First thing was to drill out the rear bottom hole in the spar to the correct 5/16". Next was to prepare the eight doublers for installation. I had to drill out, using a #40 bit, the three rivet holes and the 5/16" bolt holes in each doubler.
Next, using the 5/16" bolt to align the top doubler with the spar, I clamped it in place and used the #40 hole in the doubler as a guide to drill through the spar. Once drilled, I cleco'd it in place which clamped the doubler while I drilled the remaining two holes in the spar. I then placed the second doubler on the inside of the spar aligning it with the bolt and the clecos previously installed. Once both doublers were in place, I used a #30 bit and match drilled the rivet holes.
Once all the doublers were drilled out, deburred, sanded and cleaned, I mixed just enough Hysol to do two of the doublers at a time since they are top and bottom of the same 5/16" hole. I gooped the Hysol on the mating surfaces of the doublers a put them in place using a #30 cleco in the middle rivet hole to secure them for riveting.
I repeated the process for the remaining doublers and left them to cure overnight.
