S-91286A143 1/4"-28 x 1 3/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 PSI tensile strength and Grade 8 classification for reliable performance in high-stress applications.
• Superior corrosion resistance provided by zinc-flake coating, extending service life in harsh industrial environments.
• Optimized torque transmission through external hex drive design, ensuring secure installation and preventing tool slippage.
• Precise thread engagement with UNF fine threading (1/4"-28) and Class 2A fit, delivering vibration resistance and secure fastening.
• Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated loads and impacts.
• Versatile partial threading allowing unthreaded shank sections for shear strength where full threading isn't required.
• Regulatory compliance assurance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for quality and environmental safety.

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers critical engineering solutions where high-strength steel fasteners must withstand extreme mechanical stresses. The zinc-flake coated surface provides superior corrosion protection compared to standard platings, making it ideal for automotive assemblies, heavy machinery, and construction equipment exposed to weather or chemicals. The 1/4"-28 UNF fine thread configuration ensures tighter sealing and better vibration resistance than coarse threads, while the external hex drive enables high-torque installation without cam-out risks. Partially threaded design offers optimal clamp load distribution, preventing joint loosening in dynamic load applications. These industrial hex screws solve common failure points in critical connections, providing reliable performance where fastener integrity is non-negotiable.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance ensuring consistent engagement. Thread specification follows UNF fine thread standards (1/4"-28) with minimum thread length of 3/4". Complies with ASME B18.2.1 and SAE J429 specifications for hex head screws. Meets environmental regulations including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) standards regarding hazardous substances.