Dimpling Nutplates

[David-aviator]

Originally Posted by Rick6a

I built two RV's and made everything removable with screws and nutplates. At no time did I ever feel a need to dimple any nutplate which in my mind is a kludgy way to do things. Production shops routinely use 1097's in aircraft production, why shouldn't you? An archive search will reveal much information on the subject. Here is one link with images that graphically demonstrates the possibilities using NAS1097AD3 rivets:
http://www.vansairforce.com/communit...ht=1097+rivets

I hate plate nuts.

The manufacturing tolerances are not precise at all. They are too tight, especially for #6 and #8 screws. I open them with a tap to make them useful. There's nothing more frustrating than stripping out a screw head half way in and having to spend time getting it out and starting over again. Sometimes Bolub or a spot of oil works but not always as some are simply too tight.

It never occurred to me to dimple the two attach holes. It would provide for a more precise install but it won't fix the issue of being under cut.

[Flyin'Bryan]

Originally Posted by RV6_flyer

Rick:

My RV-6 has been flying almost 15-years and has almost 2,600 hobbs hours on it. I, like you, did not waste my time or energy dimpling nutplates and I also used them everywhere something comes apart. Yes I agree that it is a kludgy way to do things by dimpling them.

I have not had any issue with any of the nutplates 15-years and 2,600 hours after installing them WITHOUT dimpling them.

After having gone through the process of dimpling all my trim tab servo cover nut plates, and then seeing how easy it was to use the 1097 rivets on the servo mounting bracket, I too am now in the camp of using the 1097s and countersinking as opposed to dimpling the nut plates. I too will most likely make many of the floor panels and other parts removeable, which means a lot of nut plates in my future. I think that using the 1097s is easier than having to dimple each rivet hole in the nut plate, and yes, that is my preference. To each their own in a free country.

Gary, I appreciate your statement about no problems after your long period of use. It further solidifies my decision to continue to use the 1097s. Now if I would only have read Rick's posts before I did the trim cover plate!

[tkatc]

Ok...I had never thought of dimpling a nut plate. While riveting the nut plates in place on my elevator trim attachment plate I noticed the nut plate did not mate perfectly with the end dimples in the material.

Since Vans instructions make no reference to countersinking or dimpling the nut plate....I just built on using the prescribed 426 rivets. the nut plates are completely serviceable and they are not "structural" in nature on this part but they do sit slightly proud on top of the 2 end dimples.

As mentioned in this post, this is an acceptable practice but I'd like to hear more opinions. I am not looking to debate 1097 rivets vs 426 but I'd like to know if dimpling or countersinking nut plates is required.

[N546RV]

Originally Posted by tkatc

Ok...I had never thought of dimpling a nut plate. While riveting the nut plates in place on my elevator trim attachment plate I noticed the nut plate did not mate perfectly with the end dimples in the material.

Since Vans instructions make no reference to countersinking or dimpling the nut plate....I just built on using the prescribed 426 rivets. the nut plates are completely serviceable and they are not "structural" in nature on this part but they do sit slightly proud on top of the 2 end dimples.

As mentioned in this post, this is an acceptable practice but I'd like to hear more opinions. I am not looking to debate 1097 rivets vs 426 but I'd like to know if dimpling or countersinking nut plates is required.

This is what I was taught in the Sportair class I took last year. When it came time to rivet a nutplate, I specifically asked the instructor (Ed McGowin, who to my knowledge has quite a few builds under his belt) how to dimple or countersink the nutplate. He told me neither was necessary.

Now I'm pretty curious to hear if this was bad advice.

[Walt]

Nutplates need to sit flush on the surface, just riveting them to dimpled holes is unacceptable. If the material is thick enough, lightly countersinking and using the 1097 rivets is fine, if the material is very thin then I would dimple both.

[BobbyLucas]

So glad I found this old thread. I was looking for a way, ANY WAY, out of dimpling any more nutplates, EVER! Lol. I have a Main Squeeze, which is freaking awesome, but I do not have a yoke that will accept the other half of the die set and I do not have a reduced diameter female die. I got through the 18 nutplates on my RV-12 VS by grinding off the front of my vise-grip dimpler female die and using that. However, it takes a huge amount of force and the vice-grips could not be released by hand so I had to use a channel lock pliers on the vice-grip release after every squeeze. And the nutplates get slightly bent in the process so then had to straighten them out - one of them snapped in half doing this. So yes, I agree dimpling nutplates is for the birds and I will not be spending ~$150 on a yoke and die to let me do it in the Main Squeeze. I also tried machine countersinking the nutplate, but I wasn't too thrilled about that either. Thanks to the VAF community I have ordered the "OOPS HOLE SAVER RIVET KIT" from Aircraft Spruce and hopefully will never look back!

[rocketman1988]

Originally Posted by David-aviator

I hate plate nuts.

The manufacturing tolerances are not precise at all. They are too tight, especially for #6 and #8 screws. I open them with a tap to make them useful. There's nothing more frustrating than stripping out a screw head half way in and having to spend time getting it out and starting over again. Sometimes Bolub or a spot of oil works but not always as some are simply too tight.

It never occurred to me to dimple the two attach holes. It would provide for a more precise install but it won't fix the issue of being under cut.

They are not undercut or necessarily out of tolerance. They are, by design, deformed to provide a vibration proof attachment, much like a nyloc nut.

That said, yes, some are just too tight. Running a tap through them will allow easy installation and removal but eliminates the locking ability...

Another thing to consider is if you are using a drill/driver to install or remove the screws. Try removing a screw with a drill then see how hot the screw is...it may surprise you...

[fl-mike]

Originally Posted by BobbyLucas

So glad I found this old thread. I was looking for a way, ANY WAY, out of dimpling any more nutplates, EVER! Lol. I have a Main Squeeze, which is freaking awesome, but I do not have a yoke that will accept the other half of the die set and I do not have a reduced diameter female die.

I'm confused. Do you only have no-hole yokes? A male/female dimple die set should fit into any standard yoke.
Regarding the reduced diameter female die, just grind one side of the die down to clear the center of the nutplate. I did just that 25 years ago and still use that die for all 3/32 dimples and nutplates.

[wirejock]

Originally Posted by fl-mike

I'm confused. Do you only have no-hole yokes? A male/female dimple die set should fit into any standard yoke.
Regarding the reduced diameter female die, just grind one side of the die down to clear the center of the nutplate. I did just that 25 years ago and still use that die for all 3/32 dimples and nutplates.

Same here. I process in batches. Check grip with a tap lubed with Boelube. Usually 2 turns leaves them perfect with enough grip to hold yet not so tight the screw galls.
Diimple the ears with the c-frame
Wash with lacquer thinner
Prime with NAPA 7220. I have a board with 40 nails. Makes it quick.
Yes, I know, not needed and total overkill, but I've found bad ones so tight the screw wouldn't go in or out and it was after they were installed. Now I just grab a pimed one and I know it's good.

[BobbyLucas]

Originally Posted by fl-mike

I'm confused. Do you only have no-hole yokes?

That is correct.