I am eveluating options for a donor mill for a CNC conversion. I am also considering building one from scratch using epoxy granite, but if I can find a good donor mill that path would be much less painful. I definitely need auto tool changing possibly with BTC type spindle. Most of the existing manual mills are not designed for BTC spindle it seems? I looked at precision Mathews and some other brands in Alibaba and all of them are equipped with non BTC spindle. Can I have auto tool changing with non BTC spindle?