IFI-555, Test Procedure for the Performance of Nonmetallic Resistant Element Prevailing-Torque Nuts (Metric Series)


Issued 2002; Revised 2005



This standard establishes a conformance test procedure for metric nonmetallic resistant element prevailing-torque nuts with specified prevailing-torque requirements, in nominal sizes M4 thru M20 intended for application temperatures of – 45°C to 120°C. Both partial (less than 360°) and full circumference (360°) element designs are included. It does not include nuts with adhesive coated threads which are included in IFI-560 or top insert two piece construction nuts which are included in ASME B18.16.1M, B18.16.2M and B18.16.3M.