Finished up the right flap today. I'll start on the left next. Overall, the flaps are pretty straightforward and simple to construct. I used the same "ratchet strap" method to fasten them to the bench to make sure they are straight, and they turned out perfectly - no perceptible twist. I'm beginning to make more special tools and jigs to hold things in place and make accurate measurements. For the flaps, I jigged up a stand that holds the flap on its end for working on the hinges. I also made up a special tool to get a consistent, accurate measurement in getting the hinge bottom 3mm from the bottom edge - a couple of pieces of scrap masonite riveted together. Fairly clever if I do say so myself. I guess this just shows that I'm getting things figured out and using common sense to solve little problems as they present themselves. As an interesting side note, I ran out of A5 rivets on the very last pull of the flap hinge - a total fluke. Time to order more rivets and begin the left flap.