in lignes.