[briand]

I'm curious what others have done. The plate is a little thin for cutting.

Obviously if I dimple the plate I would also have to dimple the nut-plates.

 

[Brockster]

Dimple both like you said.

 

[TShort]

Get some of the NAS oops rivets - the ones with the -3 shafts and really tiny heads (don't have the number in front of me). Then you can make a couple turns with the deburring tool and you don't have to worry about the nutplate. Works great.

T.

 

[az_gila]

NAS 1097

Easy answer....

Countersink, but use the NAS 1097 reduced head 3/32 rivets. These will easily countersink into 0.025 material, and since you are attaching a nut plate, the only real strength you need is shear (twisting), so the small heads will be OK.

gil in Tucson

 

[JohnR]

I would agree with TShort and Gil, I have been using the NAS 1097. They work great and are quick and easy to install.

 

[RV7Factory]

Another vote for the NAS rivets!

If you don't have easy access to them and don't feel like ordering, I have plenty and will gladly throw some in the mail to you free of charge. Just PM me, but do it quick I leave for OSH early Sunday.

 

[chaskuss]

I'm curious what others have done. The plate is a little thin for cutting.

Obviously if I dimple the plate I would also have to dimple the nut-plates.

You can do this either way. One thing to consider is this. What happens if the C/S with the undersized rivet head fails (or that thin aluminum cracks around the rivet) some years down the road? The sender plate will come loose and ground out. Once that happens, your fuel gauge no longer works.
The only fix then will be to remove the tank & cut access holes to facilitate a repair. This possible prospect alone makes me vote for dimples and standard rivets.
The Germans have a saying, "The lazy man works hardest of all". FYI, you can buy nutplates with the rivet holes already dimpled. You just can't order them that way using Vans obsolete K1000 and K1100 numbering system. Here in the 21st century, a K1000-8 is called an MS21047-L08. To specify dimpled rivet holes, drop the L and add the letter K after the 08. So a standard #8 nutplate with dimpled rivet holes is an MS21047-08K. A triple dimpled #8 is MS21049-08K. Wicks carries these, so does B&B Aircraft Hardware.
Charlie Kuss

 

[Hawkeye7A]

Dimple the skin, use regular nutplates

On a number of locations on my -7A I had to install nutplates on .025" and .032" skin and I just dimpled the skin and riveted the nutplates directly to the dimpled crown. As an old-timer A&P once told me, "It's not the rivets that hold the nutplate to the sheet metal, it's the screw in the middle. The rivets are just there to keep it from turning while you install the screw." I measured one the first time and the gap between the skin and the nutplate is around .005-010". You may notice the center of the nutplate draw in very slightly to the aluminum skin but not enough to disturb the integrity of the fasteners. In my experience the flush heads seem to have a better fit into a dimple than a c'sink as well, as far as being at or very slightly below flush. Just my experience. Remember, you're building an RV, not a Rolex.

 

[briand]

Another vote for the NAS rivets!

If you don't have easy access to them and don't feel like ordering, I have plenty and will gladly throw some in the mail to you free of charge. Just PM me, but do it quick I leave for OSH early Sunday.

I have some OOPS rivets, thanks for the offer though .

I will have to think about this one. The first plate I did the dimple method BEFORE I came here and asked, I remembered doing it this way on the elev. trim cover brkt nutplates back while building the emp.. The ones I did tonight turned out kind of sloppy though.

 

[mlw450802]

I'm curious what others have done. The plate is a little thin for cutting.

Obviously if I dimple the plate I would also have to dimple the nut-plates.

The nut-plates are easy to dimple. Just take one of your female dimple dies and grind a little clearance relief on one side and dimple away.

-mike