I searched for it under picture framing thinking it might be used for sizing matting but struck out there too.  Having a small rack and pinion adjustment and then hand stamped numbers sounds like it may have been repurposed but from what?

I am kind of stuck on the whole solid brass thing, why is anything solid brass? Because it is exposed to high moisture or water correct? Solid brass = ships instrument? Mapping tool?

12 minutes ago, John Morris said:

I am kind of stuck on the whole solid brass thing, why is anything solid brass? Because it is exposed to high moisture or water correct? Solid brass = ships instrument? Mapping tool?

 

That's what I thought and searched for it under navigation tools and struck out there also.

 

I also thought it might be an early slide rule and came close there but no cigar.

 

Cool research source Dan, love the graphic. It may have already been mentioned here, but it also appears to be some sort of gauge that should attach to a machine.

9 hours ago, John Morris said:

I am kind of stuck on the whole solid brass thing, why is anything solid brass? Because it is exposed to high moisture or water correct? Solid brass = ships instrument? Mapping tool?

Or it was simply easier to work with than steel. Or readily available.

John