Brief Description: Skin overlap - filing for thickness
The overlapping corners of the main wing skins are being filed down in thickness at the leading edge of the skin... This is so the combined thickness of the ovelapping skins will be equal to the thickness of the skin immediately in front of it (the fuel tank skin = 0.032"). My brother, Mike, gave me a tip not to dimple these holes until the skin is thinned and also to only perform the thinning operation on the 'back' side of the skin... Thanks for the tip Mike; they came out great. To thin the skin corner, I laid the skin 'inside out' on the bench with the corner to be thinned near the front edge of the workbench. The skin was taped down to the bench in several places to keep it from shifting while filing. Next, a piece of sacraficial 'scrap' aluminum was also taped down adjacent to the corner to be thinned. This piece keeps the file teeth from 'catching' on the edge of the skin being thinned and also prevents the VERY EDGE of the skin from being excessively thinned. The results: A very smooth finished surface (this was a single-cut file) thinned to approximately 0.016" thick. After thinning the skin, the remaining dimples were dimpled using the C-frame dimpling tool. I estimate it took at least an hour or two for each corner since I didn't want to 'over thin' the corner and had to remove the skin from the workbench several times during the process. Note in photo #3 the pattern near the 45deg corners of the thinned skin - this was because the skin was 'edged' slightly before thinning the skin, thus the pattern seen here.
