I found it! There is an extensive Popular Science article, "How Coin
Machines Detect Phony Money" from March of 1962 that covers the
"Philadelphia Quarter" or "Air Force Special". The penny was simply
jammed into the spark plug gasket.
I've plugged the link in here, but it's pretty long, so you will
probably have to reassemble it yourself:
http://books.google.com/books?id=OyE...page&q&f=false


Interesting to note: Within that pdf of the whole magazine, there's a
one page ad for "American Machine and Tools". It shows an 8" tilting
arbor table saw for $9.95. It's all there but the motor. I bought one
at about that time and used it for many, many years, with a 1/3 hp
washing machine motor that I had to reverse in a rather unconventional way.

Pete Stanaitis
-----------------------

spaco wrote:
I seem to remember that, during wwII, the guys at some eastern US air
force base found that they could solder a penny or a nickel into the
center of a spark plug compression washer and then use it in a vending
machine. The idea worked so well that it created a major problem for
vending machine makers and operators of the day.

Does anyone remember more details?

Pete Stanaitis