Blind (POP) Rivets 101
What Is A Blind Rivet?
Blind rivets, also commonly referred to as POP Rivets, are mainly used in applications where there is no access to the rear (blind side) of the joint. Rivets have a two-piece construction; one is called the rivet body, shell, or hat and another is called the stem or mandrel. Both the hat and mandrel are pre-assembled and ready to use. Rivets are installed by using a riveting tool to draw the mandrel which causes the body to deform and clamp down on the joint. Upon reaching the designed clamping force, the mandrel snaps and is discarded. A benefit of blind rivets is that they are not material specific meaning they can combine two different material types together the same way.
To use a blind rivet, a hole is drilled then the rivet is seated inside of the hole. Then a tool pulls the mandrel against the hat of the rivet. The back of the mandrel either has a bulge on the end or is connected to the hat in some way which makes the edges of the hat expand down towards the material. Once this expansion reaches the material and builds pressure, a designed fault in the mandrel reaches its peak force capacity and snaps. Leaving a properly installed rivet.
One of the biggest benefits if rivets is that there is no way to over or under-torque a rivet. If the appropriate diameter and grip range and chosen the rivet will install perfectly every time.
Common Blind Rivet Applications
POP Rivets can be used just about anywhere if they are properly installed. Most of them are used in RVs, Trailers, Aircrafts, Machinery, Jeans, Small Electronics, Structural Beams, Battleships and Submersibles.
Installing a Blind Rivet
Before rivet installation can occur, several things must be taken into account.
|Materials||The softness/hardness of the materials may be enough to change grip range or head style during installation. Rivets come in either all one material or material/material options.|
|Rivet Material||The rivet material must be chosen based on environmental factors, strength, corrosion resistance and installation materials.|
|Head Type||There are several different head styles covered later in this article.|
|Rivet Length||The length of the rivet will change the grip range.|
|Rivet Diameter||The rivet diameter determines the size hole that needs to be drilled.|
|Grip Range||A rivet's grip range is the range of how thick the material can be for a proper installation.|
Installing a blind rivet is a simple and extremely fast process which is what gives POP rivets their excellent reputation. Installing them requires only the few simple steps listed below.
- Drill a hole into the materials.
- Choose a place the rivet into the two materials.
- Place the Rivet Installation Tool on the mandrel of the rivet.
- Activate the tool (usually by some lever or trigger mechanism) to pull the mandrel towards the surface.
When the mandrel gets tight in the material it will snap off at a predetermined point leaving the hat with a portion of the mandrel stuck inside. A properly sized and installed blind rivet will hold tightly and strong as a permanent joint in the materials. If the hole was too big the rivet will be loose and spin and if the drilled hole is too small the rivet will not install correctly leaving a bad seal.
Rivet Size Guide
How to Measure a Rivet
- Measure the diameter of the rivet itself with a dial caliper or a measuring gauge.
- Measure the underside of the rivet head to the end of the rivet head. *Don't Measure the mandrel. The hat length it what you are looking for.
- The grip range of the rivet will be shorter than the measured length. The measured length will be 1.5x the rivet's grip range (including the ball at the end of the rivet).
EXAMPLE: If the length of the hat is 1/2" the rivet has a 3/8" grip (.375), also known as a 4-6 rivet. Please refer to the diagram and charts below for grip ranges
- Mandrel - Long end that is broken off the rivet during installation
- Hat - Portion of the rivet that is inserted and expanded to fit a hole
Understanding Rivet Grip Range
Here is an example of calculating rivet grip range using a:
6-6, 3/16" STAINLESS STEEL OPEN END DOME HEAD POP RIVET
6-6 = X-Y
Where X Represents Diameter in X/32 and Y Represents Max Grip Range in Y/16
(X=6, 6/32 = 3/16) Diameter = 3/16
(Y=6, 6/16 = 3/8) Max Grip Range: 3/8
6-6 = (3/16 x 3/8)
Grip Range .251-.375
Rivets come in a variety of types each of which have benefits.
|Open End||Open End Rivets are the most popular rivet variety available. They rely on the balled end of the mandrel going into the hat forcing it to expand.|
|Closed Ends||Closed End Rivets are used for applications where the installed rivet will be exposed to liquids or vapors. The sealed end prevents liquids from going through the rivet into the installation or speeding up the corrosion process.|
|Multi-Grip||Multi grip rivets have a significantly wider grip range than standard POP rivets. They are commonly used to substitute conventional rivets where the material thickness varies.|
|Tri-Fold (Exploding)||Tri Fold or exploding rivets have a wider grip range due to the way the hat bulges. They also resist pull-though by having three folds distribute the pressure over a wider surface area.|
|Interlock (Structural)||The mandrel locking mechanism on these rivets create a stronger assembly than other types. This type is recommended for structural applications.|
|Painted Head||Painted rivet hats to match your applications to leave a blended less noticeable rivet in its place.|
The head refers to the washer-like portion of the hat on a rivet. Just like with the type, each variety of head comes with its own benefits that should be considered.
|Dome||The dome head sits rounded and exposed when finished.|
|Large Flange||Large Flange rivets have a wider hat to better distribute surface pressure and prevent pull-through.|
|Shave Head||The mandrel snaps further up on these rivers requiring a cutting and filing tool to shave them down to a clean finished look. They are exceptionally popular as trailer rivet replacements.|
|Countersunk||A Countersunk head sits almost flush with the surface when installed.|
|Low Profile (Flat Head)||These heads are almost the same as a countersunk but sit up slightly higher.|
Rivet tools (Riveters) are the special tools used to install rivets. There are several types available and options can vary depending on the size of the rivets.
|Hand Riveter||A very common rivet tool that is simple to use and requires only a squeeze or two to set the POP Rivets.|
|Lever Riveter||A tool with two handles designed to drive stronger rivets such as structural. Some include a bottle to catch the snapped mandrels for ease of cleanup.|
|Battery Powered Riveter||Like a cordless drill, a battery riveter uses a trigger and automatically pulls and spits the mandrel. Some have a catch that will draw the mandrel in for ease of cleanup.|
|Pneumatic Riveter||An air powered rivet tool that quickly and effectively installs rivets. The only downside is needing compressed air to use.|
How To Remove A Rivet
Blind Rivets are meant to be permanent joints but sometimes must be removed. To remove blind rivets, take a drill bit that is the same diameter as the hat or a size larger and drill through the rivet. Make sure the drill bit is rated for the rivet material. If before or during the rivet drilling process the rivet begins to spin, stop and cover the rivet in blue painters or duct tape. This should be enough to hold the rivet in place as the drill eats through it. Once extracted, the same hole can be used for a new rivet.
Rivet washers are useful tools to have handy. There are two main types of rivet washers. The metal ones that sit below the hat which increases the pull-through resistance and pressure distribution of a rivet and the neoprene (rubber) washer that sits below the hat to seal a hole. When using the metal washers be careful to ensure the washer's thickness is included in the thickness.
Rivet Size Guide
|Rivet Series #||Nominal Size||Drill Size||Hole Size |
Max - Min
|Rivet #||Grip Range |
0.100 - 0.097
0.133 - 0.129
|4-1||0.020 - 0.062||0.212|
|4-2||0.063 - 0.125||0.275|
|4-3||0.126 - 0.187||0.337|
|4-4||0.188 - 0.250||0.400|
|4-5||0.251 - 0.312||0.462|
|4-6||0.313 - 0.375||0.525|
|4-8||0.376 - 0.500||0.650|
|4-10||0.501 - 0.625||0.775|
|4-12||0.626 - 0.750||0.900|
|4-14||0.751 - 0.875||1.025|
0.164 - 0.160
|5-2||0.063 - 0.125||0.300|
|5-3||0.126 - 0.187||0.362|
|5-4||0.188 - 0.250||0.425|
|5-6||0.251 - 0.375||0.550|
|5-8||0.376 - 0.500||0.675|
|5-10||0.501 - 0.625||0.800|
|5-12||0.626 - 0.750||0.925|
|5-14||0.751 - 0.875||1.050|
|5-16||0.876 - 1.000||1.175|
|5-18||1.001 - 1.125||1.300|
0.196 - 0.192
|6-2||0.020 - 0.187||0.325|
|6-3||0.126 - 0.187||0.387|
|6-4||0.188 - 0.250||0.450|
|6-6||0.251 - 0.375||0.575|
|6-8||0.376 - 0.500||0.700|
|6-10||0.501 - 0.625||0.825|
|6-12||0.626 - 0.750||0.950|
|6-14||0.751 - 0.875||1.075|
|6-16||0.876 - 1.000||1.200|
|6-18||1.001 - 1.125||1.325|
|6-20||1.126 - 1.250||1.450|
|6-22||1.251 - 1.375||1.575|
0.261 - 0.257
|8-2 ||0.020 - 0.125||0.375|
|8-4 ||0.126 - 0.250||0.500|
|8-6 ||0.251 - 0.375||0.625|
|8-8 ||0.376 - 0.500||0.750|
|8-10 ||0.501 - 0.625||0.875|
|8-12||0.626 - 0.750||1.000|
|8-14||0.751 - 0.875||1.125|
|8-16||0.876 - 1.000||1.250|
|8-18||1.001 - 1.125||1.375|
|8-20 ||1.126 - 1.250||1.500|
|8-22 ||1.251 - 1.375||1.625|
|8-24 ||1.376- 1.500 ||1.750|
Helpful Rivet Resource Videos:
Rivet Measuring Transcript
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Bob: Welcome back to Albany County Fasteners - Fasteners 101. I'm bob and today we're going to teach you how to properly measure a blind rivet. So let's get started.
I'm going to teach you how to properly measure a rivet. We get a lot of phone calls from buyers wanting to buy a rivet thinking that a rivet is measured under the hat to the end. Which is totally false. A rivet is measured by the installation thickness of the material you're going to be installing it in. So if you're installing two pieces of metal together, to select the correct rivet, you need to measure the thickness of those two materials together. At that point you would have the total amount of product that you're going to be gripping to fasten together.
So when you measure, when you receive your rivets, don't take a tape measure and measure from this point to this point. That's not going to be correct. You're going to find it's going to be about an eighth of an inch to three sixteenths of an inch longer than what you purchased.
So the correct way would be to get one of these babies. Ok, this is called a rivet measuring tool and to find the correct measurement that you want, here's how to measure a rivet. So it has all of the sizes on the side here, which are gauge, they go from size 3 all the way up to size 8. So I'm going to try to stick it in the hole. It won't go into a 3 but it goes right into a 4. So this is a 4, I know it's a 4 because I picked it.
Okay so we know it's diameter is a number four and then we're gonna be looking for length. It won't fit into this, this is where you find out the length. So it's the second one and it comes in right at 4-4 so this is a 4-4. 4 being the diameter and the next 4 being the length.
It can come in 4-2, 4-4, 4-6, 4-8, all dependent upon the amount of material you're going to be gripping. And that's basically how you measure a rivet. You do not measure a rivet with a ruler.
Rivet Types and Materials
Installing POP Rivets Transcript
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Bob: Welcome back to Albany County Fasteners - Fasteners 101. I'm bob and today we're going to teach you how to properly install a blind rivet. So let's get started.
So I'm going to install several rivets. The first one I'm going to install is this copper rivet with the standard rivet hand tool. I'm going to put in the mandrel. The mandrel goes in to the tool first. Like this. All the way in. Now, I'm going to place it.
I'm using a piece of structural steel. This is just for demonstration. I pre-drilled the holes already. Not to bore you with drilling holes. So I figured I'd just knock this out for you.
Then you just put it in and you squeeze it (SNAP!). Until you get the snap. And that baby is installed. 1-2-3.
So that's the copper rivet installed. I'm going to grab another one this is a closed end rivet. You can see that the closed end has that flat-bottomed square finished off, waterproof end. So I'm gonna install one of these right now with the standard rivet gun.
Pushed it in. BAM!
You can see it's not loose. Perfect installation.
One thing I would caution you on is to drill the correct size hole for the rivet. The rivet should have no slack when you drill a hole. It should be tight right against the rivet. Actually, you should force the rivet in place. A little bit. It should just be like, friction fit.
I'm going to install now a white rivet. I'll turn this around when I'm done, later so you can see the finish and the back.
That's what you get after you pop the rivet. You get a broken mandrel. It cuts the mandrel right off.
I'll install a black rivet, I'm sorry, a brown rivet.
You can see it's pretty easy. No Force. Ya know? You don't have to struggle with it.
This one is stainless steel. A lot of people call me and they say: "Hey Bob, why is it, is it harder to install stainless steel?" I'm going to show you right now it's not harder. It's the same thing.
Snapped off. It's installed fine. There was a little bit more resistance but, you know, its not any different than putting in anything.
This is the multi-grip. So this is a fabulous fastener they came out with. This particular fastener, they made it so if you're, you know, have multi-applications you can use this and it breaks at each one of these points: 4-2, 4-4, and 4-6.
Ok, so you can break in any of these areas. I'm gonna install that now; let's see how that works. I've never used one of these myself but here's the first time.
So there's double the pull so it keeps pulling it in. You can see in the back here. There it goes.
So it's a double action, you have to push the lever twice.
Basically, that's it other than the structural so these structural (rivets). These structurals are installed using a different tool. The structurals are installed with a tool like this. Which is one of these monster-they're almost like a bolt cutter-type of riveter because you're going to need some leverage. These are like quarter inch. I didn't drill holes for this but I just figured i'd show this to you. What it looks like. This is a pretty heavy-duty structural. You would use these in structural applications.
So that's a wrap on us showing you how to install. I'm gonna twist this around for you so you can see the finished product. Ok here is the, that's the front. They are all finished, all in there very well. And then I'm gonna show you the back; that's the side that you wouldn't see.
That's why they call them blind rivets. Because of the backside. You put them into a hole that you're trying to fasten two pieces, you can't get to the back of it with a nut and try to hold it while you put a screw in. This is the perfect application. There you go.
So now I'm going to demonstrate to you the installation of the pneumatic rivet gun. This is a really cool tool. It's quick. It's fast. If you're in a production line, that you want to produce quick action riveting. This is the tool for that.
So I'm just going to install the mandrel into the rivet tool. This is, I didn't show you this, well I showed you this one but I didn't install it before. But this is a large flange (rivet)and I'm just going to install it. Watch this.
Fast action. Quick. The material doesn't matter; it can be stainless, it can be aluminum, it can be steel. It doesn't really matter, whatever you put it in. This tool, will get the job done. Fast.
How to Remove a Pop Rivet
Uninstalling POP Rivets Transcript
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Bob: Welcome back to Albany County Fasteners - Fasteners 101. I'm Bob and today I'm going to demonstrate to you how to remove a structural rivet.
So the first thing I'm going to do is use my punch and I'm gonna punch a hole, so I have a starting point for my drill. I'm going to add some lubricant to my bit. As I always do. Then I'm gonna, find the center here. Now, this is a structural rivet, that I'm removing. That's in place and we're gonna clear the hole out.
Of course, you should be using protective glasses and gloves while you're doing this. Almost there.
There we go. Drilled the rivet out. That's the head of the rivet. Backside comes right out.
Takes ya less than five minutes, not even a couple of minutes you can drill the rivet right out. The rivet, so if it's a quarter inch rivet, like we used here, you should use a quarter inch bit to remove the rivet or a three-sixteenths bit but nothing smaller than that. And nothing larger if you don't want the hole to be over-sized and you're going to reuse the hole again. So you basically want to use the same size as the rivet that you installed originally.
That's how you remove a structural rivet or you can remove any POP rivet, in this demonstration here.
How to Remove a Spinning Rivet
Shear and Tensile Strength
Minimum Shear Strength (lbs)
Maximum Shear Strength (lbs)
|Grade 11||Grade 19||Grade 30||Grade 51||Grade 11||Grade 19||Grade 30||Grade 51|
The grade of material will directly affect the materials strength.
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