I feel like I knew what this thing was right up until I had one. Two tool id site had no idea, and one said it’s a ball joint separator, but I can’t find any that look like this, and I swear I’ve seen them in stores, but can’t remember where.
Maybe a type of bearing press?


Definitely a flaring tool for creating flared ends for copper or soft metal tubing. It was a tool they were still teaching us to use in automotive classes in the late 1980s.
We still use them all the time in HVAC-R for refrigerant piping. Flare fittings are one of the best and easiest ways to have a reliably leak free but still easily removable connection.
I got really good with one because when I was young I’d always forget to put the flare nut on first lol. End up doing it twice every time. My uncle used to get pissed.