Today I completed work on the right main spar extension. I drilled the holes with a combination of a 4" hole saw and a circle cutter (Sears Aviation Department). The circle cutter did a better job. Make sure the work is securely held down on the drill press with a block of woood underneath. Set the drill press on the lowest speed and then take it easy. Next, I completed the final drilling of the main spar, first to #30 and then #11. In photo 3, you can see masking tape on the spar in the middle of the table -- those are the holes not to drill out. I still have not drilled out the holes for the main spar caps -- still working on a solution to clamp the spar caps prior to drilling. 1/2" cleco's are not long enough. Photo three shows the left main spar ready for the main spar extensions to be located/drilled, and then final drilled. With a bit of luck, I'll be riveting late next week.
