S-90409A170 1/2"-20 x 4" IFI 111, SAE J429 High-Strength Grade 8 Steel Flanged Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional strength for demanding applications with Grade 8 steel construction and a tensile strength of 150,000 psi, ensuring reliable performance under high stress.
• Superior wear and deformation resistance due to Rockwell C32 hardness, providing long-term durability in harsh industrial environments.
• Secure and precise fastening with UNF fine threading and Class 2A thread fit, offering excellent vibration resistance and reduced risk of loosening.
• Enhanced load distribution and stability from the integrated flange, eliminating the need for a separate washer and speeding up assembly.
• Easy installation and removal with a standard 3/4" external hex head, compatible with common wrenches for efficient maintenance.
• Reliable performance in high-stress scenarios thanks to partial threading, which concentrates strength where it's needed most.
• Compliance with major industry standards including SAE J429 and IFI 111, ensuring consistent quality and safety.

Professional Applications & Engineering Value

This Grade 8 steel hex head screw is engineered to address critical challenges in heavy machinery, construction, and automotive assemblies where failure is not an option. Its UNF fine thread design provides superior resistance to vibrational loosening compared to coarse threads, making it ideal for dynamic load conditions. The flanged head distributes clamping force over a wider area, reducing surface pressure and preventing damage to connected materials. With a 150,000 psi tensile strength and Rockwell C32 hardness, it withstands extreme forces and abrasion, ensuring long service life in demanding environments like engine mounts, structural frames, and industrial equipment. The partially threaded shank offers optimized grip length, minimizing stress concentrations and enhancing fatigue resistance for reliable, maintenance-free operation.

Specification Summary & Compliance

This screw features a 1/2"-20 UNF fine thread with Class 2A thread fit for precise tolerance, ensuring consistent engagement and performance. It meets IFI 111 / SAE J429 specifications for material and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing it is free from hazardous substances and safe for use in various industrial and international markets.