This is a coin-slider trick like no other. The coin goes in one side as heads, and comes out the other side as tails! And there are other tricks that can be performed with this device. You can turn a penny into a quarter. You can make a quarter disappear. You can even mark a coin to “prove” to your audience that it is the same coin flipping over.

The secret is that there are two coins.  One of the coins is hidden inside the slider bar.  The hidden coin is revealed when the bar is slid through the flipper device.  Magnets are hidden in the flipper device and in the slider bar mechanism. The magnets also serve as a latch to prevent the coins from sliding when the slider bar is out of the device. Sliding the bar through the device unlocks the magnetic lock and moves the slider to hide the first coin and reveal the hidden coin.

The magnets used are 10x2 mm round magnets, which can be purchased from MakerWorld (CA016) or from Amazon.  A slightly smaller diameter magnet would possibly work also, but the thickness cannot exceed 2mm. A total of 6 magnets are used.

The slider bar parts are printed at a 0.12 mm layer height to allow multiple layers to be printed for the thin parts.  The outer flipper device can be printed at a standard 0.20 layer height to save time. The Yin-Yang symbol on top of the flipper device is hiding three magnets.  This part must be glued in place.

All of the magnets need to be installed at the same polar orientation. I recommend marking the top of each magnet as you pull it off the stack, then installing all the magnets with the mark facing up.

The slider bar consists of three parts. The internal coin holder has five holes in it.  The three small holes hold three magnets. The bottom of the slider bar has recessed holes under the magnets.  When the magnets fall into these holes the bar is locked and will not move. The top and the bottom should snap together without glue. Since all of our printers will be a little different, you may need to do some additional adjustments. If the pins will not fit into the holes, use a sharp blade to gently reem out the top edge of the hole to help the pin get started into the hole.

The outer flipper device has 3 recessed holes for magnets.  Place one magnet in each hole, maintaining the same polar orientation as the magnets in the slider bar. Glue the Yin-Yang emblem over the magnets so that they are hidden.

Please let me know if I need to adjust the dimensions to work with the 1 Euro coin. 

Enjoy the magic!

On 5/19/25 I re-uploaded the print profile with a very minor change to the depth of the magnet holes so that the latching mechanism will be more reliable.

Click here to see all of my magic tricks.