I have been working on converting my charter oak 12Z mill to cnc for many years now. When I started, that was pretty much the only way to get a cnc mill in that class short of buying an industrial machine. Today, I feel that would be a mistake. There are several cnc machines already ready already, so unless you really want to learn from the process, it is IMO not worth the hundred plus of hours to convert a bed mill. I'm pretty sure that without including labor I have spent as many dollars as I would to now buy a turn key machine.