RE: HOW TO ACHIEVE STRAIGHT LINES OVER THE EDGE?
I bought my HH trimmer from HH himself at the Westchester show some 13 years ago. Harry coxed me out of the audience to try it and the darned thing worked! With a new blade just hold the covering taut and the cut will start. Outside of the #11 blades, probably the best $10 I ever spent in the workshop.