Wanted to share what I found to rivet lamp covers to plastics while swapping old plastics with new . I found split rivets , 3mm shaft width and 5 or 6 mm long . Just push through using the old washer and took a punch and tapped the split to flare them out a good bit, then flipped the punch owner and taped the flat end of punch against the rivet to flatten a tad more . No expensive tool needed to put on a new set of plastics with rivet on lamp domes.
Hope this helps someone , and I'm not repeating someone else's post here,