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How to install nutplates ?

herve-RV7

Active Member
Sorry for this strange question ( :confused: ), but I'm not sure to have the right technics for installing the nutplates, especially on thin sheets as in the interior of the fuselage. Untill now, I have carefully countersunked the aluminium sheet, but when it is very thin, it is difficult to have the rivet really flush, and holding seriously the nutplate. Is it possible to dimple the aluminium sheet, and countersink the nutplate ? If yes, how to do that ? Thanks in advance for sharing your experience on this issue.
 
Dimple both... I've done this on some of my nutplates and although it's a tight squeeze, the small diameter dimple die fits fine in there...
 
I think there are a couple options.
Some people dimple the thin aluminum then dimple the nutplates or buy nutplates that are designed to accept the dimple.

The other option is to buy the small head rivets - they are still 3/32 diameter but have a very small head so the countersink can be made with a few turns of the deburring tool. I can't seem to find the part number ... I have some in the shop but am not there right now - maybe someone else will chip in with the part number.

T.
 
herve-RV7 said:
Sorry for this strange question ( :confused: ), but I'm not sure to have the right technics for installing the nutplates, especially on thin sheets as in the interior of the fuselage. Untill now, I have carefully countersunked the aluminium sheet, but when it is very thin, it is difficult to have the rivet really flush, and holding seriously the nutplate. Is it possible to dimple the aluminium sheet, and countersink the nutplate ? If yes, how to do that ? Thanks in advance for sharing your experience on this issue.
Herve,
I have an old set of dimple dies with a relief ground into the side of the female die for clearance of the nutplate. Then I just squeeze a dimple into the mounting arms of the nutplate.
That seems to help it nest much more closely to the dimpled aluminum sheet.

-mike
 
Don't call me "Oops"

herve-RV7 said:
Sorry for this strange question ( :confused: ), but I'm not sure to have the right technics for installing the nutplates, especially on thin sheets as in the interior of the fuselage. Untill now, I have carefully countersunked the aluminium sheet, but when it is very thin, it is difficult to have the rivet really flush, and holding seriously the nutplate. Is it possible to dimple the aluminium sheet, and countersink the nutplate ? If yes, how to do that ? Thanks in advance for sharing your experience on this issue.
Not a strange question at all considering Van and Duckworks that I know of off the top of my head ship optional accessory hardware kits stocked with AN426AD3 rivets and called out to be used in material as thin as .025. This is NOT good practice. To add to the confusion, Van characterizes NAS1097AD4's as "Oops" rivets, so most builders tend to think that because of its smaller head size, the only time they are used is to fill in an oversize #40 dimpled skin hole with a 1/8" rivet so nobody can tell the difference. NAS1097 rivets are way more than that.

As a matter of routine practice, I almost always use NAS1097AD3 rivets when installing nutplates regardless of material thickness. These rivets are available in almost as many lengths as regular AN426 rivets.

Van's stocks NAS1097AD3 rivets but you have to search them out on "The List."

You will likely find the NAS1097AD3-3.5 will be the most commonly used length. ;)
 
What Rick said. http://www.vansaircraft.com/public/parts.txt

NAS1097AD3-3 RIVETS (LB) $33.00
NAS1097AD3-3.5 RIVETS (LB) $39.00
NAS1097AD3-4 RIVETS (LB) $30.00
NAS1097AD3-6 RIVETS (LB) $26.95
NAS1097AD4-3.5 OOPS RIVETS (LB) $22.71
NAS1097AD4-4 OOPS RIVETS (LB) $19.94
NAS1097AD4-5 OOPS RIVETS (LB) $19.26
NAS1097AD4-6 OOPS RIVETS (LB) $20.88

It's the 3- ones that you want for nutplates. 1/4 pound should last a lifetime.
 
Agreed on the NAS. Highly recommended! I did the first half of my project dimpling the skin and nutplates with AN426 rivets. Then I switched to the NAS rivets and it is so much faster and (usually) a neater installation. All you need to do is turn your deburring bit a few times in the skin hole that you want countersunk and your done. Remember, all the rivets are for is to hold the platenut. Also agreed that the dash 3 rivets are really the only length you'll need, though I have used dash 3.5's occasionally until I learned that they were too long for most applications.
 
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I dimple the aluminum skin and rivet the nutplate on. It sits on top of the dimples, so it is slightly off the skin where the screw comes thru but who cares. I think this is the simplest and fastest method... and I don't see a downside.

Karl
 
Countersinking

I'll jump on the bandwagon for NAS1097's too. Good stuff.

With small heads they need little countersinking. I found that by placing the #40 countersink bit in my deburring handle, it takes about 6 turns with light pressure to c'sink for the platenut rivets.
 
Is this wrong?

I dimple the aluminum skin and rivet the nutplate on. It sits on top of the dimples, so it is slightly off the skin where the screw comes thru but who cares. I think this is the simplest and fastest method... and I don't see a downside.

Karl

I saw another site with similar discussion. The response from one person was, "if he was the inspector, he would not sign off on this." I guess my big question is why? Is it not an acceptable practice?
 
When the screw or bolt that screws into the nutplate is tightened, the clamp up will try to pull the nutplate to the skin it is mounted to. The body of the nutplate must sit flush on the inside of the skin it is mounted to or the skin will end up stressed when the fastener is tightened. If the nutplate body doesn’t end up flush it can wiggle around inducing cracking at the rivet holes.

The NAS1097 rivets will work, as will dimpling the nutplate flanges. Of course you could always buy the nutplates designed for dimpled skins too.
 
I saw another site with similar discussion. The response from one person was, "if he was the inspector, he would not sign off on this." I guess my big question is why? Is it not an acceptable practice?

Is not acceptable because it creates a gap between the plate and the skin. The whole thing has to distort to handle the loads of the fastener. Bad.

I'll jump on the bandwagon for NAS1097's too. Good stuff.

With small heads they need little countersinking. I found that by placing the #40 countersink bit in my deburring handle, it takes about 6 turns with light pressure to c'sink for the platenut rivets.

This is the way to do it - with NAS1097 rivets. After learning, all mine are installed this way - Vans (now) has this explained in the Section 5.

No dimples needed, even in .025" thick material.
 
Symantics

If the skin and nutplate have the rivet holes dimpled, i think there is no problem. The rivets just hold the nutplate until the screw goes in. But if the skin is dimpled but the nutplate is not, i think this is a problem because the nutplate wont sit against the skin when the screw is tightened. JMHO
 
Nutplate install.

In rare circumstances I’ll use a dimpled nutplate on structure or skin with dimpled holes, but otherwise it’s all NAS1097’s. 7 turns with a hand cranked countersink with about 1 lb of pressure works out just right. I use a hand squeezer whenever possible and before squeezing i put a short (1/8”) length of windshield washer hose over the rivet tail for the first squeeze. This clamps all the pieces together before the rivet swells. Hose gets removed for the final squeeze. Use the hose trick with the rivet gun as well.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
 
The NAS1097 rivets will work, as will dimpling the nutplate flanges. Of course you could always buy the nutplates designed for dimpled skins too.

There are nut plates designed for dimpled skins? Does anybody have a part number I can look into? I've always used the previous two methods and prefer the NAS1097 rivets.
 
There are nut plates designed for dimpled skins? Does anybody have a part number I can look into? I've always used the previous two methods and prefer the NAS1097 rivets.

Yup, go to Aircraft Spruce Anchor Nuts, and then scroll to the bottom and look for Dimpled Rivet Holes. But as others have mentioned, it's a fairly simple task to just dimple the nut plate rivet holes in the shop.

While I appreciate a good dialog on the finer points of plate nut rivet hole dimpling, especially if I have a hot of cup of coffee in the process, it's really not that critical on the rivet type hold them...the rivets on the plate nut should not be considered a structural component, but rather have the purpose of holding the nut while you install the fastener. Although there are some cases where a designer could use the plate nut for retaining a backing plate or joining sheets (not something I'd recommend though) - even then, assuming the fastener is properly torqued, the rivets could be removed and not affect the holding capacity of the fastener.

There should be no problem with using CCR-264SS-3-2 blind rivets for thin metal, or hard to reach applications, with their only downside being cost when compared to a solid rivet.
 
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Ah, I see them there now, thanks. For double or triple the price, I'll dimple the nutplates myself. :D

On the other hand, maybe I should open a business of dimpling nutplates. I'm sure I can squeeze out several hundred per hour (pun intended).
 
Is there a source other than vans for the “oops” kits for the 1097 rivets? Can’t see how to order them via Vans and I’d prefer not to buy a whole kit.
 
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