Fixing too large nut plate mounting hole

Tom023 · #1 05-29-2014, 02:27 PM

While drilling the nose rib to attach the nut plates that eventually will hold the stall warning assembly in place, I inadvertently drilled one nut plate attachement hole to #19 instead of the center hole for the #8 screw. I know this isn't too big a deal as I will have easy access to mount the assembly, and even in the case of replacment I will probably have access to both sides of the rib, but I would like to install the nut plate the best possible way. The way I see it I have a few opitons: 1. Don't dimple and just use a 3/32" rivet as it will just barely not go through the #19 hole. It will sit a little proud of the rib web, which perhaps I could file or shave down. Since the stall warner mounting plate would set against the slightly protuding rivet head, it would be ever so slightly out of position, which I would like to avoid. 2. Countersink a few thousands the back side of the stall warner mounting plate for the rivet head to nest into. 3. Just leave off the rivet and let the screw hold the nutplate on along with the other rivet.

Are there any tricks out there to solving this minor problem? Otherwise I'm leaning toward #2.

JonJay · #2 05-29-2014, 02:49 PM

If there is room, leave the existing holes and rotate the nut plate around the screw hole and re-drill.
Also they make many different types of nutplates; single leg two hole, two leg "V", etc... that might allow you to work around the existing holes or just use the one good one.

If none of that works, idea #2 doesn't sound too bad. I don't believe the stall warning device would be considered structural.

Tom023 · #3 05-29-2014, 02:52 PM

Both of those are better solutions than mine and will work, thanks! Sometimes the simplest solution is staring you right in the face and you can't see it. I need to open my eyes

JonJay · #4 05-29-2014, 03:20 PM

Quote:

Originally Posted by Tom023

Both of those are better solutions than mine and will work, thanks! Sometimes the simplest solution is staring you right in the face and you can't see it. I need to open my eyes

Your not the first. Now, and forever, you have that little piece of "I know how to fix that....."

airguy · #5 05-30-2014, 08:04 AM

Here's another option - abandon the oversized hole and use a one-sided nutplate. The correct-sized rivet hole will fit the pattern and you'll need to drill one more rivet hole.

I believe the correct part number would be MS21051-L08, 75 cents from Vans, you probably already have a bunch in a bag somewhere.

By the way - I found that I had a LOT more places in the build where this type of nutplate was advantageous than are called out in the drawings. You might want to order a couple dozen extras on your next Vans order.

Tom023 · #6 05-30-2014, 07:52 PM

Thanks guys, all fixed. I tried the one sided plate first but since it needed to be dimpled I thought the two dimples would be too close and interfere with one another. So I used the same nut plate rotated 90 degrees. Plenty of room. Funny when I created the issue I fixated on how to get a rivet in the same hole, while the easiest solution escaped me.