Brief Description: Top center spar caps match drilled & reamed
Tonight I laid out the spar caps that go with the front web, clamped them securely and spot drilled them with the #30 bit. Next I set up my drill press with a #21 bit (for the AN-470-AD-5x rivets) to prepare for match drilling. On my first attempt at the center spar, I drilled the rivet hole through both spar caps where the dual control uprights were to attach using AN-3 bolts. This meant that I had a rivet shop head (from the rear web) nearly touching the back of my AN-3 dual control upright bolts. Not wanting that to happen again, I decided to only drill for the dual control uprights through the front spar caps. This meant that I had to be careful to match drill all holes except these (see image 2 below). After each matched hole was drilled to #21, I inserted a solid rivet (AN-470-AD-5x) to keep the two spar caps aligned. The last step was to use a D drill bit on the 1/4 bolt holes and a #13 (top spar cap only) for the 3/16th bolt for the dual control uprights. I then reamed each to their final sizes. Everything lines up perfectly. Now I will just duplicate the match drilling on the bottom spar caps tomorrow.
Matched up and drilled
Note the missing rivet. That is where I only drilled through the top spar cap.
