Inside the Strange World of Coin Shrinking

By Alice Hill
RealTechNews

We like to mix it up a little here at RealTechNews - sometimes we toss in a little auto tech coverage, other times we look at flying cars and strange medieval weaponry (like my favorite, the trebuchet) so today we’re going to put on our lab coats and explore the odd practice of shrinking coins, or to be more particular, the art of Quarter Shrinking.

Theory of Operation:

The Quarter Shrinker uses a technique called high velocity electromagnetic metal forming, or “Magneforming”. This technique was originally developed by the aerospace industry in conjunction with NASA, and has been popularized by Aerovox, Grumman, and Maxwell. It involves quickly discharging a high energy capacitor bank through a work coil to generate a very powerful and rapidly changing electromagnetic field which then “forms” the metal to be fabricated. While it works best with metals of relatively high electrical conductivity such as copper or aluminum alloys, it will work to a more limited extent with many poorer conducting metals and alloys such as steel or nickel.

To shrink coins I charge up a large capacitor bank which consists of a number of large capacitors, each weighing about 165 pounds (each about 30″ x 14″ x 8″). A High Voltage relay is used to connect the capacitor bank to either a high voltage DC charging supply, or to a bank of high power resistors. A 15,000 Volt 60 milliampere high voltage transformer and a set of 40 kV rectifiers make up the DC charging supply for the capacitor bank. The primary of the transformer can be overdriven to 140 volts via a variable autotransformer in order to speed up the charging process. The electrical energy stored in the capacitor bank is proportional to the square of the stored voltage, and the degree of “shrinking” force is directly proportional to the capacitor bank’s energy.

But Isn’t Mutilating Money a Federal Offense?
So Who Invented this Crazy Device?
Enter Complete World of Quarter Shrinking Here Source: Stoneridge Engineering