What problems are you guys having with them? Maybe I've just not used mine enough, but my process has always been along the lines of:
1) Drill hole
2) put in rivnut
3)
4) Profit!!!
OK - given my usual OCD tenancies, it's not that simple. Between step 1 and 2 I take a baby (IE, 2mm x 7mm) square-edge file and file a "keyway" in the side of the hole I've just drilled. Reason being to give the rivnut itself something to squish into and key itself into. I read that this is what aircraft manufacturers do, as it stops the rivnut itself rotating in the hole when to do up or undo the bolt. However talking to people who do a lot more nutserting than I, they assure me that this is not a necessary step. I still do it anyway, see the above OCD comment.
I usually put a decent layer of paint down on the freshly drilled hole, and then another one over the set rivnut as well. The inserts I'm currently using are gal steel, so don't strictly need it, however I figure that in deforming them I'm potentially flaking off some of the coating, so it's worth the extra 20 mins that it takes the paint to dry.
Other than that, it's just a matter really of keeping the nutsert gun nice and perpendicular to the surface that you're setting the insert into, otherwise you run the risk of either stripping the mandrel or breaking it, as I have already done. This is easier said that done, especially on the bigger inserts when you're squeezing hard, and working on odd angles to start with. It requires a lot of concentration (well, for me it does). The breakthrough for me came when talking to the importer of the tool, who told me not to use too much pressure when using the gun to set the inserts - just use enough to stop the insert rotating. then when you tighten up the bolt into it, it will have the effect of squeezing down the insert tight, and it a much easier and safer way of achieving the same result. By putting so much pressure through the gun I was simply making it hard for myself, and risking damaging the tool.
What's other people's experiences?
Thanks!
Matto