Oops, countersunk (sort of) the wrong layer

[RV7Factory]

I made a boo-boo

A week or two ago while prepping my seat and baggage ribs, I decided that I while I was riveting the nutplates to the seat ribs, I would be a smart guy and rivet the nutplates onto the top flange of the F-727 baggage ribs as well. Mistake... The baggage floors get riveted to the ribs and nutplates through the same holes. Oops! And yes, I looked ahead in the plans but I still missed this.

Normally this would only be a minor problem but... I used NAS1097 rivets to attach the nutplates to the ribs so the underlying ribs now have a slight countersink to them.

Probably not a big deal, but does anybody have any recommendations as to the best way to fix this?

I thought about just leaving it alone and installing new rivets spaced between the nutplate to attach the floor to the ribs, but I thought about that after I had already drilled out 80% of the nutplate rivets. D'oh!

I guess I could dimple the rivet holes in the top of the rib, but since they are already countersunk the dimple gets a little thin around the edges. In addition I cold also put a few new rivets between the nutplates just to keep everything snug.

Anyway, I am all ears! Here are the holes I am talking about.

[cytoxin]

well you were using these i guess because your just holding a nut plate on, once the screw is in its not going anywhere.

if it were me i would drill out to the next size larger bit. (not rivet) this would remove the potential knife edge of the hole and dimple all three parts, then install them per plans. this is how i did mine except no machining as you did. i wouldnt worry about putting rivets between the nut plates. but that wouldnt hurt. YMMV.

[flion]

I agree, dimple all three. The rib will be sandwiched between platenut and floor. On my -6A I riveted the floor with the same spacing on all the ribs, modified where screw spacing dominated (spacing callouts are maximums; you can always go closer).

[Pmerems]

Brad,

If it were my project I would put some additional rivets between the nut plates. IE if the nutplate spacing is 3" I would add a 3/32 rivets at 3" spacing.

If you just riveted the nutplates as you have already prepared and didn't attach the floor skin in this area, the floor rib will flex and bow causing some issues with the screw hole alignment. This could be a bit of a pain when installing the center cover. If you install the rivets in between the nutplates this will solve this issue.

Not a big problem. If this is your worst problem on the project you should be thankful.

[Norman CYYJ]

Don't worry about it. Remove the nutplates and install the floors as required. The rivets will have plenty of material to hold on to and the rib will be sandwiched between the floor and the nutplate. The amount of material that you removed for the NAS rivets will not be a concern to the strength of the floor installation. Extra rivets won't be required. Also the screws are holding things together which hold down the cover plate.

[alpinelakespilot2000]

Brad-
All of (the many of) us who have done the Van's-approved mod of screwing our baggage floors down (rather than riveting) end up with exactly your same situation. We rivet the platenuts only to the ribs and we don't add any extra rivets anywhere else. I don't see any reason to drill out any of your platenuts just so that you can rivet the platenuts to the baggage floor as well.
My .02.

[RV7Factory]

Thanks guys. I didn't think this was big issue, but it's good to know I have some options. I appreciate the help!!!