Started work today on the main spars. First chore is to countersink each of 120 holes for the fuel tank attachment screws - thats 30 holes on the top and 30 on the bottom of both spars. Then drill out and countersink the 240 holes to attach the platenuts. All in all today drilled and deburred 360 holes then countersunk each of those 360 holes as well, then riveted 240 rivets to hold the 120 platenuts on. Photo #1 shows the two tools I made to help me do this (learned from someone else's web site. At the top is a scrap piece of alum angle that I drilled the pattern for the platenuts in ( there were three different patterns and they were spaced at uneven intervals so had to essentially do them one at a time). At the bottom is a scrap piece of aluminum dimpled for #6 and #8 screws. The process goes as follows: In photo two, cleco on the pattern guide, then in photo #3 clamp on both ends and then remove the clecos (to give room for the countersink - see next entries photos.
