Hex Socket Set Screws — Including Nylon and Brass Tips — Are ALWAYS 3A per IFI
The Critical Difference Between 2A and 3A Threads
Thread class defines how tightly a fastener fits with its mating part—and that detail makes or breaks product integrity. Class 3A threads provide the secure, precision fit required for hex socket set screws. Yet more often, we’re seeing 2A threads substituted where 3A is specified—a serious quality risk that can compromise alignment, preload and long-term performance.