I got a little overzealous filing one of the frames so I decided I needed to fabricate another so here I can show some images of the Pneumatic Nibbler. Image 1 is a picture of me using the nibbler. What is hard to see is that I have previously used my hole saw with my drill press to cut out the four inside corners. They provide a place for me to "plunge" my nibbler into the inside of the frame and the desired inside radius for the frame. I have the frame blank held down to the work bench with a straight edge board that hleps me cut a straight line. Image 2 shows the frame after I've cut out the center and Image 3 shows the "bites" or "nibbles" that the pneumatic nibbler cuts. Let me also say (if I haven't already) that these little crescent shapes pour out of the nibbler and bounce all over the place. I have to spend a lot of time searching the garage floor to make sure I vacuum them all up.
Using a Pneumatic Nibbler to Cut the Center Out of a Landing Light Frame
How the Frame Looks with the Center Section "Nibbled" Out
Samples of the "Bites" the Pneumatic Nibbler Takes Out of the Aluminum Sheets