Here's how to make a recessed box to hold your Piper or Cessna style ground power connector. This utilizes a hidden hinge and a Hartwell latch to make the door flush with the skin.
For my purposes, this design was based on a piper plug and I determined a 5"x5" hole would work best. So I used a drawing program to draw a 5" square with rounded corners, printed it out, cut it out and used it as a template. The picture below includes the template I used for the reinforcing ring that I mounted behind the hole
Next I made a box. I drew this box several times and made a paper mock-up before cutting aluminum. The theory on this box is that it is 6" square, and 2" deep. Only one side has a built in flange for mounting the box. The other sides are held on with angle stock. I bent this box the same way I made the trim tab. Clamp it between two pieces of wood where you want it bent, bend it with a piece of wood, then hit it along the bend with the flush rivet set on a low pressure setting. The are some directions on the template image for how to bend it. Paper is more forgiving than aluminum.
As I said, the box is held on with three pieces of angle stock and the one bent flange. You could use four pieces of angle, of course. In mine, the top and bottom pieces of angle are outside the box, while the one on the left is inside the box and sits on top of the hinge half. Why? It was to leave me with the room to allow the hinge to move freely in the box, and to keep a single line of rivets around the hole. The is a small piece of angle on the right side of the box, but it just serves as a catch for the Hartwell latch.
Then it came time to make the door and hidden hinge. I griped about the struggle I had getting the hinge right in another thread. Just go out and buy one. They're about $40 and from my perspective, after building three that didn't work, well worth it.
So, now the box is built and ready for prep and prime before final mounting. If you decide to build one, you have to think throughout the whole process about final assembly order, as some steps will prevent you from doing others.
This is not a cookie cutter set of instructions, so go one step at a time and measure everything two or three times.
Tip: Recessed Ground Power
Linear Mode
