I wanted to start bending up some hard lines for my '72 as well as some other projects. I bought 10' of stainless 3/8" (AN -6) along with tube nuts, etc. and took my Summit Racing AN flare kit to get started. Others have reported they could flare stainless with this Summit or other similar "cheap" flare tools, but I honestly can't see how - I could not get ANY flare in stainless with these tools.
I then ordered the Rigid 485R racheting 37-degree flare tool (catalog number 41162, Model Number 377) from Inline Tube (inline P/N TLF01) for $125. This tool works PERFECTLY and makes beautiful flares in the hardest stainless with no effort at all. This model does 3/16 (AN - 3) to 3/4 (AN -12) lines which covers every automotive need I can think of. I HIGHLY recommend this tool - it' ain't cheap, but it makes hardline flares easy.
http://www.inlinetube.com/Straight%20Length/tools.htm
http://www.ridgid.com/catalog/RT2004-076.pdf
This is the tools I used and initial results...then things kind of went wrong but that's another thread
