Mine failed as well.
I fabricated a couple of penny washers from a bit of 2mm stainless steel sheet. I had intended to make 4, but the usual loveable
characteristics of s/s meant that it work-hardened enough to trash the hole saw before the third was complete.
I presume the sheet was annealed, since the washers became a bit conical. I have reversed them a few times, in the hope that work-hardening will set in eventually. After 27 000 miles they survive, but don't seem to have stiffened yet. I think it's called travelling hopefully
.