Undimple?

Hello all,

Not sure if this has been asked before.
I dimpled all the holes in the flanges of the Leading Edge ribs.
When I was countersinking the W-423 joint plate I realized my mistake: the LE skin should be dimpled, the joint plate should be countersunk, and the inboardmost LE rib should be left as is.

My question is, if I "undimple" the holes in the inboardmost LE rib using the flat die set, will it present any structural weakness when under normal stress?
You picture this: the whole rib flange going from flat, to dimple, and back to flat.

Only one rib presents this issue (left wing).

What say you?

undimple

Miguel
Try it on some scrap. The other problem is deformation of the part when you un-dimple.
I'm sure some one will reply on the structural issue but I would ask Vans Tech Support so you have something documented for you builder log.
I know there are other parts they recommend un-dimpling because builders make that error often. Maybe this is one of them.

Just dimple

I am confused. According to the building manual for RV-7 (page 7-9), the W-423 splice plate should be dimpled:

"Dimple the screw holes and the rivet holes for the rib and platenut attachment. The holes for attaching the to the rib and skin can be slightly touched up (like the rear spar) to gain better fit between the skin, the splice plate, and the rib"

So, unless you choose to use oops rivets for the platenuts (I did), every single hole in W-423 is dimpled.

In some 2024 aluminum scrap, drill a #40 hole, dimple it, then reverse dimple it. Then dimple it the first way again and the whole dimple will usually break off in your die. Flattening a dimple certainly weakens the part. I don't know of the specific application, but don't flatten it if you can dimple the mating part to match instead if countersinking.

nilberg said:

I am confused. According to the building manual for RV-7 (page 7-9), the W-423 splice plate should be dimpled:

"Dimple the screw holes and the rivet holes for the rib and platenut attachment. The holes for attaching the to the rib and skin can be slightly touched up (like the rear spar) to gain better fit between the skin, the splice plate, and the rib"

So, unless you choose to use oops rivets for the platenuts (I did), every single hole in W-423 is dimpled.

Click to expand...

Yep.. I got ahead of myself and made a ton of scrap and practice pieces..
Calling in for some replacement parts.