Nut plate with countersunk rivet holes

Post by **Mike Espinoza** » Fri Nov 30, 2012 3:16 pm

I am getting ready to order nut plates or anchor nuts (MS21047 two lug for 8-32 truss head machine screws) with countersunk riveting holes. They will be used to attach the left wing tip and in other various locations including the cover plate for the elevator trim motor. But, it does not seem possible that when I dimple the wing rib (.020"), that the dimple will fit inside the countersink of the nut plate. I am concerned that the nut plate will be raised by the dimples.

I would appreciate any any advice on how to proceed.

I found a supplier that has reasonable prices but there is a minimum order quantity so I cannot order just a few to try them out.

Post by **irishfield** » Fri Nov 30, 2012 4:04 pm

You could probably clamp them in a vice and counter sink them a little larger to accept the dimples. Another option would be to use clip nuts instead, that I was selling to the lads a few years back. I still have trays full of them at 50 cents each. I probably have the nytrol/fibre anchor nuts as well with the counter sink if you want to go that route... at a lot cheaper $ than any supplier sells them at these days.

Post by **Mike Espinoza** » Fri Nov 30, 2012 9:48 pm

Wayne,
Thank you for your reply. I will experiment as suggested to see if it works for me.

I intend to use clip nuts where possible but I understand that the outer left wing rib where the wing tip is attached faces in and a clip nut is not practical.

I will send you an e-mail to order the clip nuts.

Mike
R666

Post by **snowyriver** » Sat Dec 01, 2012 10:15 am

They're a litle spendy but Clickbond nutplates are fast and easy. One hole and you're done. Google them. Craig

Ken · Post by **Ken** » Sun Dec 02, 2012 3:48 am

I can recommend the clip nuts. Definitely a lot quicker to install and Wayne's have a very thin "clip" which makes them pretty much invisible from the exterior.

I've paid $5. per bag of 25 nutplates with dimpled rivet holes in the past at Oshkosh. They work well. I used a $5. puller that works with my pop rivet tools to make a nice small dimple in the aluminum for those rivets. Actually I think I reversed the female die and drilled an even smaller V into it for this. You can go use up a hundred or more of these nutplates surprisingly quick. I would think a decent vendor would mail you a sample for free.

For .032" and thicker I use standard nutplates and just countersink the aluminum slightly and use a REDUCED head solid rivet either squeezed with a welding clamp or whacked with a hammer.

If you already have standard nutplates I've tried drilling the nutplate to counter sink the rivet hole but that did not work very well for me.

Slightly better but not great was to drill a V into a block of steel with about a 7/32" bit, place the nutplate over the V, and use a counter sink or sharpenned rod to hammer a dimple into the nutplate. Then you have to straighten out the warped nutplate so again not really recommended.

Ken

>
>
> Re: Nut plate with countersunk rivet holes
>
> Unread postby irishfield » 30 Nov 2012, 20:04 You could probably
> clamp them in a vice and counter sink them a little larger to accept
> the dimples. Another option would be to use clip nuts instead, that I
> was selling to the lads a few years back. I still have trays full of
> them at 50 cents each. I probably have the nytrol/fibre anchor nuts
> as well with the counter sink if you want to go that route... at a
> lot cheaper $ than any supplier sells them at these days.

Post by **Mike Espinoza** » Sun Dec 02, 2012 12:26 pm

I will use Wayne's clip nuts to attach the tips to the rudder, elevators, and right wing tip.

But I am having trouble deciding on a nut plate. My application will be for attaching the left wing tip as clip nuts will not work. I also want to use these for access plates etc. I will be using an 8-32 truss head machine screw.

Would you recommend MS21047 with a fixed nut for MS21059 with a floating nut?

Ken, $5 for a bag of 25 nut plates is an excellent price. Do you have a part number? Most aircraft suppliers charge more than $1.00 each. The best price I found was $.19 from an automotive supplier but countersunk rivet holes are not available from that supplier. The next best price was over $.56 each for a fixed nut with countersunk rivet holes. It seems that aircraft suppliers automatically charge more for hardware. Wag Aero has a bag of 50 for $2.50 with an enclosed nut and little information.

I am thinking of using a solid rivet part number NAS1097AD3-4 to mount the nut plate. The small head will minimize the size of the dimple needed in the .020" wing rib and will fit well in the countersink of the nut plate rivet hole.

By the way, should I rivet the nut plate to the rib only before assembly and not the skin? That will be a challenge!

I know that I have a lot of questions and appreciate everyone's input. I am spending too much time researching this and would prefer to spend this time building my airplane.

Post by **irishfield** » Sun Dec 02, 2012 2:05 pm

My brain's not in full gear, but Ken, didn't we determine that my clip nuts could be used by sliding them between the flange and skin on the one wing... by clipping the little leading "ear" off the clip?

Terry R662 · Post by **Terry R662** » Sun Dec 02, 2012 11:40 pm

Hello Mike:

I installed mini nutplates on R662 for #6 screws. The screws and heads were just about the same size as a standard 1410 rivet for a pleasing visual. The nutplates/screws are spaced per the MAM manual rivet count specification. Probably could have got away with using half the number of screws on the rudder. Figured with the lead cantilevered on the leading edge of the elevators, a few extra wouldn't hurt (couple of ounces), so I made them all the same count. Just me I guess.

Also made a nutplate jig (see "Nutplate Jig.jpg") for the project which made drilling the ears relatively simple. Do have to admit that the installation took extra time to accomplish, however, I am going to do the same on the wing tips. Also, on the last nutplate location at the trailing edge, I had to resort to a pulled rivet because of tight quarters. I know that there is a solution to installing a solid rivet for tight quarters like this, but didn't want to fuss with it (as an option, I could have not installed a nutplate at that location, but that is just me).

You can also view the surgery that was accomplished to "lengthen" the tip leading edge and "squared up" the trailing edge of the fiberglass tip on photo "Tip Nutplates2.jpg".

Good luck whatever way you go with this.

Over-and-out . . .

Terry
R662

Post by **Mike Espinoza** » Mon Dec 03, 2012 11:19 am

Terry,
Thanks for the information and pictures. They are very helpful. The nut plates in the picture look like the rivet holes are dimpled. Do you know a supplier that sells them a reasonable price?

If not I may buy nut plate (MS21069) for $ .18 each and countersink them myself.

Mike
R666

Terry R662 · Post by **Terry R662** » Mon Dec 03, 2012 6:43 pm

Hello Mike:

Can't remember the suppliers name, but I think since I purchased from them, they have liquidated the business. Sorry.

The mini nutplates do have dimpled (#40) eyes. Purchased them several years ago for .15 US each. Part Number MS21071L06K using MS210426AD3-3 (AN426AD3-3) solid countersink rivets. Used these smaller nutplates because the distance between the MAM CS rivets at the tip of the tail skin was limiting.

If my memory serves me, the MAM specified spacing at the wing tip attach are farther apart, so “my big plan” is to use standard #6 floating nutplates with dimpled eyes if available. I have stainless phillips head screws now, but plan to use Allen head.

As with some builders on this list, I too have used Click-Bond nutplates. Mostly used in places where the area was tight and the nutplate would be accessible to grasp in case an adhesive bond failure occurred. These are very easy and quick installation and makes nice hardware. Expen$ive though.

Hope this helps.

Over-and-out . . .

Terry R662