This standard establishes a conformance test procedure for the performance of Nonmetallic Resistant Element Prevailing-Torque Screws (hereinafter called “REPT screw”), in nominal screw sizes No. 0 thru 1-1/2 in. While the requirements of this standard apply to Nonmetallic Resistant Element Screws, it is not the intent to preclude alternate types of screws which totally satisfy the requirements of this standard.

The prevailing-torque values given in this standard are conformance requirements for REPT screws and apply only to the combination of test conditions described in the performance test procedure (4.1). If the conditions of the actual service application differ from those of 4.1 (e.g., internally threaded hole in a different material, length of thread engagement, class of internal thread tolerance, speed of driving, different plating or coating on screw or mating part), the prevailing-torque values may vary. Such values can only be determined through testing the REPT screw in its specific application.

This standard is not concerned with dimensional features such as head styles, or with performance capabilities such as corrosion resistance, sealing, suitability for use in high or low temperatures, and/or consistency of torque-to-tension relationships during assembly. Such features and properties are covered in other standards and specifications and must be referenced when specifying a REPT screw to assure that all of the service conditions of the particular engineering application are properly met.

(Note: The application of some nonmetallic elements requires heating of an isolated area in the screw thread to approximately 600°F which may have an adverse effect on the mechanical properties of some products.)