steve_sordy
Wedding Crasher
Watch the video on how to use it and all will be clear. The device is simple, but the technique is important.Just googled the hanger alignment tool, I can make one of those if I figure out how it's supposed to work. Also that won't help with a bent derailleur though will it? Because I suspect mines a little bent somewhere, and not the lower cage.
You are correct that it will not help with a bent mech, but unless you straighten the mech off the bike you risk bending the hanger! The tool will ensure that the hanger remains unbent.