[chris mitchell]

Please could someone give me guidance on whether to dimple or countersink these two parts (trim access reinforcement and trim access coverplate, left elevator) and the associated nut plates. The screws are AN507-6R6. I'm guessing it should be dimpled because the metal doesn't look thick enough to countersink adequately, but if so what size dimple die should I use? #6? Sorry if this is dumb - being used to metric I struggle with some of these sizings/measurements!

Many thanks

Chris

 

[dan]

For the #6 screws, you can dimple the screw holes in the cover plate and dimple the holes in the reinforcement ring, and then use K1100-06 nutplates, which accommodate the dimple.

For the rivet holes attaching the nutplates to the reinforcement ring, you can just use NAS1097AD3-3.5 rivets (sometimes called "OOPS" rivets but not really OOPS rivets in the 3/32" shank diameter) and countersink the holes. The NAS1097 rivets have shallower heads than AN426 rivets, so c-sinking shouldn't "bottom out" or "knife edge" the material.

Or you could buy (or make) nutplates with dimpled rivet holes.

Pick your poison!

 

[chris mitchell]

OK, thanks, that makes sense now - I can easily make nutplates with dimpled rivet holes and I'll add the #6 dimple dies to my next Avery order.

Chris