Oh yeah, nothing like learning the hard way. I made these for the bi-fold doors on the pantries in my kitchen - three doors need three knobs.
However... the plastic of the door knobs just didn't stand the heat so well.
And they turned out looking like rather sad mushrooms. No worries, I'll find another use for my three homeless flowers, but just in case you give this a whirl... don't put plastic knobs in your polymer oven!