S-90409A165 1/2"-20 x 2 1/4" IFI 111, SAE J429 High-Strength Grade 8 Steel Flanged Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior hardness (Rockwell C32) provides excellent resistance to wear and deformation, extending service life in demanding environments.
• Flange design eliminates the need for a separate washer, simplifying installation and providing a larger bearing surface for improved load distribution.
• Precise Class 2A thread fit on the UNF fine thread ensures smooth assembly and a secure, vibration-resistant connection.
• Grade 8 steel material offers outstanding strength-to-weight ratio, ideal for critical structural and machinery assemblies.
• External hex drive allows for high-torque installation with common tools, facilitating efficient maintenance and assembly.
• Partial threading provides an unthreaded shank for enhanced shear strength, making it suitable for pinned or precision-aligned connections.

Professional Applications & Engineering Value

This Grade 8 steel hex head screw is engineered to solve critical challenges in heavy machinery, automotive, and construction sectors. Its high tensile strength and Rockwell C32 hardness prevent stripping and fatigue under dynamic loads, while the flange distributes clamping force to protect soft materials and prevent loosening. The 1/2"-20 UNF fine thread and Class 2A fit deliver superior vibration resistance and precise engagement in components requiring fine adjustment. This combination of a partially threaded design and robust external hex drive makes it an optimal choice for demanding industrial applications where reliability and durability are non-negotiable.

Specification Summary & Compliance

This screw adheres to stringent dimensional and performance standards, including a Class 2A thread fit for consistent assembly and UNF fine thread specifications. It is manufactured to meet IFI 111 / SAE J429 for Grade 8 mechanical properties, ensuring traceability and quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming it is free from hazardous substances for safe use in global markets.