Brief Description: Countersinking and Edge Finishing
Carefully examine the plan before working on the lower portion of the rear spar, VS-803PP and the spar doubler, VS-808PP as the lower rivets are set from the inboard side using flush rivets. Make sure to dimple VS-803PP and machine countersink VS-808PP making sure to machine the back side of the part.
After the machined countersinking is complete, all edges of VS-808PP and the lightening holes get finished. I used a combination of the Scotch Brite wheel, Scotch Brite pad, and various files to perform to work the edges and inside the holes.