Hello everyone! Been a while!
I was given this by a friend. It was pretty locked up, so I've freed most of it, but I'm not exactly sure what I'm looking at. It looks like a metal brake, but it is way more complicated than I've seen. It has these sort of weird, double roller hinges? The top jaw has a slide that you can move back and forth to adjust how much room the top jaw can slide up or down... and it also has this dial in the front. When you turn the dial, little metal tabs in the front move in or out. One of them (on right) has graduated markings on it. When I removed the bottom blade, the tabs that move in and out are connected to a row of teeth. When the tabs are fully in, the teeth go to a slotted section on the back. The bottom blade totally covers the teeth when installed, and seems unaffected by their movement.
What am I looking at?
https://imgur.com/a/0l87xYVThanks!