Thanks for the lead on the watchmakers/jewelers caliper.  I do believe
it is a jewelers Jo-Di caliper, but a brief google search reveals little
historic data.  My question to those in the know, what is the side scale
with stop for?  The lines are in increments of 3 going up to 36.  The
lines are not millimeters, however every so often a line will fall out on the
metric scale?

https://www.flickr.com/photos/122649122@N.../46513898665/in/album-72157
677299550057/">https://www.flickr.com/photos/122649122@N.../46513898665/in/album
-72157677299550057/

Thanks for the knowledge!

Jason