Not even sure if it's a tool

The top part with the graduations (O..30..60 ..90..60..30..0) spins
The screw coming out of the larger part pins the top so it doesn't spin

Nevermind
It's the file holder for a "SPEED CORP CIRCULAR SAW SHARPENER, PORTLAND OREGON"

I must have hit something wrong when I googled it before posting the question