there are a few rotaries on ebay that look ok for light milling . the belt driven are worth avoiding unless a guy modifies it, there is too much shaft flex and belt stretch . I bought a 100mm quite a few years ago for light jobs and after looking it over I tossed it on the shelf to be stripped and salvaged for possible future projects

Thats interesting on the torus , I hadn't realized there was that one in between the other mills they offered . Curious if you got the advertised travel , mine is no where near it