It is not hard to thread iron pipe, like said above, lots of cutting oil, get a gallon.
Most china machine tools seem to work well, even name brands use china parts. Copper is too expensive and generally not recommended for air pressure it will corrode from inside. Put a few ball valves in line, and lots of "T's" with plugs so you can make new attachments later. You can also plan your runs to use pre-cut lengths and nipples as I have done many times. Use couplings not unions to connect your pipe joints, and a good pipe dope or Teflon tape to seal. Also blow the line out real well before you hook up tools.