Any ideas? Thanks much,

Any maker's mark on the device?

No makers mark or pat numbers. 

Looks to be aluminum.
Is it?
If so, could be some sort of drafting protractor with missing parts.

Looks like a very cool lay-out tool. 360º, adjustable diameter,  tangent offset at diameter.  I could think of a lot of lay out work for that tool if I didn't have a computer with a good cad program.

Chilly

Is it part of a pantograph engraving machine?

Looks like the typeface letters could be fitted in the wide slots.

Someone on a machinist board ended up buying it for some very old engraving machine (Gorton 3U I think).

It found a home and I guess I was on the right track with the engraving idea.

Thanks all,

A happy ending