Good point. I closed the top fully then opened it, stopping quickly once the first fold of the canvas top gave maximum access from below and above. Most of the broken rivet removal was squeezing and drilled slowly from below at an awkward angle taking a little material at a time. Once I broke away the expanded portion of the rivet, I tapped it up carefully with a nail set, being careful not to puncture the canvas.Did you have to remove anything to access it and drill?
The first time it happened I recall trying to push down on the rivet but access from above/outside the top was too tight