S-90211A303 3/8"-16 x 2 1/2" SAE J429 Left-Hand Threaded High-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with Grade 8 classification and 150,000 PSI tensile strength for reliable performance in high-stress applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in demanding industrial environments
• Precise thread engagement with Class 3A thread fit ensuring secure fastening and vibration resistance in left-hand applications
• Optimized torque transmission through the 9/16" external hex head design for efficient installation with standard tools
• Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated stress cycles
• Reliable reverse-threading functionality with left-hand UNC coarse threads for specialized mechanical systems requiring counter-rotational security
• Full compliance assurance with SAE J429 specifications, guaranteeing consistent quality and performance standards

Professional Applications & Engineering Value

This Grade 8 steel hex head screw delivers critical engineering solutions where reverse-threading requirements meet extreme mechanical demands. The left-hand UNC coarse threading provides essential counter-rotational security in machinery where standard right-hand threads would loosen under operational forces. The zinc yellow-chromate plating creates a robust barrier against corrosion, significantly extending service life in harsh industrial environments including manufacturing equipment, heavy machinery, and automotive applications. With full threading along the 2½" length, this fastener ensures maximum engagement strength while the external hex drive facilitates secure installation with standard tools. The combination of 150,000 PSI tensile strength and Rockwell C33 hardness makes this screw ideal for structural applications requiring both high clamp load capacity and fatigue resistance.

Specification Summary & Compliance

This high-strength hex head screw features precise 3/8"-16 UNC coarse threading with Class 3A thread fit tolerance for optimal engagement. The fastener maintains dimensional accuracy per inch system specifications with 2½" length and 9/16" hex head width. Manufacturing and performance characteristics fully comply with SAE J429 Grade 8 standards, ensuring consistent quality and reliability for industrial applications. The zinc yellow-chromate plating provides environmental protection while meeting industry requirements for corrosion resistance in demanding operating conditions.