Rivet Nuts

[Randy's]

Based on suggestions from other builders, I will be using rivet nuts in certain situations; to make the trans tunnel removable is one instance. I ordered aluminum rivet nuts from McMaster Carr. My issue/question has to do with the screws. I can't seem to find screws that are made of aluminum in the thread size I intend to use; 6-32. There are plenty of stainless steel, brass, zinc, etc. I've read that using mixed metals can cause "galvanic corrosion" yet I've read on the forum where many used stainless screws on their removable trans cover so I'm confused. Should I mix metals i.e. stainless and aluminum? If not, is there another option instead of aluminum screws that I can use with aluminum panels?

[GoDadGo]

Randy,

I used 10X24 aluminum rivet nuts for my dash, all access hatches, and top of transmission tunnel.
Stainless button head allen screws with a 1/8" heads make it easy to use one tool to remove everything.

https://youtu.be/IGYtX-3p7xk

Just pick the size and material that you want and you'll be fine because they aren't going to be submerged in H2O, I hope.
Good Luck & Have A Great Build!

Steve

[Avalanche325]

You do NOT want to use aluminum screws. Yes, dissimilar metals cause galvanic corrosion. But in the real world, this is not a situation where it will be an issue.

I like removable elephant ears, drivers footbox access panel. I did my nose aluminum which came in handy on a radiator change. Things that make the car more serviceable.

Think of what you need to do to the top of a transmission.......nothing besides maybe get to the shifter (not yet in 20K miles), which you can do without taking the cover off. There is nothing else up there. You can do anything else from underneath.

[jrcuz]

If you are concerned about galvanic corrosion maybe use a VERY light amount of anti seize.
JR

[GoDadGo]

I like removable elephant ears.


Great Idea!

[John T]

I've never had the occasion to use rib nuts. I am considering them now. My question is--is there a tool that I need to use to install them?

[GoDadGo]

I've never had the occasion to use rib nuts. I am considering them now. My question is--is there a tool that I need to use to install them?

Da-Tool:
https://www.rivetsonline.com/kits-tool-kits-for-rivet-nuts-and-blind-rivets/rivet-nut-kits-with-tools#1

Wide Lip Ribbed Rivet Nuts:
https://www.rivetsonline.com/steel-rivet-nuts-threaded-inserts/ribbed-l-series-steel-rivet-nuts#1
https://www.rivetsonline.com/aluminum-rivet-nuts-threaded-inserts/ribbed-l-series-aluminum-rivet-nuts#1
https://www.rivetsonline.com/stainless-steel-rivet-nuts-threaded-inserts/ribbed-l-series#1

Not sure what a Rib-Nut is, but a lot of use install rivet nuts in places where we can't easily install a nut on the back side of a screw, allen head screw or conventional bolt.

I can yank the dash, stereo, fuel sending units, master cylinders and clutch slave cylinder, top of transmission tunnel all using a 1/8" allen wrench.

[John T]

Thanks, The link shows a tool that looks like the one I use for pop rivets. Is it the same?

[John T]

I see the confusion. My typing leaves something to be desired. Riv nuts or rivet nuts is what I was referring to.

[FlyingCobra]

All the aircraft I've worked on use stainless steel screws on the rivnuts (of which we have thousands, or at least what feels like it, on each plane) with no anti-seize applied. Don't worry about it.

[Mark Eaton]

I've never had the occasion to use rib nuts. I am considering them now. My question is--is there a tool that I need to use to install them?

I use this kit and have been happy with it for riv nuts up to 1/4" https://www.summitracing.com/parts/AFS-39314

For 5/16" Riv nuts I use this https://www.mcmaster.com/#96349A407

I use SS or Zinc bolts because they are plentiful at Home depot, etc. and I don't plan on leaving the car out in the rain anyway. Also, the further I progress in my build it is rare that I install any bolt without applying some sort of guey media, be it loctite or Anti-seize. For riv nuts they all get Anti-Seize

[cv2065]

I use the same tool as Mark, but for 10-32 sized rivnuts. Got the idea from Edwardb, and very simple to use and effective. SS screws are easy to find for that size as well. For rivnuts, I'm using these:

https://www.mcmaster.com/#95105A135

These are steel and ribbed to help keep from spinning. They also have a larger flange....

[NAZ]

Here's something to consider when choosing between S.S. and cad plated fasteners most commonly used in rivet nut applications (button head and socket head type screws). Beside being prone to galling, S.S. screws have a lower tensile strength. S.S. screws are typically 70ksi where the good quality cad plated screws (not hardware store made in China screws) are typically 120ksi tensile strength. If you have to drill out a steel screw it is much easier than a S.S. screw. And as a bonus the cad plated screw combined with an aluminum rivet nut is less likely to suffer from galvanic corrosion.

[GoDadGo]

I use the same tool as Mark, but for 10-32 sized rivnuts. Got the idea from Edwardb, and very simple to use and effective. SS screws are easy to find for that size as well. For rivnuts, I'm using these:

https://www.mcmaster.com/#95105A135

These are steel and ribbed to help keep from spinning. They also have a larger flange....

I think, which can be scary, the ribs serve two purposes:

1. The ribs promote the kink and roll over as you compress the rivet-nut.
2. The ribs also reduce spinning once installed.
3. The large flange helps in the event that your holes end up being a tad wonky and/or oversized.

Just understand that I'm no expert, just a 1st-time builder like you; however, I have often slept at Holiday Inn Expresses on more than a few occasions.

[tonywy]

How about Dzus Fasteners ?

[NAZ]

I've made good use of Dzus type fasteners (self ejecting 1/4-turn fasteners) on my latest car. I have quite a few panels that must come off for chassis inspection or maintenance and the quick fasteners are the most practical way to hold these panels. But they are not appropriate everywhere as the fit is not the same as you get with a screw. They require a lot more effort to install and like rivet nuts, they require a special tool to install. But if you have a panel that you need to frequently remove they are the way to go.

[Bob Cowan]

Rivnuts have a flange, obviously. That means the panel will not sit flat on the material that it's attached to. May or may not be an issue, but something to consider. I used a boat load of #10 screws on all the cars I'v built. I'v found - in most cases - it's better to just drill and tap a hole where you need it. Rivnuts are primarily designed for attaching things to sheet metal. Not attaching sheet metal to other things.

[NAZ]

I generally agree with Bob's assessment of rivet nut use and certainly it would not be appropriate to attach sheetmetal to tubing using rivet nuts. You would be making a much larger hole for the rivet nut and taking strength away from the tubing. And since there is a flange on the rivet nut you are spacing the sheetmetal away from the tubing which may or may not present an issue.

However, there are applications where attaching sheetmetal to soft materials not easily threaded where rivet nuts are a viable choice. For instance, I attached a removable sheetmetal access panel on my fiberglass dash panel using rivet nuts. The aluminum access panel holds my RacePak electronic display and allows tech inspectors access to my line lock and electrical system. The sheetmetal cover sets flush with the fiberglass as I counter bored the holes that the rivet nuts are inserted in. But all my sheetmetal that is screwed to tubing is threaded into the tubing or a flat bar welded to the tubing specifically designed for mounting to. You see, it's also generally not a good idea to drill holes in structural tubing (some exceptions may apply) and may not be compliant with sanctioning body rules if you plan to race your car. So there can be more things to consider before indiscriminately drilling holes in chassis members than most folks realize.

[Kiwi Dave]

I use this kit and have been happy with it for riv nuts up to 1/4" https://www.summitracing.com/parts/AFS-39314

For 5/16" Riv nuts I use this https://www.mcmaster.com/#96349A407

I use SS or Zinc bolts because they are plentiful at Home depot, etc. and I don't plan on leaving the car out in the rain anyway. Also, the further I progress in my build it is rare that I install any bolt without applying some sort of guey media, be it loctite or Anti-seize. For riv nuts they all get Anti-Seize


Do you all have some general advice as to when to use (blue) Loctite vs. anti-seize vs. torquing alone when specs are provided?

Thank you

Dave

[cv2065]

Do you all have some general advice as to when to use (blue) Loctite vs. anti-seize vs. torquing alone when specs are provided?

Thank you

Dave

I use blue Loctite on any fastener that could back out due to vibration. Red same thing but for larger fasteners or permanent. Anti-Seize for dissimilar metals, areas where rust/corrosion could occur or high temps

[Avalanche325]

Some of you are way over-thinking this and are way down in the "it could be measured in a materials testing lab" zone. Most of the panels mount to 3/4" square tubing. You would have to make it look like swiss cheese before you had an effect on the functional strength. The difference in the hole for a 1/8" rivet and 1/4" hole for a #10 rivnut will make no functional difference. The 3/4" tubes are much too thin for adequate threads. Until we see the first FFR rivnut induced structural failure (which will be never), I don't think you need to worry.

The only place the flange would be an issue is if you want something to be water tight, like the footbox access panel or transmission tunnel if you do that. On my footbox access I simply made a gasket with holes that clear the flanges. They do make rivnuts that don't have flanges. They are more headache then they are worth.

I used stainless fasteners. I live at the beach and zinc hardware has about the same half life as an ice cream cone. I used anti size on them. As was mentioned, they are prone to galling. I used flat and lock washers. Yes split washers are almost useless, but I haven't lost a panel yet.

[edwardb]

Some of you are way over-thinking this and are way down in the "it could be measured in a materials testing lab" zone. Most of the panels mount to 3/4" square tubing. You would have to make it look like swiss cheese before you had an effect on the functional strength. The difference in the hole for a 1/8" rivet and 1/4" hole for a #10 rivnut will make no functional difference. The 3/4" tubes are much too thin for adequate threads. Until we see the first FFR rivnut induced structural failure (which will be never), I don't think you need to worry.

The only place the flange would be an issue is if you want something to be water tight, like the footbox access panel or transmission tunnel if you do that. On my footbox access I simply made a gasket with holes that clear the flanges. They do make rivnuts that don't have flanges. They are more headache then they are worth.

I used stainless fasteners. I live at the beach and zinc hardware has about the same half life as an ice cream cone. I used anti size on them. As was mentioned, they are prone to galling. I used flat and lock washers. Yes split washers are almost useless, but I haven't lost a panel yet.

X2. Thanks for this. I was 90% into a similar response (overthinking, 1/4-inch hole won't hurt the thinwall tubing, can't thread the thinwall, the slight thickness above doesn't matter, etc.) yesterday but ended up not posting it. I've used #10 rivnuts almost exclusively on my builds where I didn't want to use rivets. Like the splash guards, access panels, under dash panel, radiator surround, to name the ones I can think of. Aluminum rivnuts and flanged SS button head screws. I do put a dab of anti-seize on them and haven't had a problem.

I've used a few larger rivnuts (1/4-inch and 5/16-inch) for a couple things, like the side pipe hangers, side body mounts, etc. They're in another league. Are steel and generally into the thickwall tubing.

[Dave Howard]

To the original question, Flyingcobra, post #10 has the question answered hands down. Avalanche 32 addresses all the other fluff in response #21. But here's something else to think about. How many guys who installed removable tops for the transmission tunnel EVER removed the cover after the car was complete to service.......the transmission? Most guys will never put enough miles on to warrant a transmission fluid change.

[GoDadGo]

To the original question, Flyingcobra, post #10 has the question answered hands down. Avalanche 32 addresses all the other fluff in response #21. But here's something else to think about. How many guys who installed removable tops for the transmission tunnel EVER removed the cover after the car was complete to service.......the transmission? Most guys will never put enough miles on to warrant a transmission fluid change.

Dave,

During the 2016 Hot Rod Power Tour, Tony Zullo, One Of Factory Five's Best & Brightest, had a shifter go out so he had to hack up the trans tunnel top to repair it while on the road.

His problem made me decide to make form follow function and make everything possible easy to get at to the point of using one tool to do it. Fast forward to when my original engine went sour during my early go kart testing meant that my engine block had to be replaced. Being able to remove the top of the transmission tunnel top was a big advantage which I hope I never have to do again.

Last Drive Before Engine Block Debocle:
https://youtu.be/PCngiKoopkA

Engine Pull:
https://youtu.be/Vhbftk4AP4k

Engine Reinstallation:
https://youtu.be/-nVDzIjSjh8

While most folks don't have my good fortune of having to replace a block, it was nice to be able to have access to things that are normally not accessible.

Hopefully I'll be driving soon and I hope you are enjoying your car as much as possible.

Steve