Hi jacobbiljo, Good to see a bit of enginuity I am just wondering what tools you have at your disposal? Sounds like you have access to a mill but it is possible to build a milling machine from scratch even without machine tools as described in the books, Build Your Own Metal Working Shop From Scrap series written by David J. Gingery. Looking at your preliminary drawing I could only imagine that you intend to do light machining, the base needs depth. As far as your spindle goes I would suggest taper roller bearings to take the load. "Precision" taper roller bearings are expensive so I would use just a generic off the shelf taper bearing unless you really need it. Your motor has plenty of power but don't use the motor shaft as the spindle output unless you only want to do light work. The motor bearings are not meant for it. I work as a structural fabricator and machinist. It would be easy to pick up some nice big bits of Parallel flange channel for your bed from your local industrial area as any offcuts of beam gets tossed anyway. The roller guide idea is a good one as far as precision goes and for a small mill it could be quite serviceable. Your design might be ok as is for "light" work but vibration will be your biggest enemy. Have fun and I look forward to seeing this thing when it is done.