Rivnuts anybody

[catfood]

A friend of mine who has just built a replica Stratos was horrified at the thought of using self tappers to attach the p-clips etc. He recommended rivnuts. As I'm not averse to improving things where I can has anyone used them or got any opinions?

 

[BigGreen]

Somewhere on this forum I saw someone use them for attaching the heat insulation near the exhaust
Self tappers tend to break the material (forced by the thread), rivnuts don't

 

[PAUL161]

Rivnuts are cheap, the proper insertion tool isn't. Unless you have enough use to warrant buying the tool, rent one if you can. JMHO, PJ

 

[Roger]

For the limited use it gets, I have found the Harbor Freight tool perfectly adequate for setting Rivnuts and not too expensive at $20 or so.

 

[Randy Forbes]

Rivetnuts and (primarily, nutserts) are holding most of my car together! Also use them on BMW mods too.

Ironically, I bought the set__tool and an assortment os styles and sizes__to fix an aluminum screendoor, back in the the 80s. For my application, buying the best quality tool paid off, as it has seen regular use for over two (>2) decades, and is none the worse for wear today.

Nutserts in practice:

 

[GregW]

I've had rivnuts spin on me (factory installed). What a pain to get the screws out when that happens.

 

[Keoke]

I've had rivnuts spin on me (factory installed). What a pain to get the screws out when that happens.

I was afraid of that so i always coated the nut with JB Weld before i set it none came loose.

 

[Healey Nut]

I've had rivnuts spin on me (factory installed). What a pain to get the screws out when that happens.

Rather than trying to remove the screw/bolt when the insert spins . Tighten it and further collapse the insert to tighten it in the hole then remove the screw/bolt .
I did some today on the Vantage for my custom front licence plate bracket , all worked like a charm .

 

[GregW]

In my situation, the rivnuts spun freely, including in the righty tighty direction. It was one of those arcade basket ball games that I had to dismantle enough to get it into a bar set for a TV show. Wound up grinding the screw heads off.

 

[Michael Oritt]

I had the same thing happen with a custom aluminum radiator. The mounting points were via Rivnuts and one of them spun freely and I could neither tighten nor remove the machine screw used to mount the rad. Ultimately I was able to jam the insert by working a very sharp chisel under the shoulder which allowed me to remove the screw. The failure was probably a function of both the aluminum's softness and the thin section which would not stand up to normal tightening torque. I ultimately removed the Rivnuts and had the holes welded up so that they could be drilled and tapped.

I think they are a great tool when used in the right place, esp. where a fastener must be removed and reinstalled, etc. They are definitely better than running a tapping screw into sheet metal.

 

[steveg]

U-nuts are an option for hidden areas where things have an edge nearby. I'm using them on my heater blower mounting feet and some hidden stuff behind the grille. You won't have the spinning problem.

 

[roscoe]

Nut clips as Steve illustrated above are available for coarse thread style sheet metal (PK) screws, often referred to as Tinnerman nut plates, or machine screw thread pitches as his illustration shows. Some even have floating but captured nuts in them so that you don't have to line all the holes up exactlly. Tinnerman nuts are available through most aircraft supply houses. I've used them in some places where you won't see them and the sheetmetal screw holes were hogged out due to repeated use and became oversized.

 

[steveg]

Agree most u-nuts are coarse thread. The ones I used are 1/4-28 and 10-32 and look like the one above.

 

[pan]

Did you know than all BN1s have one rivnut installed from new? The gearbox oil filler plug hatch is located with one.
And the transmission tunnel, being aluminium sometimes allows the nut to spin!

 

[catfood]

Thanks for the comments guys. I bought myself a tool and some stainless steel rivnuts at the Practical Classics show yesterday. I'll have a practice on some scrap and see how I get on before using them in anger.

 

[Randy Forbes]

Thanks for the comments guys. I bought myself a tool and some stainless steel rivnuts at the Practical Classics show yesterday. I'll have a practice on some scrap and see how I get on before using them in anger.

That's a very good approach!

It's critical to use the right size drill-bit for the application, and NO WALLOWING out the hole; I especially like it when I have to use some force to get the nutserts into the hole (my preference over the rivet-nut variety).

When possible, try to find inserts that are knurled around the top; these will bite into the panel much better, resisting any tendency to spin out.

And lastly, you may have to play with how much pressure you use when setting the insert; too little and it will spin right out, and too much can damage the internal threads of the insert from the much harder mandrel acting against it. If you have a squeeze-type tool, unless you have really big hands (in that case, you have my sympathy when trying to work on sportscars!) it's hard to crack the insert started, and get it set all in one pull. My method is to adjust the insert in the tool so that I don't have to spread my hand very far; 1st pull cracks the insert's deformation phase, and then I keep turning the mandrel into the insert and giving a little more squeeze, walking it home.
Doing it this way, I also am aware of the first sign of the mandrel getting too tight in the threads, and know when it's done. Even so, I sometimes have to use a pair of pliers on the end of the mandrel (the mandrel's holder, to be precise) to loosen it enough to remove the tool by hand.

 

[catfood]

Randy, thanks for the advice. I'll bear it in mind.

 

[steveg]

Pegasus has rivet nut setters in fine threads for $11.99.

I ordered the 10-32 and 1/4-28 models:

Rivet nuts are available for good prices from Hansen Rivet in Pacoima, CA.

 

[Michael Oritt]

Rivnuts are elegant but require a special tool and can spin, etc. U-nuts are primitive and can only be used on the edge of material but they are cheap to buy or replace and will not let you down. I have one installed at the front of my CAB where a custom round-to-square adaptor for the fresh air hose attaches.

 

[John Turney]

I use them to hold my transmission tunnel in place.