deburring tool hanger

I have [this deburring tool](https://www.homedepot.com/p/Husky-Deburring-Tool-80-531-111/304583908) from Home Depot but it's too fat for some of my pen holders and didn't have any other way to be organized. So I printed a replacement end cap with 12mm threads for it. Success!

Note the scad in this is "some assembly needed"; it references [parkinbot's threading library](https://www.thingiverse.com/thing:1659079) and expects it to be named properly.