Toastmaster router

It looks like the style that uses the black twist ring to raise or lower the motor into the base

G'day and welcome to the forum.

As Doug said, It looks like the style that uses the black twist ring to raise or lower the motor into the base.

Based on an older model fixed base router....

How does the twist ring change the height? It's loose enough to spin well enough, but nothing else moves. I don't have a manual, either, so I'm groping in the dark

Welcome to the forum.

I think if you twist the ring far to the right, your toast will be darker. If you overheat the thing it'll be toast itself.

Turning the ring should raise or lower the motor compared to the base. That changes how much the bit protrudes below the baseplate (depth of cut). Some fixed-base routers also have a lock but I'm not sure that kind does. There should be threads and that ring should move on the threads like a nut does on a bolt. Perhaps it's thread are stripped? There's a manual here for a Craftsman router that adjusts height in a similar way. Maybe that will be of help.