Is there an easy way to figure out the case size for a pocket watch. Sometimes this is confusing. Is there a method of adding some MM to the actual size of the movement.

How about this one:

Numerical Measurements:

Size Movement
(in inches) Movement
(in millimeters)
20S 1.833 46.56
18S 1.766 44.86
16S 1.700 43.18
14S 1.633 41.48
12S 1.566 39.78
10S 1.500 38.10
8S 1.433 36.40
6S 1.366 34.70
0S 1.166 29.62
3-OS 1.100 27.94
6-OS 1.000 25.40

For instance I have a 6s which is roughly 34mm, when measuring a case, which on ebay, most measure the diameter of the case what would be the total. I know if they say its a 34mm case it would be too small.

At the front of the price guide is a method and dimension set for sizing cases. It explains that the size" of the case is measured as the pillar plate outer body diameter under the dial.

That said, all too often, the Swiss "Ligne" AND the "American" sizes are not used in (too) many "Factory" cased watches. Hence the (way too) many varations in 12s, 14s, 16-1/2s 17s, 20s etc.

THEN THERE IS THICKNESS!!! which allows for the many different thicknesses or "heights" of the movements. So BE CAREFUL when buying empty cases as you could be in for a real nasty surprise trying to re-case non 1880's-1940's USA standard 16s-18s types.

Thanks for the information, much appreciated.

Could a dial/movement gauge be used?

What happened to the post and making of the dial gauge?

im

Tim,

I don't recall a post on dial/movement gauge.

I use my imperial sliding dial calipers for a reading in inches. Then plug that data in to the various charts to convert as necessary.

This post has my absolutely most useful and favorite "inches to lignes" conversion chart.

https://ihc185.infopop.cc/eve/f...273901677#5273901677

I know we were talking about case sizing here... but I generally find I get in this mess trying to source crystals. I usually start with a measurement in inches, convert that to lignes. If I can't find what I need using lignes, then I go to the more common crystal chart and convert lignes to millimeters. So, 1.700" = 19-2/16 lignes = 431 millimeters