After we trimmed the aft root ribs per the dimensions on the plans and got them positioned with clamps it looked really good. (We were working on the left wing aft root rib.) When Dan match drilled through the bracket to the rib the hole at the edge of the rib the hole was really close to the edge, a little too close. Really fustrating. All the dimensions seemed right on. We think that perhaps the holes in the bracket were a 1/32″ off and the rib position was a 1/32″ off and the tilt of the root rib doesn’t help either. Perhaps all these little dimensions add up to the hole being off. Dan claculated the theoritical drawing distances and there is only an 1/8″ from the hole to the edge. Reviewing the plans there is no reason why the rib couldn’t be a little longer on both ends to give adequate edge distance. The rib just overlaps the attach brackets. So we discussed a doubler but decided to remake the ribs and trim them a little longer. One advantage of scratch building is that remaking parts is not imtimidating.
This was an interesting episode, if we had looked ahead in the plans we might have noticed the rib trim dimension was not critical and could be changed. However it would take a lot of time to research every part dimension to see what it’s function is.