Double Flare 101.
the first important step is getting a perfectly square cut.always use a tubing cutter,hacksaws and zipcuts will not do.the bigger one in the foreground is a very handy tool,the smaller one in the back is for tight spaces,like when you have to do a brakeline on the vehicle(not a nice way to do it,i don't recommend it unless theres no other way)
the cutter has this reamer in the handle to open out the cut end.
the pin on the upper die should slide easilly into the tube and sit square.if it's tight,more reaming is needed.
now,slide on the fitting.i don't know how many times i've forgotten this step and had to cut off a freshly formed flare to put it on.
whenever possible,use a vice to hold the clamp.this will make life a lot easier.
the dies have this little step on them....it's not there just for looks,it's to measure exactly how far the tube needs to project from the clamp.not approximately-exactly.
make sure the clamp is tight-both ends.set the die in place,and the press on top.twist the press frame clockwise on the clamp so it can't move when turned.look close at the die to make sure it's perfectly parallel to the clamp face.if it's not,slide the press to correct it.
tighten the press down SLOWLY,watching the die to make sure it's going straight.also,make sure the tube is not sliding in the clamp.tighten down completely.
remove the press and die...you should have something like this.
reposition the press(without the die)and turn clockwise as before.press down the flare.don't get too carried away with how tight it is-you don't want to squash it out too much-just press it down.
remove the press,it should look like this.
now undo the clamp....ta-da!
one perfect double flare.
don't worry about how long it takes at this point,it will get quicker with practice.and a line that took a little while to make properly is less likely to make you dead than a quick and sloppy job.