Tank skin attach platenuts

[Jeff R]

OK, the good news is that my wing kit arrived today so the building is starting to get serious now.

While waiting for the kit to arrive, I have been studying the plans and thought I was prepared to begin with the tank skin platenuts. Well, maybe not. Looking at those beautiful, golden spars, I want to make sure I don't mess things up so I would like to ask for your all's advice before I get the microstop out.

Here is my plan. First, drill out the rivet holes to #40. I will drill out one of the holes, cleco a platenut to that hole and align the other hole, then drill it out. Next, with a #40 countersinking bit in the microstop, I will countersink those holes to accomodate an AN426AD3 rivet. I will then rivet the platenuts with my squeezer.

I was a bit confused for the next step. In the paper bag along with the platenuts in my kit, there were a bunch of #8 panhead screws, and I was wondering how the heck we are supposed to countersink those! Either I was given the wrong screws, or hidden at the bottom of the bag or somewhere else are the #8 CS screws. So, now that I have figured out I won't have to countersink for a pan head screw (!), once I have the platenuts riveted in, then I will do what the instructions say, which is to countersink the screw hole for a #8 countersink screw.

Hmm, writing it out like this (plus now assuming that CS screws and not panhead screws are used), it all seems pretty clear now. I have viewed most all of the RV-9 sites that Van's links to and I have read how people make jigs to do this, but it seems to me that what Van's recommends will be ok.

Thanks. This wing-building is going to be interesting!

[jim]

Jeff,

When you countersink the spar be careful not to run the drill too fast....you will get "chatter". I ended up switching to a cordless handheld drill for this, rather than the air drill, and ran it slower and the results were much better. I use the handheld cordless for most all of my countersinking now, with better results.

FWIW, and goodluck,

Jim

[G Swartley]

First Run the drill slow! I also used a battery drill for this.
Two I bought a "Single Flute Countersink Cutter" from Cleaveland tool. This made all the difference. NO CHATTER and nice clean holes.
Three I made a little jig cause the platenut holes are not round.

Just what worked for me

[Jeff R]

Thanks for the suggestion on using a cordless drill....I never would have considered that. They are heavy but, oh well, I need to start rebuilding my arm muscles again.

[alpinelakespilot2000]

Make sure you check the RVator article from about 1.5-2 years ago BEFORE you start. Van's changed their recommended procedure for determining the depth of the countersinks. (In short, don't use the dimpled test piece method b/c, according to Van's, people tend to countersink too deeply using this method). They have not, however, to the best of my knowledge, changed the builder's manual to reflect this new instruction (big surprise, right?!). If you do a search on this forum you should find an old thread that details the article. Good luck.

BTW, I too used a cordless drill, slow speed, and used the platenut to center the cutter per Van's plans. Worked just fine.

[GAHco]

My company and many others sell decent nut plate jigs that can save you a lot of time and trouble.

The countersinking would be done after the three basic holes are drilled.

Hint, always practice on like scrap stock and become an expert the less expensive way.

[Brantel]

You don't need a high dollar nutplate jig cause the holes are already pre-drilled. Even when they are not predrilled, a regular nutplate and a screw is all that is needed to drill them. The easiest way is to just rivet on the nutplate, then use your cage and countersink the spar just enough that the pilot of the cutter hits the nutplate at the very end of the job and you will get nice smooth countersinks that align well with your nutplates.

Some will state that this does not allow you to debur the backside of the hole. This is true but you can't really debur a knife edged hole anyway without making it too large.

You must have flat head screws somewhere or they sent you the wrong screws.

[GAHco]

Originally Posted by Brantel

You don't need a high dollar nutplate jig cause the holes are already pre-drilled. Even when they are not predrilled, a regular nutplate and a screw is all that is needed to drill them. The easiest way is to just rivet on the nutplate, then use your cage and countersink the spar just enough that the pilot of the cutter hits the nutplate at the very end of the job and you will get nice smooth countersinks that align well with your nutplates.

Some will state that this does not allow you to debur the backside of the hole. This is true but you can't really debur a knife edged hole anyway without making it too large.

You must have flat head screws somewhere or they sent you the wrong screws.

Sorry, I had no idea that even the nuplate holes were pre-punched in the newer structure peices.

I am a RV6 slow build with only pre-punched outer skins.

I like it that way, more challenging!

[Jeff R]

I found the right screws. Duh, they were in the paper sack that just hours earlier I had labeled "Fuel Tank Attachment H/W". I had been looking in the wrong bag of parts - it had the right platenuts, but had panhead screws.

With that issue settled, I commenced to drilling out and countersinking the attachment holes this evening, then riveting on the platenuts on one of the spars. So far, so good. I guess I will try countersinking the screw holes tomorrow to see how that goes.

As a sanity check, the TOP of the spar has the access platenuts, right? I am pretty sure I am reading the plans right, but it just stikes me odd that the access plates are on the upper surface. But maybe that is because I have only driven high-wing Cessnas.

Thanks for all the advice.

[Daver]

Well, my -9 wings have the inspection plates on the bottom.

Hope I did this right

Dave