Standard Height Steel Hex Nut with Nylon insert for locking. On the 364/365 series nylon insert nuts, nylon creates positive locking through multiple uses. Visually inspect the locking area for wear and replace the nut when you feel the resistance starting to relax. Thread Size & Pitch = 7/16 - 20. Hex Size = 5/8". Nut Height = 29/64". The temperature rating for this nut is 250 degrees Fahrenheit. The UTS of this nut is 125Ksi (862Mpa).