Today was spent designing the ignition wire pass throughs. The stock plastic parts specified by Vans were not useable as they were designed for 5 mm wires and the ignition wires on my airplane are 8 mm. I was going to enlarge the holes on the specified parts but there was insufficient material to do so.
I considered 3D printing them but settled on machining aluminum parts with silicone grommets.
I used the Smithy milling machine to fabricate overlapping pieces by milling an 063 rabbit in the edge of an 1/8" piece of 6061 sheet.
The overlapping pieces were then clamped to a board and drilled to 9/16" for the grommets, using a unibit.
The mounting holes were then located, match drilled, deburred, and smoothed.