Magnet Insertion Tools

I use a lot of [3mm (diameter) x 3mm (height) cylindrical rare earth magnets](http://www.gaussboys.com/store/index.php/magnet-shapes/cylinders/c0303.html) to hold 3d-printed puzzles and models together. The magnets can be hard to work with-- they are too small to comfortably grip, and it often takes some force to get them to fit into the holes on the model.

These tools solve the problem:

* include a 3.2 mm (dia) x 3.2 mm (height) cylindrical recess in your CAD model
* load the + or - tool with a magnet (the correct orientation will stick)
* add a little [JB Weld](http://www.amazon.com/J-B-Weld-8265S-Original-Reinforced/dp/B0006O1ICE) epoxy to keep the magnets in place for the long run
* insert magnet into your model using the comfy handle
* done!

This tool was developed as part of the project `Motivating First-Year Calculus with Robotics' supported by the National Science Foundation under [DUE-12-45540](http://www.nsf.gov/awardsearch/showAward?AWD_ID=1245540&Historic