How strong is a rivnut?

[JJ99SS]

I've done some digging (searching) around in here and still had a few questions...

I'm looking at installing some L Track in my truck bed for tie downs and to bolt a mount for a Hi Lift Jack. I'll likely use the stainless bolts they sell for the bed rails, as I can put washers and really clamp onto the sheetmetal. The WLL is 1666 lbs for just one of the clips that go into the L Track (common for strapping ATV's and motorcycles). I don't think I'll be using it for anything that heavy duty but you never know.

https://www.uscargocontrol.com/shop...irline-Straps-Hardware/L-Track-Tie-Down-Rails

The problem is between the cab and the bed there is no room for a wrench. So to save me the time of removing the bed and sliding it forward, I thought I'd use rivnuts. From what I can see, the area where I'd likely be drilling seems to have at least two layers of metal maybe a few millimeters thick.

If they are strong enough I'll likely use them in the floor of the bed as well, also to keep me from removing the bed. Although the metal seems thinner in these areas.

A 48" piece of L Track has 10 mounting holes.

What say you guys who have used these?

Also it seems the Astro tool seems to be the go to on Amazon for $60...

 

[gnxtc2]

You're in luck, I installed the same L Track in my trailer and utilized the 1/4-20 rivnuts that came with the track. I fastened the L Track every 16" on my trailer's support channel (aluminum) and it was plenty strong. You're biggest issue is going to be how strong the metal is that the rivnut is going in. You might need to double up the backside of the rivnut. McMaster has few different variations of rivnuts.

Billy T.
[email protected]

 

[toplessHO]

most beds come off with 4 or 6 bolts
cover the bumper,get some help and slide it back 6 inches to gain access.
Then you can install plates to back up the sheet metal

 

[Astro_Pneumatic_Tools]

I would venture to guess it's possible we may sell more rivet nut tools than all other brands combined in the U.S., so happy to help if you have more questions.

To the original question (for our rivet nuts), used in the way you describe as there are lots of force directions and scenarios:

Fastener pull out strength
1/4-20: 475lbs
5/16-18: 520lbs
3/8-16: 610lbs

Keep in mind while that is per rivet nut, rarely is there an impact or force that will try to pull out fasteners all equally at the same time. So while adding rivet nuts increases strength, it just increases an average.

 

[eyeball]

For what it’s worth... I secured two strips of that track to the bed of my Jeep Wrangler with rivnuts. When I pull out the rear seat to go wheeling, I use the track to strap tool boxes, ice chests, spare parts box etc and they never budge.

Keep in mind I primarily do rock climbing at relatively slow speed (once I get there)

Regarding the strength of rivnuts... in the Jeep world, that is the primary fastener used to secure body armor, rocker sliders, etc. however, those are not typically areas that are subject to pullout forces.

 

[JJ99SS]

That's perfect info guys. I have an 04 Tacoma double cab, that I off road as well. I need to secure camping equipment, high lift, and coolers as well. So not really anything too heavy until I'm hit up for moving duties again.

I'll look into unbolting the bed, but if I do I'll just use bolts and add bigger washers. I had thought of using strips of either aluminum or steel behind there to add material or strength but again no access.

If I do unbolt the bed, I'll likely use larger washers there as well. The rivnuts sure would be quicker however, because lifting the bed and threading all those nuts and bolts under the chassis but above the fuel tank will be a pain in the *** with just me.

 

[rlitman]

I would venture to guess it's possible we may sell more rivet nut tools than all other brands combined in the U.S., so happy to help if you have more questions.

To the original question (for our rivet nuts), used in the way you describe as there are lots of force directions and scenarios:

Fastener pull out strength
1/4-20: 475lbs
5/16-18: 520lbs
3/8-16: 610lbs

Keep in mind while that is per rivet nut, rarely is there an impact or force that will try to pull out fasteners all equally at the same time. So while adding rivet nuts increases strength, it just increases an average.

I like this answer, but it leaves me with a question. Are those numbers quoted for aluminum or steel rivet nuts? Or does it even matter much? The tensile strength of a 1/4-20 grade 2 rod is over 2350 lbs, so, is it the threads pulling out (which I've seen in aluminum rivnuts), or the whole fastener pulling through the sheet metal that is the limiting factor?

To that end, the OP might want to consider pre-bulbed "plusnuts". A 1/4-20 Plusnut is rated for 1215 lbs of pull out force in sheet steel. That's probably as strong as a nut and washer from beneath.

 

[Astro_Pneumatic_Tools]

Steel rivet nuts - we don't make aluminum. Steel sheet metal.

Tensile strength of a fastener is not equatable to pull out strength of a rivet nut. Plus-nuts aren't always the best choice, but yes in pull out strength they are better.

 

[rlitman]

Steel rivet nuts - we don't make aluminum. Steel sheet metal.

Tensile strength of a fastener is not equatable to pull out strength of a rivet nut. Plus-nuts aren't always the best choice, but yes in pull out strength they are better.

Thanks! I only brought up the tensile strength as an absolute maximum for comparison sake. I mentioned aluminum, because I have some from Marsen, and well, I'd say that they're absolutely not up to the OP's task. I think that steel should probably be fine.

Completely agreed regarding the Plusnuts. I can't say I've run into a use for them yet in my own projects, but they seem perfect for the OP.

To the OP, remember that no fastener will be stronger than the sheet metal it is attached to. And if you put too much reliance onto too few fasteners, you'll just bend the sheet. But the track makers are well aware of this, and should give you plenty of holes to get it secure.

 

[6PTsocket]

Steel rivet nuts - we don't make aluminum. Steel sheet metal.



Tensile strength of a fastener is not equatable to pull out strength of a rivet nut. Plus-nuts aren't always the best choice, but yes in pull out strength they are better.

I have one of your rivnut sets. 1442 (improved blue version with simplified design). Are the optional additional sizes still available? I just looked up plusnut to see what it is. It looks like a moly for sheet metal. If the metal is heavy enough and you use the right length rivnut, I don't see a regular rivnut pulling out very easily. I would think that shear strength might be more of a weakness compared to a nut and bolt.

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[rlitman]

... I would think that shear strength might be more of a weakness compared to a nut and bolt...

A nut and bolt in sheet metal gets much of its shear strength from the clamping force. If we're talking about a "loose" connection, the rivnut will win, because it has a larger OD that's less likely to tear through the sheet.

The Plusnut is exactly a molly for sheet metal. I brought it up, because it expands more on the back side, so it gets you as close to having a nut and washer on the back as you can get without requiring the back-side access. If you're using it in a spot where it has room to expand... Rivnuts can fit into tighter spaces.

 

[Astro_Pneumatic_Tools]

I have one of your rivnut sets. 1442 (improved blue version with simplified design). Are the optional additional sizes still available?

Yeah, pm me sizes you need

 

[JJ99SS]

Thanks! I only brought up the tensile strength as an absolute maximum for comparison sake. I mentioned aluminum, because I have some from Marsen, and well, I'd say that they're absolutely not up to the OP's task. I think that steel should probably be fine.

Completely agreed regarding the Plusnuts. I can't say I've run into a use for them yet in my own projects, but they seem perfect for the OP.

To the OP, remember that no fastener will be stronger than the sheet metal it is attached to. And if you put too much reliance onto too few fasteners, you'll just bend the sheet. But the track makers are well aware of this, and should give you plenty of holes to get it secure.

Agreed. There are ten mounting holes in a 48" section of track. Should be plenty. I'll check the gauge of metal in the bottom of the bed somehow. Along the back of the bed, there seems to be additional material where I'm looking for added rigidity from the factory. No issues there I believe.

This is going to be expensive. Just received a quote for $450 for Linex in the bed plus $150 for the track. $50 for nuts and bolts. Factor in rivnut tool, rivnuts and I'm going to be in almost $800. All so I can secure a cooler...