MOLDING TOLERANCES Often we receive prints detailed to tolerances which are unrealistic for the applications. The tighter the tolerances the higher the cost of the part. Keep in mind that on non-critical dimensions it's best to consult us on what is practical for molding and optimum part cost. If there is a requirement for very close tolerances on certain dimensions, we can achieve them either by proper sizing of the tooling or by secondary machining steps after the part is made. Unlike metals,often urethanes have a very high coefficient of thermal expansion (1.0 - 1.5 x 10-4/in./in./oF.  If a part is made to a +/- .005 inch tolerance, as measured at 75oF (24oC), it could be out of tolerance at 0oF (-17oC) 150oF (66oC). Here are some guidelines for "as molded" tolerances: Typical "As Cast" Tolerances 0-1 in. (0-25) +/- .005 (+/- .1) 1 in. - 36 in. (25 - 915) +/- 0.5% 36 in.+ (915+) +/- 0.7% NEXT: Physical Constants