Mechanix Illustrated, August 1964
"Build a Hypnotizing Harmonograph" by Keith A. Gourlay
The design of this Harmonograph drawing machine was probably influenced by the Lissajous Figure Drawing Machine described in Mathematical Models by Cundy and Rollett and other earlier unpatented pendulum drawing toys. This configuration is sometimes seen at scholastic science fairs. Reprints of this article have been widely distributed because they seem to turn up everywhere; such as in the files of school libraries and for sale on eBay (less than $8.00).
Design Critique: Legs aren't study enough, design a more rigidly braced table support; universal hinges between the Pen arms and the top of the pendulum rods are redundant, a "Pin & Cup" gimbal arraignment is adequate there; you really need something better that a ball point pen, these require too much pressure and create excessive friction.
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