Howdy all. I see lots of 'look at my finished magnetized 'jack' posts, but never a how to. As in every small little step. So, this is an attempt to do such a thing.
To start, you'll need to collect some supplies:
I chose two magnet sizes. One for the heads and the other for everything else.
Head magnets were 1/16" dia by 1/32" thick ($3 for 100)
Arm / Hand magnets were 1/8" dia by 3/32" thick ($0.12 ea)
Depending on just how big your magnets are, you will likely need to drill holes at least twice. Once with a smaller bit to make a pilot hole, and again with a drill the same diameter as the magnet. One of the easiest ways to check a drill's size compared to your magnet is to stick them on the flat end of the drill bit:
Drill too small - but good for drilling pilot holes
Drill too big
Drill perfect size
If you can't see the magnet in the picture above, that's good. It should look like an extension of the drill - they should be the same size.