Tonight I spent time redoing some wiring on the left wing. The main task was widening the holes in the ribs, allowing more wires to pass through for the heated pitot tube, plus some spare wires.
I picked up a 5 foot drill bit extension from Amazon for a few dollars. I installed my step drill bit which has a max size of 1/2 inch, my target hole size. The first problem was the fitting on the extension, which was significantly wider than 1/2 inch. I spent time grinding this down to just a hair under 1/2 inch.
With that done, I pulled out the wiring runs from the holes in question. I decided to unpin the molex connector for the main harness, because I’m going to replace this with a 12 circuit connector. This will allow me to terminate the pitot wires along with the lights etc. I found a wiring diagram another builder used, and will borrow that same layout. Anyway, I pulled out the wiring and then popped out the snap bushings, and started stepping up the holes.
I’m only going to up-size the system holes for the wiring runs, the two “spare” sets of holes will be occupied by my two pneumatic tubes for pitot and AOA. I could probably squeeze some more wires in with the tubes, but that’s not the plan.
The extension worked quite well, and I was able to quickly drill through all the ribs. The only issue came with the very last one, the most inboard that I needed to drill, because the drill extension was 6 inches too short. I was drilling from the inboard end, and had anticipated this, so I had another 12 inch extension. All was well until the smaller extension started slipping, and quickly reamed itself out. Luckily the step drill was almost through the hole, and some quick filing enlarged the hole enough for the snap bushing.
Some deburring, installing larger snap bushings, and then I re-ran the wiring.
This shouldn’t have taken long, but the tool modifications took longer than I had hoped. It was late by the time I finished, so that’s all I got done tonight.
