Page 8-49 Dimple countersunk the #40 nut plate attachment rivet holes. Dimple countersunk all of the #40 holes in the F-830-1 and F-831-1 seat floors. Dimple countersunk all of the #40 holes in the F-830B-1, C-1, D-1 E-1 and F-1 floor stiffeners primed all of the floor parts
