The Precision Machined Products Association’s Designer’s Guide is intended for use by those who prepare drawings of precision machined parts.

Too often drawings do not have all the information needed to produce the piece described. This Guide is aimed at eliminating "silent" prints by showing what has to be specified and how it should be specified on the drawing.

This Guide calls attention to the characteristics on a part which, if clearly specified on the drawing, will eliminate confusion, arguments, and rejected production.

This Guide is not intended to teach anyone how to draw blueprints, but will point out where part drawings all too often are vague. One safe rule to follow is — leave nothing to chance or interpretation. Determine what is needed; then relay that information to your supplier by preparing a complete drawing. It will be mutually beneficial.

Note: The dimensioning and tolerancing practices used in this Guide follow the principles of ANSI/ASME Y14.5M, Dimensioning and Tolerancing. The latest revision of this standard, as well as other ANSI/ASME standards mentioned in this document, can be obtained from the American National Standards Institute.