Well to be honest I don't think I will be making cranksets (it was just an idea) but sprockets for bmx and single speeds are usually made in cnc milling machines. I am not at all interested in making lugs but dropouts and gear hangers is something where I will be using this machine a lot.

as the key to machining hard materials accurately is rigidity but for that you will need something bigger than will fit in a 12 x 8 shed. the machine in the 'sufficiently strong' thread is very good but I'd have my doubts about its ability to machine SS or titanium. SS is 4 - 5 times harder and titanium is 2 - 3 times harder to machine than aluminium.
That was my original worry really whether something this powerful could be done on a small scale or not? I guess there is no middle ground then small machines are only good for wood and plastics and only large scale industrial machines are only good for ss and titanium. Oh well I will wait for what others have to say and then maybe leave this ambition of mine alone. Cheers