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APilot4Fun

Member
After fitting the seat floors in the fuselage and match drilling to the seat ribs, I've come to installing the nut plates for the floor. Not finding a technique for doing this, I secured a nut plate upside down on the top of the seat rib over the hole with a Cleco from the underside and match drilled for the rivet locations. Seemed reasonable. However the Cleco holding the threaded part of the nut plate didn't hold the center of the hole. Once the countersunk rivets were installed holding the nutplate in its almost correct position, I found the screws were a fight to go in due to the slight misalignment of hole centers and it seems that I will need to open the affected holes slightly to let the screws go in without resistance.
I know what I did was the wrong technoque, but how should it have gone and will the slight opening on a few floor panel holes cause any trouble in the future?

-Craig
 
You should have used a bolt instead of a cleco to hold the nut plate. Use a short bolt with a washer stack to avoid having to go into the locking part of the nut. After you have the rivet holes drilled, enlarge the bolt hole. It's not doing anything once you get the nut plate installed.
 
A minor variation to the above process is to use a common machine nut on the screw/bolt that you use to temporaily hold the platenut (upside down from the intended final position as a template) while drilling the rivet holes.

Adjust the nut such that the screw/bolt only catches the first few platenut threads (before the locking area of the platenut). This allows quick insertion and finger tightening to lock the platenut in prep for drilling. Drill one of the holes, insert a cleco and then drill the other hole. Can be done very quickly and is very accurate.

Also, you will probably want to use some corner and one legged platenuts for problem areas.
 
The really easy thing to do is use a nut-plate jig. With so many nutplates to position, this is really the way to go.
 
APilot4Fun said:
I know what I did was the wrong technoque, but how should it have gone and will the slight opening on a few floor panel holes cause any trouble in the future?

-Craig
Click to expand...
There's nothing really "wrong" with this method. I've used it for a million (OK, not quite that many) platenuts. Perhaps if your #30 clecos are slightly undersized it might be problematic, but I've only had problems with it a couple times. I'm one of those who used them on the baggage floors as well, so that's about 55 more than most people have. Like Jim suggested, if you really want to make sure this never happens again, get a jig. I'm just on too much of a budget, or just plain cheap! :rolleyes: The screw method will work great too, it just adds some time to the installation process and, again, I've had no real problems using the cleco method. Good luck, though, as you find your way.
 
I took a nut plate and tapped it out, also ran a screw/bolt through a die so that I could easily run the screw/bolt down quickly while working. The obviously stated nut plate jig works well also. I had a few of the nut plates come out like the original poster and I did come to being ok with drilling out the screw/bolt hole slightly larger than perfect, no one will be any the wiser as you wont be able to see this after the finished product, definately not during a low approach, it will be our little secret.
Funny the timing of this post as I was out looking at my floor area and wondering about inspections and if anyone pulls the floor to have a look? especially the guys who riveted the floors in? I currently have not put in nut plates for my flooring (build it per the plans mantra you know) but I am second guessing the riveted in floor again.
 
I riveted my floors down in 1992 as per the plans. Took them up last year to install steps. Everything looked just like it did in 1992. Riveted them back down again.
 
Well that boosted my feel good factor on going with the plans then, thanks mel.

Onward and upward.....someday
 
I should have used a screw

Thanks for all the replies.
The screw seemed like it was the right tool to use but I just didn't think of a basic machine nut to spin down and keep things steady. The Cleco just seemed right to me but it just didn't work out as planned for me. I've only installed 6 nut plates so the other holes will benefit from this experience.
I've also discovered the need for alternate nutplates. Some of the locations are too tight to work in and I've found the need for the nutplates with the two rivets on the same side. It's funny the plans don't seem to call for these in areas that seem obvious for their use. But then again, the plans have left me scratching my head a time or two before this.

Thanks again!
-Craig
 
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