Drilled 1-1/8 x 1-3/8" holes in left and right spars. Deburred right spar.
Positioned doubler and attach plate to match the 1-1/8 x 1-3/8 holes on the right spar. Drilled, cleco'd, and up-drilled to #30. Positioned aft rib into position for use as a template to drill rib attach holes into the rear spar in the vicinity of the doubler and attach plate.
Drilled radius blocks to 3/16. Drilled upper/lower root rib attach bracket end holes to 3/16 to accomodate AN3-7A bolts.
Notes: Having the 12" drill allowed some flex when drilling the rib attachment holes. Nice to have. Also had to radius the doubler plates. Since these are part of the supplied parts, initial thought was that they were ready to go. Had to go back to the plans to see that the builder must radius the one edge where it fits into the bottom curved part of the spar channel.
Positioned the doubler; drilled, cleco'd and up-drilled to #30. Positioned aft rib to correctly space the rib mounting holes where they overlap the doubler.