So I was ripping a 20 foot sitka spruce plank to size for my mast. I set up things as usual, put the wood up on scrap pieces of wood, on top of metal stands.
The trick is to set the saw blade to cut the spruce, and cut a little into the scrap, but not all the way through to the metal stands.
I remember thinking ah these glasses will do, then changing my mind and putting on my safety glasses.
So I started the rip cut, and then there was a sudden unpleasant noise, kind of like the teeth on a carbide tipped wood blade shattering as they lost the battle against the metal stand. (The metal stand didn't come out looking pretty either)
I'd forgotten to set the depth of cut.
Total damage was one carbide blade, a damaged stand, and a few cut's on my hand where bit's of carbide had made passing glances.
Could have been worse.
The glasses were un-marked. But it did serve as a reminder that they are not optional when working with things that spin in the thousands of rpm.