S-91286A121 1/4"-20 x 2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional Load-Bearing Capability – With 150,000 psi tensile strength and Grade 8 classification, this screw reliably handles extreme mechanical stresses in demanding environments.
• Superior Corrosion Resistance – Zinc-flake coating provides robust protection against rust and chemical exposure, extending service life in harsh industrial settings.
• Optimized Thread Engagement – 1/4"-20 UNC coarse threading ensures quick assembly and secure fastening, even in applications with vibration or dynamic loads.
• Precision Manufacturing – Class 2A thread fit guarantees consistent dimensional accuracy for reliable performance and interchangeability.
• Enhanced Durability – Rockwell C33 hardness delivers excellent wear resistance, maintaining fastener integrity through repeated use.
• Secure Drive Interface – External hex head design allows for high torque application with standard tools, preventing stripping during installation.
• Regulatory Compliance – Meets ASME B18.2.1, SAE J429, RoHS 3, and REACH standards, ensuring safety and environmental responsibility.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications where failure is not an option, this Grade 8 hex head screw combines high-strength steel construction with advanced zinc-flake coating to solve critical fastening challenges. The 1/4"-20 UNC coarse thread configuration provides superior resistance to vibration loosening in machinery, structural assemblies, and equipment subjected to dynamic stresses. Partially threaded design concentrates strength where needed most while allowing for precise clamp load distribution. These industrial hex head screws deliver reliable performance in construction, manufacturing, automotive, and heavy equipment applications where 150,000 psi tensile strength and consistent Rockwell C33 hardness prevent premature failure under extreme operational conditions.

Specification Summary & Compliance

Manufactured to precise Class 2A thread fit tolerances with 1/4"-20 UNC coarse threading and 2" length specification. Complies with ASME B18.2.1 and SAE J429 Grade 8 standards for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements, ensuring safe use across regulated industries.