Just my two penn'orth, I've joined copper to the steel pipes on the Galaxy, it can be done with care.
Use a pipe cutter, as BrianH says above, and a pipe bender is useful if you want to make a neat job.
Use grease when flaring the steel, make sure it's clamped tightly, and use a good flaring tool - the cheap anvil types are hopeless for small pipe. Make sure you put the male end on the steel pipe, that way you don't have to do the double flare on the steel.
For a cheap flaring tool, I would recommend the Franklin AF2003 / Powerhand type, the idea is a copy off the old Modprod Easyflare - they don't look much, but they do work really well.