Is attaching bearings with pop-rivets + washers stable enough for a competition robot?
If the bearing block does not have a lot of direct load or vibration , yes you can use them. We have one team that swears by them and a bunch that avoid them.
But be careful with these pop rivets on many other applications, as they do not hold as tight. But they are lighter than a screw + nylock nut combination. So if weight is critical, these can save a bunch of weight for you. Just pile up 20 screws and nylock nuts in your hand and see how much they weigh.
Would pop-rivets suffice for a drive?
Most of our teams usually use pop rivets on their drive base, even in competition. On other assemblies, some of the students like them for prototyping, then change to screws and nylocks when the assembly is proven. A work of caution: keps nuts will not lock properly with a bearing rivet, you must use a nylock.
Yes. This is one of the typical places. Lifts and manipulators are the ones that have more impact and shocks.
Pop rivets definitely have their applications. At first I was weary of them, but as long as you use fresh ones, and all 4 prongs split apart, it will hold well. You must insert them into the metal side, or put 2 white washers on the end to fill up the slack. They are useful in tight clearance applications, because they do not “loosen” and they are lower profile than .5" screw.