Since the front spar has already been drilled, the aft spar drilling will define incidence between the two wings as well as sweep forward and aft. A digital level will be used to measure incidence. The Avipro manual suggests using a wood block between the spars, but I couldn't find a completely flat one. So I used a 32 inch length of 1 inch angle iron, which I secured to the level using a pair of countersunk screws. I put a bit of teflon tape on both ends so as to not mar the finish. A measuring tape is used to measure the diagonal length from the tail, so as to determine sweep. I made a homemade .025 inch aluminum "fender" washer to keep the tape attached to the tail bolt. I wanted to use the Avipro drill guide, but Mark Goldberg was already on his way to Oshkosh, so he couldn't ship it. Since I didn't want to wait until he came back and shipped it to me, I went ahead and fabricated a successor to the Avipro, which uses a set screw to lock the reversed drill bit in place, so that two people aren't needed to use the guide.
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