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How to dimple nutplate holes on already installed firewall?

sritchie

Well Known Member
Hey all,

Technique question that I haven't been able to track down on the forums. I've laid out my firewall and drilled all primary holes for cable and wire passthroughs. I'm going to drill nutplate holes today, and I'm NOT looking forward to trying to dimple the nutplate holes in stainless steel using my pop rivet dimpler set with copper nails.

Any recommendations? For the holes near the top of the firewall I'm going to muscle the DRDT-2 up in the air and have a partner work the lever.

For the lower holes where I can't do this, I was thinking of using oops rivets and giving a tiny countersink to the steel with my deburring tool. This will PROBABLY work... but are there any "better" solutions out there?

Thanks all!
 
Yes, amazing! I just placed a cleaveland order for some glare shield material 10 minutes ago. I'll send them a note and add this piece to the order.

Thank you!
 
Definatley a nice looking tool- I'll have to make or buy one myself. I've been using the same idea but with a hammer instead of a rivet gun. Just make sure both sides are held perfectly straight! I made a couple ugly dents but at least they are in a spot thay doesn't show.

Cheers

Alex
 
Yep. Works great. We call it kamikaze dimpling for the reasons already mentioned. One of Tanya's least favorite things to do. No margin for error :).
 
Why

Why not use the pop rivet dimpler? You can get non copper nails. Works great I think.



Hey all,

Technique question that I haven't been able to track down on the forums. I've laid out my firewall and drilled all primary holes for cable and wire passthroughs. I'm going to drill nutplate holes today, and I'm NOT looking forward to trying to dimple the nutplate holes in stainless steel using my pop rivet dimpler set with copper nails.

Any recommendations? For the holes near the top of the firewall I'm going to muscle the DRDT-2 up in the air and have a partner work the lever.

For the lower holes where I can't do this, I was thinking of using oops rivets and giving a tiny countersink to the steel with my deburring tool. This will PROBABLY work... but are there any "better" solutions out there?

Thanks all!
 
Yes the firewall is stainless steel, but it is very malleable. You'll find that out if you push too hard when drilling a hole. Try the pop rivet dimple tool first, and use a steel finishing nail with it.
 
Just for reference, this is the same part that is in the bottom of the C-Frame. So many folks may already have one of these in the shop-

Not in MY Avery C-Frame. I just have the set holder. However, a machinist friend of mine made up one of these from an old spare set in a few minutes for me. To use effectively, both 'gunner' and bucker should use more force than when riveting and the guy on the trigger should be quick to prevent the sets from bouncing away from the hole. I've also had good luck (and more control), using the Avery upper set holder with a set and a dead blow hammer.

By the way, the easiest mod for the bucking bar is to drill a hole to accept a regular set, which can be put in an unpolished face of any steel bucking bar you have (in case someone thought you needed to machine a female set into your bucking bar to match the male set; TFeeney's post may not have made that clear).
 
Yes the firewall is stainless steel, but it is very malleable. You'll find that out if you push too hard when drilling a hole. Try the pop rivet dimple tool first, and use a steel finishing nail with it.

I did find that out when pushing too hard :)

Any tips on flattening out larger holes that have been bent inward slightly?
 
I did find that out when pushing too hard :)

Any tips on flattening out larger holes that have been bent inward slightly?

Back-riveting plate on the flush side of the firewall, and a flush set in the gun. Set the pressure low so you can control the gun.
 
I drilled and countersunk a piece of 1" square aluminium stock, which was used on the inside. Put a monel rivet in the hole and a few hits with the gun did a perfect countersink.

Drill and countersink additional holes in the aluminum (or steel) block for different size rivets.

Cost was zero since I already had the stock laying around.
 
Yes the firewall is stainless steel, but it is very malleable. You'll find that out if you push too hard when drilling a hole. Try the pop rivet dimple tool first, and use a steel finishing nail with it.

Mike's suggestion worked over 20 some years ago when I was building my RV-6. Used the same technique when I added a nutplate about a decade ago.
 
. . . I was thinking of using oops rivets and giving a tiny countersink to the steel with my deburring tool. This will PROBABLY work... but are there any "better" solutions out there?

I think this IS the best solution. It will definitely work.
 
Why not use the pop rivet dimpler? You can get non copper nails. Works great I think.

Yes the firewall is stainless steel, but it is very malleable. You'll find that out if you push too hard when drilling a hole. Try the pop rivet dimple tool first, and use a steel finishing nail with it.

Pop rivet dimpler will handle the firewall just fine.

Exactly what I was going to recommend. Buy a set, they are inexpensive and you will find that you will use them again.
 
Dimples

A steel CS rivet or a steel CS screw will do the job with appropriate CS hole in a bucking bar on the back side. In my homemade tool collection is a piece of aluminum bar 1/4" thick, 1/2" wide & 4" long. Riveted on either end are #6 & #8 nutplates behind holes that are a bit "over" countersunk. This tool goes on the backside instead of a bucking bar and will create acceptable dimples when screw gets tightened down. Works great if room is limited on the backside and won't stretch the metal like rivet gun and bucking bar can if overdone.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
 
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