Quote Originally Posted by shutterfinger View Post
Pressure arms from an early wet plate camera/developing station?
This is what I think they are... hold-downs for plates/paper on a board used as a coating station.

They could also be used on a copystand to hold squirrely copy such as loose pages or books open to the page you are copying.

The fact one of them seems to have a wire soldered to it makes me think whoever used these before might have been doing some copperplating and used one to make contact with electricity.