When positioning the hinge for drilling into the skin, I found that the hinge extended into the counterbalance cutout by about 1/32" (image 2). I had made the cut as specified, but the counterbalance assy would not fit. I centered the assy between the centerlines for the ribs, and marked the cutout width based on the assembled counterbalance. The cutout is a close fit, so the excess hinge was trimmed back. Looking into the dimensions, I found that the stack up of the counterbalance parts is 1.531" and the cutout dimension is specified as 1.469". The difference is about 1/16" total.
Finished installing the ribs and hinge, updrilled all, disassembled and deburred.
Confirmed all the internal structure was satisfactory , reassembled W04-01R and it is ready to rivet.
