I did this for another board where it seems to come up fairly often thought it may be helpful to people here also.
Many people seem to be afraid of making double flares in steel lines, like brake lines. Here is a how to step by step with pictures.
Here is my cheap imported double flaring set. I think it was about $15. For the small lines it works fine, 3/8 and larger its not so good so if I was going to do many larger lines I would spend the money on a better quality tool.
Here is the tubing cutter I find to be the most useful for stuff like fuel and brake lines because it works in tight spaces. I got it at an autoparts store, I think it was about $20.
I have found with the cheap tools a bit of lube helps a lot.
First step is to measure and cut the line to the proper length.
Next step is VERY IMPORTANT. Install the fitting nut!!! Or you will be cutting and flaring again because you cant get it on once you do the flare.
Insert tubing into proper hole with the end sticking out of the side with the bevel and lightly tighten the clamps.
This is the flat side that should be the long side of the tubing.
This is the bevel / countersunk side that the end of the tubing should be sticking out of
Now you set the height of the tubing out of the clamp by setting the proper die with the tip up. The proper height is the first step of the die.
Now tighten the clamp nut closest to the tubing then tighten the farther one. This is important because doing the farther one last will give you more leverage to get it tighter. When they are tight the bars should be touching the full length.
Now insert the proper die with the tip down
Start pressing into the die until the die contacts the bar
Remove the die
Start pressing into the bare tube until it fills the bevel in the bars
Remove the tools and you are done.
