This section is from the book "The Boy Mechanic Vol. 1", by Popular Mechanics Co.. Also available from Amazon: 700 Things for Boys to Do.
The accompanying photographs show the construction of a very unique electric motor, the parts consisting of the frame from an old bicycle pedal wrapped with insulated wire to make the armature and three permanent magnets taken from an old telephone magneto. The pedal, being ball bearing, rotated with very little friction and at a surprisingly high rate of speed.
The Motor Complete
The dust cap on the end of the pedal was removed and a battery connection, having quite a length of threads, was soldered to it as shown in the photograph. The flanges were removed from an ordinary spool and two strips of brass fastened on its circumference for the commutator. The spool was held in position by a small binding post nut. The shape of this nut made a good pulley for a cord belt. --Contributed by John Shahan, Attalla, Ala.
Illustration: Commutator Parts
 
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