Been making my own for many years. Learned before I could drive because my 1st car was free and had rusty lines. Here is some advice:
#1: Buy a good flaring tool. This one is very popular.
http://www.plumberscrib.com/ridgid-2...ring-tool.html
#2:Make sure you have nice clean square ends before performing the double flare. Use a small cone shaped burr to make a slight chamfer on the inner edge. Helps the flaring tool seat evenly.
#3: A cutter can work harden the line somewhat. Anneal with a torch afterward. Or use a saw or cut off wheel instead.
#4: Coiled line can be straightened by rolling between two lengths of plywood.
#5: Affix a cylinder to the flare & tighten a few times before installing the line on the vehicle. Maximizes proper flare formation for easier fitment later.
#6: Nickle/Copper (NiCopp) line is the cat's meow. Extremely easy to flare & bend.
With so many companies selling pre-bent lines these days it seems that fabricating your own is almost a lost skill anymore. As evidenced by so many vehicles having rubber hose running to the carb. Even over hot exhaust.
