What happens is that the rivnuts will gall on the softest material and then rotate. The stronger the bolt to rivnut meshing the bigger the problem unles you use torque wrenches every time. Thats exactly what happens as you tighten the bolt up. The probelm is that the rivnut relies on its crush generated clamping force to resist torsion. One thing I didnt mention - probably obvious - is to be very, very careful to deburr the holes both sides. I think you will need a power tool to pull them. To get a panel to fit perfectly flush you need the countersunk kind I imagine that if I had used steel rivnuts it would have worked OK.Īlso there are countersunk and non countersunk ones. Then teh undertray can be pushed over a steel thread and a locknut run on afterwards. In the end I ran a screw from the inside through the rivnut so it stuck out as a locator stud. Because the undertray was large and floppy it was hard to start each capscrew and I crossed the rivnut threads ruining them. The alloy threads arent that strong and there is no locknut so use Loctite every time if you can.ĭon't make my big mistake!! - I had to attach an aluminium undertray/venturi so I installed the rivnuts on the chassis and planned to offer up the undertray and screw the capscrews into the captive rivnuts. So if you want to use steel rivnuts above 6mm you may want to get the power tool ( not cheap!) I HAVE pulled up 6mm steel ones with a hand tool but its really hard work and, I suspect, could break the hand tool eventually. there are two kinds - aluminium and steel - you can pull up the ally ones up to the 6mm ( internal thread) size easily. Some thoughts ( sorry if a bit 'jack and Jill' Rivnuts are great, I didnt know they existed until I had done half my car with either bolts behind panels - unreachable after assembly or crude studs.

Sheet metal rivet nuts quotes