Mark it this time with a sharp scribe, cut again leaving about 1/4" extra.
I thought I'd highlight this little tidbit as well. For your final (i.e.: precise) cut, much over 1/4 and the metal is just doesn't curl up as easily. Too little (1/16 wide for example) and the metal will curl over top of the cutter, getting in the way of seeing your marked cut line. At about 1/4" wide, the strip coming off will roll off to the side, out of the way where it doesn't block your view. We will be demonstrating this on April 21st, but thought it may help you remember if I added the "why".
