Brief Description: Cutting and shaping the doublers, part 1
I'm actually using two doublers. The bottom doubler shelf is 0.04", and has the 3/4" shelf that extends into the access hole: The panel will screw to this doubler. Because its inner hole is smaller, I drilled 1" diameter corner holes into its inner hole corners using a step-drill (images 2 and 2).
In addition, I'll use another same-sized sandwich doubler in 0.032" sheet. This one sandwiches between the top skin and the bottom doubler shelf, which will allow room for a water gasket between the access panel and the bottom shelf doubler. The sandwich doubler's inner holes must match the access holes on the top skin and the access panels themselves, so I drilled 2" corner holes (image 3).
