Centered and squared Attachment over spar, doubler and shim. Clamped in place then back-drilled the upper and lower center line holes. Removed attachment, located remaining 23 holes on bottom side (facing forward in aircraft) using scale and rivet spacing tool. Dimpled and drilled 23 holes from this side. Clecod attachment using the two centerline holes then drilled 23 holes through shim, doulbers and spar from top side.
Trimmed upper doubler trailing edge to match the spar flange. Tweaked the upper and lower spar flange angles along length of part to obtain consistent 85 and 95 degrees respectively.
