explains the classes and the manufacture of sprocket
subject to fewer chain engagements in a given time. For
wheels (called sprockets here). If you want more
severe service, cast steel or steel plate is preferred.
in-depth information, refer to the current edition of
The smaller sprockets of a drive are usually made
Machinery's Handbook.
of steel. With this material, the body of the sprocket can
be heat-treated to produce toughness for shock
CLASSES OF SPROCKETS
resistance, and the tooth surfaces can be hardened to
resist wear.
There are two classes of sprockets; commercial and
Stainless steel or bronze may be used for corrosion
precision. The choice is a matter of drive application
resistance; and formica, nylon, or other suitable plastic
judgment. Commercial sprockets are adequate for the
materials may be used for special applications.
usual moderate to slow speed commercial drive. When
you have a combination of extremely high speed and
MANUFACTURE OF SPROCKETS
high load, or when the drive involves fixed centers,
critical timing, register problems, or close clearance
Cast sprockets have cut teeth, and the rim, hub face,
more appropriate.
and bore are machined. The smaller sprockets are
generally cut from steel bar stock and are finished all
MATERIAL FOR SPROCKETS
over. Sprockets are often made from forgings or forged
bars, and the finish depends on specifications. Many
Cast iron is commonly used in large sprockets,
sprockets are made by welding a steel hub to a steel
especially in drives with large speed ratios. It is
plate. This process produces a one-piece sprocket of
adequate because the teeth of the larger sprockets are
14-30