I have been working on upgrades to my cupcake and after cleaning up bolts and nuts for the third or fourth time i decided i needed a magnet at hand at all times.

Print the ring Half twice and glue the halves together. Print the Magnet Donut and glue it to the top. Finally glue a magnet into the donut. Please note the parts may need some sanding and or a little dremel work. I had to increase the size of the inside of the donut a little.