on the right track, but probably Hirtz even worse than kidney stones

It is obviously some kind of precision tool like a 3 dimensional plotting tool. If it used in surgery to extract something, I'm guessing that it was used to map the entry trajectory of a gunshot wound so it could be removed safer?

That makes sense to me.

Bullseye... Its called a Hirtz Compass and was developed and used in WWI to help Docs figure out where the bullet ended up and removed without causing any additional trauma. They would use this in conjunction with X-rays to determine exactly where to cut to remove the bullet.

this will probably be pretty easy.

I vintage 1920's era Cajun rocket engine turbo.

(The hand crank makes it Cajun )

Exactly!

You're up, Red.

Looks like some kind of miter jig, perhaps for tubing?