all- I bought out a garage estate awhile back that was untouched since the 50s. This part was mounted onto the table. It just says "Duplex" and spins almost like a lathe. Big round thing is removable too. What the heck is it?
If it didn't have the big disk you could almost mistake it for a pencil sharpener!
It appears that it may have internal gears? Does the "big round thing" turn appreciably faster than the handle revolutions? I've seen old grinding wheels like that, a good heavy wheel, once up to speed, is easy to keep rotating as you grind. Also, if you Google Duplex Grinder, you'll see that was/is the business that they're in.
Any girl could tell you it's a "Thingy".
Sorry, I couldn't resist.
Does the crank handle move in and out.
It may have two speeds.