To get a good flare every time you need to do the following
Cut the tube with a cut off wheel or hack saw never with a tube cutter. Tube cutters harden the tube.
Put the tube in the holder and file it flat.
Chamfer the out side edge slightly and debur the inside.
Line it up in the tool and put a drop of brake fluid on the little insert where it contacts the tube. do the first bend and then another drop of brake fluid and do the second bend. You can also use copper nickle tubing (NiCopp). It flares like butter and is much easier to form without kinks.
