Brief Description: enlarge holes, debur and dimple main spar
I am so glad to finish this section. Main ribs which have support angles which get riveted to them were all originally drilled #40. They all had to be enlarged to #30 in place. Used the 12 inch bit to allow proper positioning of the drill. Don't want the drill chuck to gouge the main spar by accident. Then I removed all the main ribs and deburred the attach holes to the main spar and rear spar. The ribs attach to the main spar with pop rivets for most of the ribs except the outer two which get bucked rivets. Used the pop rivet dimple die to work around the tie down attachments which were crowding a couple of holes. PopRivet die worked perfectly. I also added a spacer piece of aluminum between the end of the tie down attachment and the main spar flange. Match drilled it to the existing holes and dimpled it for installation later. It takes up the tiny space left open between the skin and the tie down. Will seal it around the tie down hole with RTV from the inside. I am so glad to be finished dimpling the wing. This main spar was the last major dimple job. I also refit the wing walk doubler to be sure of my plan to countersink the doubler holes. The underlying 5 ribs will remain straight holes, no dimple or countersink. The top skin-dimpled; wing walk doubler-countersunk except for the forward 1st row of holes which will be dimpled holes that go behind(under) the main spar flange. Main spar flange between 1st 5 ribs gets dimpled to match the top row of the wing walk doubler dimples. Clear??
Dimpled main spar flange
Wing walk doubler fits under main spar flange and on top of ribs
