None of the insert plates I could buy for my old Sears/Craftsman 12" bandsaw fit very well so with my new printer I decided to give it a try.  This fits snugly and is tight around the key tab vs loose like the acrylic ones I had been buying.

Mine are printed in PLA, relatively low quality settings, 10% infill (there's almost none except in the raised inner lip) and haven't been put to the test, but seem like they'll do alright