Brief Description: Pilot drilling parts for wing spar
I finished the main de-burring of the spar and then moved on to drilling pilot holes and clecoing different parts/assemblies to the spar.
First, I pilot drilled the lower angle (SNX-W11-01) to the spar. Unfortunately, I already up-drilled the holes on the spar where this angle attaches. I should have waited to up-drill these holes until I was ready to pilot drill the angle so that I could use the smallest holes as pilot guide holes. Since these holes are now at the #21 drill size, I needed to be careful in making sure the angle was clamped securely while I was drilling. I first made a depression in the angle at each hole location by using the large holes as pilot holes to mark where the holes go. I then used the center of the depression as a pilot to help guide the #40 drill through the angle. Once this was done, it was easy to continue up-drilling both the #30 and #21 drill sizes.
Next I positioned and pilot drilled the end wing (SNX-W11-02) and root wing (SNX-W11-06) attach assemblies. These assemblies need to be precisely aligned with the pilot holes that the wing attach pins will ultimately go through. To help with this alignment, I purchased a #40 drill bushing that has an outside diameter of 3/16". This allowed me to align the 3/16" hole in the blocks on each attach assembly perfectly with the 1/8" hole in the spar web. Too bad I didn't think to do this with the Left main wing spar.
Drill bushing used to align attach assembly with pilot hole in spar web.
Drill bushing in attach block, ready to align the holes.
