Review on SAE Rivet Nut Kit, 40 Pcs Heavy Duty Zinc Plated Carbon Steel Flat Head Insert Knurled Body UNC 5/16"-18 by Rob Kerr

For those who have used these before or know how to use them you'll find these are your average quality steel rivnuts. They compress evenly and hold well. (For my uses) They give you more of your most common sizes and less of the uncommon, which is refreshing since usually it's the opposite. If you know what you're doing you can stop reading now. For those unfamiliar with the greatest thing since sliced bread. These are basically threaded rivets So it you ever need to put a screw/bolt into a thin piece of material where the underside is unaccessible (or even if it is) you've found the solution.I first used these to attach an upgraded trolling motor to my Xpress Bass boat. The new holes didn;t align with the old ones and you couldn't access underneath without some serious disassembly. So I marked the holes, took the included mounting bolts, matched them to the correct mandrel and rivnut, drill the correct sized hole (very crucial) and had six rivnuts in and trolling motor screwed down in about 30minutes. The other applications are endless. I guess I need to back up. In order to use rivnuts you'll need 1) a rivnut compression tool. 2) A properly sized rivnut to fit the screw/bolt size needed and the thickness of the material it's going into. 3) A different sized mandrel for each differently sized rivnut and 4) A very complete set of drill bits for the proper hole size. You can buy a kit with everything but the drill bits for $36-$80 (see photos) 1) Put the correct mandrel on your rivnut tool, in this case 1/4-20 2) Open up the arms of the tool and spin the 1/4-20 rivnut on 3) Insert rivnut into the properly drilled hole, holding the tool perpendicular, push down and close the arms (not pictured) 4) Unscrew the tool from rivnut You can see the collar that is formed when the rivnnut is compressed and that's it's not much wider than the head of the rivnut. So the properly sized hole IMO is the most critical aspect of this. Most rivnuts failures I've seen are from holes that are too big, not enough material is grabbed when the rivnut is compressed and it will ultimately come loose. Once a rivnut is set you should never be able to move it side to side in a properly sized hole. There are reference charts all over the internet with corresponding drill bit sizes for every rivnut imaginable. Decent combo set for a decent price. If you want to upgrade or are putting these in a corrosive environment I'd highly suggest the stainless steel rivnuts. But these will do just fine for most applications.