S-91205A648 3/8"-16 x 3 1/2" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with a permanent Nylon Patch thread locker that maintains integrity across a wide temperature range from -70° to 250°F, preventing loosening in dynamic environments.
• Exceptional tensile strength rated at 170,000 psi, providing reliable load-bearing capacity for high-stress industrial applications.
• Superior corrosion protection through Black-Oxide coating on Alloy Steel, enhancing durability and lifespan in harsh operating conditions.
• Precise thread engagement with UNC Class 3A coarse threads ensuring easy alignment and secure fastening in demanding assemblies.
• Optimized drive efficiency featuring a 5/16" hex socket head for high torque application without stripping, reducing installation time and tool wear.
• Controlled thread distribution via partially threaded design, concentrating grip where needed and minimizing material stress.
• Consistent hardness performance at Rockwell C37, offering resistance to deformation under repeated loads and impacts.

Professional Applications & Engineering Value

Engineered for rigorous industrial settings, this Socket Head Cap Screw combines Black-Oxide Alloy Steel with a Nylon Patch thread locker to address critical challenges like vibration-induced failure and thermal cycling. The UNC coarse thread design facilitates quick assembly in metals and plastics, reducing labor costs while the partially threaded configuration prevents over-tightening and distributes clamping force effectively. Ideal for machinery, automotive, and heavy equipment, it ensures long-term reliability in applications exposed to extreme temperatures and dynamic stresses, backed by high tensile strength and corrosion resistance.

Specification Summary & Compliance

This screw adheres to Class 3A thread fit for precise dimensional accuracy under ASME B18.3 and ASTM A574 specifications. It meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance for environmental safety, with threading conforming to UNC coarse spacing standards in the inch system. The thread locker temperature range of -70° to 250°F ensures performance stability across varied operational conditions.