[mikemalone]

Anyone know the minimum acceptable thickness of material to countersink for a -4 rivet. Trying to correct a mistake whereby I dimpled the F-770 skin where the plans call for AN470-4 rivets. The understructure, the material to be countersunk, is the F-704H centre section side plate. I believe the side plates are 1/16" thick. Thanks.

 

[Auburntsts]

According to Section 5, "for AD4 rivets, .050 is the minimum thickness that may be countersunk."

 

[-goose]

You would be ok to tap the dimple flat again. You won't get it perfectly flat as the metal is stretched, so it will want to dome slightly - but you'll get it very close and once you've set the rivet it will be fine.