A Zoner made a precision small mill wtih a high quality router as the spindle but he resurfaced the taper on a CNC ltahe adn made his own collets. Also, if you veer want to do steel, the RPM ranges are just too high. Plus you are restricted to very .... I finally got a reasonable result with an Italian amde ELU router, expensive tohugh. There are good and bad routers for this application. I wouldnt recommend a buy it and see approach, I have a box full of bad ones. ...