3D Printed Knife Sharpener. Upgrade your mug!

Print this and attach it to the bottom of a ceramic mug. If your mug is slightly smaller, wrap it with some electrical tape.
It holds a knife at a 20 degree angle so that it gets honed by the ring of unglazed ceramic on the mug.
Have fun with it! Please feel free to add to it and improve.

Check out the youtube video at:
http://www.youtube.com/watch?v=RVkwNF0TF3s

I also have an instructable!
http://www.instructables.com/id/Knife-Sharpener-Upgrade-for-your-Mug/