I had a 1.375x0.19 inch magnet left over from another project. It was stuck to the storage shelves in my office, languishing. It is too large and powerful to use on its own so I whipped up a "push pin" so it could go on the fridge.
I highly encourage using epoxy, or another strong glue, to retain this in the pin. They're surprisingly strong, and prone to departing the pin at high speed if not glued. Superglue is not strong enough. Trust me.
TIANSE Green PLA Filament: https://amzn.to/2MUN4bw
Loctite E-20HP Hysol Epoxy: https://amzn.to/2J4AFQ2
Loctite "Epoxy Gun": https://amzn.to/2KZwS8y
Epoxy Nozzles: https://amzn.to/2KTYVWN