No test between the two but here is a crude pic with a comparison of a rivnut and Nutsert in 1/4-20 size. The zinc plated rivnuts that I now use on the left and the cad plated Nutsert I used to use on the right. Notice on the Nutsert there are very small knurls that are supposed to help in not spinning as well as not much flange on the top side. The rivnut, however, has a lot greater grip range (.027"-.165") with a long knurl and larger flange. That's the McMasterCarr pt #in sharpie on the bag if you are looking to buy some. I don't use the nutserts anymore.
My Mistake.. RIVNUTS are what I use.. I saw the first photo and looks like the stuff I have.. Should have done a double ckeck on the set.. I knew someone would correct it.. I'm old.. I've never used nutserts ever..
Also mil spec RIVNUTS have a tang on them ,You notch the hole once drilled ,the tang keeps them from spinning like the common problem with nutserts, You can also get them in countersunk so they fit flush..I'll see if i can post some pics of the ones i BORROWED before i retired.
I have not used the mil. spec nuts with a tang on them, but that seems like that would be the best way to go. Would Aircraft Spruce or someone like that have them?
I guess they might,Mil Spec is only available in 6/32 8/32 10/32 and so forth,They also make a tool that makes the notch in the hole .Easy way to do it.I picked one up on ebay under aircraft tools. It was pretty cheap like $14.00.B F Goodrich made a lot of the AC Rivnuts
Rivnut is actually a trademarked fastener originally produced by BF Goodrich. As described above as a "Mil_Spec" rivnut, the "locking" version will have a tang under the head is matched to a notch installed after drilling the hole. These are easy to torque out and will result in a spinning fastener: The picture shown in the previous post above with the McMaster part number are actually called Rivet Nuts by McMaster. This is the style manufactured by AVK Industrial products, and they call it a knurled threaded insert.. In our use of these style fasteners over the past twenty plus years, we have found the Mil Spec/ BF Goodrich version easy to over torque and causing them to spin. The AVK /McMaster style shown with the splines are about as good as it gets to prevent spinning after installation. With any of these fasteners, you have to be aware of the grip range, so the "bulge" sets behind the panel to prevent failure when the tensional load is applied. Too small a grip range and this bulge sets within the hole, where once tensional load is applied the fastener is doomed to failure/pullout, as in this one we found this morning during some retrofit work....see attached below.. The grip range on this fastener was insufficient for the metal thickness, thus the tension load failure. I would have also chosen a different style than what was used. Gotta love fixing other peoples work..
Rivnuts is the proper name for them and yes they are way better than nutserts which are typically smooth, do not bite as well and have limited torque abilities. Rivnuts are all I use, the tools I have to install them are made in England. Properly installed rivnuts up to 3/8" diameter will take as much torque as a regular nut. As I mentioned earlier there are also several styles of heavy duty versions that spread out differently and hold great also. The aircraft people love them, so do I. Something else to keep in mind is that they are designed for a specific thickness of material. A lot of the "pull out" or spinning problems come from trying to install one made to a length for sheetmetal into thicker material (where a longer rivnut needs to be used) resulting in poor performance. They are like any other mechanical component. They must be chosen correctly and applied properly.
Rivnuts require the proper setting tools to install them. I have a hydraulic puller for the smaller ones and screw type tools for the 5/16 and 3/8 sizes. They have ball thrust bearings on the puller screws to deal with the force required to set them properly.
Good input and yes they can be over torqued and can spin, But like anything else you have to pay attention to what you are doing, You can over torque anything if you want to. Your are right about grip range.
I use them at work most days with great results, mostly on panel steel. They come in light and heavy duty and different grip ranges. Sorry we work in metrics here but a standard 8mm item uses an 11 mm hole where the heavy duty 8mm uses a 13.5mm hole and take a bit of effort to pull up. They have there place but I don't use them on major things such as body to ch***is type stuff. I also always run a tape through them after fitting as they can pull on a slight angle and this trues them up. JW
Ok, spent most of the day yesterday and all morning ****ing around with 6 nutserts. They were steel and 1/2-13 threads - heavy duty rascals. These were EOM installed in a tube frame under a jeep to hold the skid plate crossmember. What a PITA!!!!! Anyone who contemplates this, well you've been warned. It may get you done quickly but It's a very bad idea for future work.
re "aviation use" ; They are used for non structural applications,...ie, interior trim and the like. NEVER for critical components. 4TTRUK
I use Allen Nuts (look them up in McMaster carr) welded into the frame rails. Very tough and can't ever pull out. Rivnuts are OK in lighter duty applications.
home made tool http://s210.photobucket.com/user/la...13-09-09/016_zpsb11363b9.jpg.html?sort=3&o=19 http://s210.photobucket.com/user/la...13-09-09/014_zps3dec979d.jpg.html?sort=3&o=21 http://s210.photobucket.com/user/la...13-09-09/013_zpsb3ead438.jpg.html?sort=3&o=22 http://s210.photobucket.com/user/la...13-09-09/011_zpsc906a0ba.jpg.html?sort=3&o=24
The Jalopy Journal
