Originally Posted by RandyAB
Nice pics. You can see that you put rivets in the skin along the rivet line in question while MED put them just between the backing plate and the angle. The instructions seem to point to both ways of doing it. I'm not finding them clear in this regard. Did you dimple or countersink the skin to accept the 426 3-4 rivets?
Thanks. More verbose explanation can be found in the links above each picture.
I dimpled all mating parts (skin, angle and backing plate). As long as you satisfy edge distance requirements, you'll probably have a more stout install if you rivet through the skin. Also, if you countersink the skin (assuming it's thick enough to accept a c/s), it may not be as strong a joining.
Sorry the Gretz instructions aren't clear. That is frustrating. FWIW, he states to "..drill the backing plate to skin holes through the backing plate and through the skin...". Then he says "Dimple the holes in the angle, backing plate and skin." So, with those two operations, it wouldn't make sense to dimple all those parts and
not fasten them all together with rivets. Further, Figures 2 and 3 in his instructions show the backplate dimpled. This implies the mating skin is dimpled (which you've match drilled to the backing plate), rather than c/s'd, too.
Hope you get it sorted out and can move on soon.