IFI-525, Test Procedure for the Performance of Metric Adhesive Coated Prevailing-Torque Screws


Issued 1982; Revised 2007, Reaffirmed 2012



This standard establishes a conformance test procedure for the performance of metric adhesive coated prevailing-torque screws in nominal thread diameters M3 thru M20 inclusive. Torque values given in this standard are conformance requirements for adhesive coated prevailing-torque screws and apply only to the combination of test conditions described in the performance test procedure (Para. 5.1). If the conditions of the actual service application differ from those of Para. 5.1 (e.g., length of thread engagement, class of internal thread tolerance, different coating on screw or mating part) the torque values may differ. Such values can only be determined through testing the prevailing-torque screw in its actual assembly. This standard is not concerned with dimensional features such as head styles, or with other mechanical or performance capabilities such as strength properties, 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 an adhesive coated prevailing torque screw to ensure that all of the service conditions of the particular engineering application are properly met.