"Push Rivets" for Enclosure Mounting

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For The Popcorn

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I came across an interesting technique for mounting a small enclosure to a panel while working on an exercise bike.

If you've got an enclosure (some great microcontroller project for example) that you want to mount to a panel, you may have a quandary. You can't run screws through the back of the enclosure because you can't access them when the enclosure is shut. Maybe you could get an enclosure with mounting flanges, but that's not always the best look. Double back tape to the rescue. Until you need to take the enclosure off to work on it.

The control box on my exercise bike it mounted to a sheet metal structure. I wasn't sure how it was mounted, as there were no screws from the back. I could see a couple plastic bumps (4 as it turns out) that I took for locating pins with I guessed double-sided tape.

A little gentle prying and the enclosure popped free, revealing the mounting secret. Many companies make variations on this idea, but Essentia Components calls them "push rivets" or "snap rivets". These are inserted through holes in the mounting panel and back of the enclosure, and the button pressed to lock the enclosure in place. They provide a firm grip, but are flexible enough that they give way with no damage when some over-zealous idiot tries to pry the enclosure off.

I've seen these rivets before but never for an application like this. I hope my description makes sense, and that some of you will find it useful.

 

Hi,

They also make the 'screw' type where instead of a push pin you have a screw, and to secure it you screw in the screw instead of pushing in the pin.

My preference is to use what they call, "rivet nuts". These are amazing little fasteners that once installed in a panel provide you with a strong, threaded hole so you can mount something to that panel using regular bolts like M3, M4, M5, etc. I used these to reattach a gas door to an automobile where the plastic push pins had failed.

You need a special tool to install them. You thread the rivet nut onto the tool, insert the nut into a hole you drill or is already present, then spread the handles of the tool. The rivet nut anchors itself to the panel. You then have a threaded hole there.

There is one drawback to many of these solutions. That is, they do not fit perfectly flush to the front surface of the panel they are installed in. They stick out a very small mount. It's not much, but for some application it may not work as well as a real threaded hole. For that you would need regular nuts on the back of the panel, but if you don't have access to the back you have to do something else like use these rivet nuts or something.

The gas door I installed was originally held on with plastic push pin things which were weak and that is why the gas door broke off to begin with. There is supposed to be some break-away action allowance, but the hinge is plastic anyway so if there is too much force the hinge will break, no need for plastic push pins to provide that protection.
 
MrAl said:
You need a special tool to install them.
Click to expand...

Not really. All you need is a scew of the correct size and thread and a nut to fit it. Put the nut on the screw, thread the screw into the rivnut and then tighten the nut while holding the screw from turning. Does the same thing as the expensive tool.
 
And many handheld pop-rivet guns come with adaptors for fitting various sizes of them, it's fairly common.
 

Hi,

Yeah sure, if you only have a few to do. If you have a lot to do it's going to be a pain in the butt to do it that way though (ha ha).

The tools are not that expensive really and they make the installation quick and easy. They also come with a variety of sizes of arbors so you can do many different size rivet nuts, like M3, M4, M5, etc., etc., and also SAE sizes. They also usually come in a nice case that holds everything. They are also made of hardened steel so the bolt part does not break off inside the rivet nut, which could make installation a nightmare.
 
Nigel Goodwin said:
And many handheld pop-rivet guns come with adaptors for fitting various sizes of them, it's fairly common.
Click to expand...

Hi,

You mean you can use a pop rivet gun on a 1/2 inch diameter rivet nut?
I have a good pop rivet gun and it is miniscule as compared to the rivet nut tool. It's made for pop rivets that have a shank about 3/32 inch in diameter or so. Maybe a bigger pop rivet gun, but I could never use mine and it's a pretty good one.
 
MrAl , please don't take every comment as an argument. You brought up a useful piece of hardware that people may not have known about; others were only adding information, not challenging you.

As Nigel Goodwin stated, mandrels for rivnuts are often included with pop-rivet tools. Here's a example.



 


Hello there,

Thanks for the reply and note.

Just so you know, I didn't take it as an argument. I took it as added information except for the fact that I didn't think it would work with the larger variety of rivet nuts. For the smaller ones, I bet it would work, no argument there.

The more regular tools made for this typically have 16 inch handles and have internal gearing to make the installation action more effortless. It takes very little effort with the tool I got and some of these nuts take a lot of force to install because they have to crimp very tightly on the sheet metal so they don't turn when you go to tighten the bolt used for the application.
I also wanted to insure I would be able to use it on other projects too and possibly on some of my neighbor's stuff (some of my neighbors are really great people) that could take bolt diameters of 1/2 inch or maybe even larger.
In addition, I wanted to ensure success because although it was just a gas door, the car is an antique and should have the appearance maintained as the original as closely as possible. If you want to register a car in NJ as antique, it has to look like the original in almost every way, and they make you even bring pictures of the car when you go to register (yikes).
From what I understand, NY is a lot more lenient with this. Any car 25 or more years old can get through inspection with little hassle.

As to the cost, I think I got a good tool and for the price it was a really good value. I paid $30 USD for a tool with 16 inch handles and a host of 'mandrels' for different size rivet nuts from very small to quite large, and a host of rivet nuts that came with it from size M3 and up. I think it was a good value, on Amazon of course (ha ha). It came as a set and in a nice hard case for storage of everything. I got it about a year ago but I think they still have some for the same price, not sure if it would be the same as mine though, but they do come with a set of different size rivet nuts as well. Nice kits.

If you only need to do M3 and maybe M4 bolts you could probably get by with a smaller tool, like even a modified pop rivet tool. The lone rivet nut kits come as low as $10 USD and you get a lot with that, and many different sizes.
 

As this is an electronics forum, and not a forum for excavators etc. we're only concerned with small ones, and the pop riveters are the right tool for the job. Even for just pop-rivets, a small hand held tool will only manage relatively small ones - with the largest suitable rivets being quite hard to 'pop'.
 

Hi,

Yes, and as I said, I wanted to be sure I could cover almost any size I needed. Also, the cost difference seems to be small between a larger solution and a smaller solution. Even with the smaller bolt sizes though the larger the tool the easier it is to compress the insert.

There is one caveat with a larger tool though, if you need to get into small spaces you are better off with a smaller tool because the larger 16 inch handles will not fit in as well of course. In some cases I could even see resorting to the "nut and bolt" method in order to get into very small spaces.

I also saw another interesting attachment for a portable electric drill. The thing goes into the chuck and the drill does all the work when it comes to squeezing the rivet nut onto the sheet metal. Pretty cool and I guess little effort because the drill does most of the work.
 

I would imagine the larger sizes are likely to need a powered solution, or at least considerable gearing, as it's going to take considerable power to crimp them.
 
Bringing this bloviated conversation about rivnuts (related only to the topic of this thread by containing the word "rivet") back to the topic at hand.....


This video showing a similar product appeared in my Facebook feed today. This version uses a screw instead of a push pin to secure the rivet. It will give you some idea of the application. I am in no way suggesting this vendor or this particular product.

The application of securing an enclosure to a panel using push rivets never occurred to me before – I'd had the problem of how to mount an enclosure to a panel when the enclosure must be screwed together from the back before, so I thought this idea might be useful to others.
 
It's common practice, and has been for decades, I used to come across it quite frequently when doing repairs, mostly for holding PCB's in place.

A BIG issue is that as the plastic ages, it goes brittle, and the top snaps off when you try to open them - so you need to knock the inner 'pin' through, using something thin enough.

Then you have to replace the rivet, for that reason I used to keep a couple of common sizes in stock.
 
Nigel Goodwin said:
I would imagine the larger sizes are likely to need a powered solution, or at least considerable gearing, as it's going to take considerable power to crimp them.
Click to expand...

Hi again Nigel,

My tool will work up to 1/2 inch because it has a fairly high gearing ratio and the handles are quite large. Too large maybe for many applications I could easily imagine. I would have my doubts for 3/4 inch or 1 inch, but lucky I do not anticipate needing those large sizes.
I actually used it with M3 and M4 and M5 so far (ha ha).
 

Hi,

I hate those push pin rivets they are too fragile. That's what one of my cars had holding the gas door on to the body of the vehicle. The excuse was that they are supposed to work not only to hold the door on the body, but to act as a sort of protection in case the gas door catches on something. The plastic acts as a breakaway protection so the gas door simply comes off rather than bends the sheet metal of the body.
Notice I used the word, "excuse". That's because when I read that explanation I had to laugh because I had a car for 25 years with a gas door that had completely metal for everything, including the hinges and bolts to hold it onto the car body, and it never once bent the sheet metal of the body of the car.
The hinge on this other car is also plastic, so i would expect that to act well enough as protection against that rare occurrence.

I actually tried using push pin rivets first, but the pins broke in half with just a small amount of pressure trying to install the dang things. I knew there had to be a better solution and that is when I found the rivet nuts.

The other problem is that if you do use push pin rivets on the gas door and it breaks off when you are on the road and you don't know it, you LOSE the entire gas door somewhere on the road and may not be able to find it when you retrace your route, once you realize it is gone. With a late model car this may not be a huge problem, but with an antique car it can be hard to find a replacement, and it really has to be the same color as the original also.

All this leads me to like metal rivet nuts better than push pin rivets. The rivet nuts come in stainless steel and hardened steel also with a rust resistant finish.
 
You often get a wide range of different plastic 'rivets' or 'clip' holding internal car trims in place, and these often break when removing them - so garage mechanics commonly have a kit of the different types. You can order them off Amazon etc. as well.
 

Hi,

Oh right I had that unfortunate experience also when I dug into one of the door panels on same car.
For another car, I may end up digging into all four doors (yikes). I'll probably need a ton of those plastic things (ha ha).
 
For The Popcorn said:
Well, that didn't work so well, did it?
Click to expand...

Hi,

What is it about rivet nuts you don't like, is it because rivet nuts are made out of metal or because rivet nuts are rivet nuts. Rivet nuts by any other name are still rivet nuts. Rivet nuts, rivet nuts, rivet nuts (ha ha).
Just kidding around here ha ha.

More seriously, they do make plastic ones too I think but will not be as strong. The ones I did see look like they have something like a sheet metal screw that screws into the plastic, and the plastic expands on the inside side of the sheet metal.
I realize that there are other solutions too, but some of them require that you have access to the back of the panel. I didn't have access to that without taking apart a lot of other stuff inside the car and possibly messing up the seal of the gas neck to body interface.
At first though I almost had a heart attack when I saw that the push pin things did not work at all. I paid a lot for the new hinge and plastic push pin rivets and watched the video that came with it carefully on how to install it using the push pin things but they still broke easily.
 
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