Thickness Gauge?

[Tomc938]

This showed up on Marketplace. My GUESS is that it's a caliber for measuring sheet stock? $5 is a good price for a chocolate bar now a days.

 

[Mcgyver]

The look like watchmakers proportional calipers. Not that watchmaking would have an exclusive on such a thing, but that's where I've seen them often enough. I've not used a pair (but may have one somewhere) and am not sure if they are yesterday's tool or have some highly valued special function. Measuring the remaining plate thickness at a counter bored hole? Just a guess but a common feature in horological parts.

 

[trevj]

The look like watchmakers proportional calipers. Not that watchmaking would have an exclusive on such a thing, but that's where I've seen them often enough. I've not used a pair (but may have one somewhere) and am not sure if they are yesterday's tool or have some highly valued special function. Measuring the remaining plate thickness at a counter bored hole? Just a guess but a common feature in horological parts.

Yeah, will second that. Lots of this style was made for watchmaking or watch repair purposes, where you could very quickly measure, accurately enough, the thickness of various parts that needed reproducing.

Of course, few outside the Watch Repair lot, ever need a caliper graduated in "Lignes" either...