Abracadabra! Perform a magic coin piercing trick and amaze your family and friends. The eight solid pins pierce the solid coin eight times yet the coin comes back out of the container undamaged!

See the demo video at http://youtu.be/96b9ElucVW0 .

This project is sure to amaze your kids and help reassure your spouse that the 3D printer is a true household asset!

Also see Thing 25344, http://www.thingiverse.com/thing:25344.

Enjoy!

11 June 2012: Add missing OpenSCAD source file 11 June 2012: Ran the bottom piece through Netfabb 14 June 2012: Determined cause of problems for Slic3r; uploaded new top & bottom .stl file and new .scad file

Download the three .stl files, slice them, and print them. For maximum impact, print the coin and pins a contrasting color from that used for the top and bottom of the enclosure. Note that I sliced using 100% fill and 4 shells. The pins may print better with a raft.

You can use the supplied OpenSCAD file to regenerate the container and pins to your specifications. For example, to a size which will work with your local currency.

To perform the trick,

1. Let your audience inspect the coin and pins. Check your sleeves, etc., etc.
2. Place the coin into the bottom of the container.
3. Place the top cover over the bottom. The two pieces have alignment tabs to ensure correct orientation of the pin holes between the top and bottom.
4. Begin by "piercing" the coin with a pin through one of the outermost four holes. Do NOT start with any of the four inner holes. By using one of the outer holes, the coin is tipped upwards and out of the way of the pins.
5. Place the remaining seven pins through the remaining seven holes.
6. Show your audience that the pins move: push one from the bottom and see the pin's head rise.
7. Remove the pins. Unlike in the video, things will be a little quieter if you remove the outer pins first: that way the coin only shifts down a little at a time. If you make the last pin an outer pin, then the coin will have farther to drop.
8. Give a gentle magic "tap" and/or shake, maybe saying "presto" or "abracadabra" at the same time. This is really to make sure that the coin has dropped back down.
9. Re-open the container, showing the audience that the coin is still there and undamaged with no holes.