Brief Description: Drill the holes in the wing root doubler to final
1. Moved the drill press to the end of the work bench so that I could keep the drill bits and reamers normal to the spar caps.
2. Set up the Rockler roller supports to keep the spar level on the drill press table. I had to adjust the support height when changing from drill bits to the reamers which were longer. Also, a flat support surface would have worked better than the rollers, because the it was difficult to position the spar when either of the rollers was under the spar rivets. Something like a 3-in by 15-in piece of wood covered by a slippery piece of 1/8-in thick polyethylene might work better. See Fig. 1.
3. I drilled the top spar cap bolt holes to 15/64-in and then reamed with a 0.247-in reamer. That gave a very nice tight bolt fit, requiring light tapping to get the bolts into the holes. I left a couple of bolts in place secured by hardware store nuts, since I do not have any 0.25-in clecos. See Fig. 2.
4. Next I drilled out the holes for the wing attach bolts in steps to size N (0.302-in) and then reamed to 0.3125-in. Unlike my other reamers, my 0.3125 reamer is not piloted. When I tried the Zenair supplied NAS bolts in the 1st two reamed holes, the bolts were a bit loose. My calipers indicated that the bolt diameter was 0.3085-in, which would account for the looseness. I decided to order a 0.309-in piloted reamer from Brown Tool to use on the remainder of the wing attach bolts. I will not drill the remainder of the bolts until I get the new reamer.
5. To support the spar on the drill press table I built a jig from scrap 1x2's and plywood. The 1/2's are screwed to the plywood separated to allow the jig to support the spar caps between AN4 bolts through the doubler. The jig is shown in Fig. 3.
