Rear Spar Work

Spent several hours work with my friend Ross on the rear spar. Riveted in one of the doublers, and worked on the one of the wing rib attachment assemblies. Discovered a possible plans error on page W15, it calls for a 1 inch screw, but that seems two short as it does not allow for 1 1/2 threads to be exposed above the nut. Looks like it needs 1 1/8 inch screw. Will post on build forum and contact Sonex about it.