S-92949A851 1/4"-28 x 4" ASME B18.3, ASTM F879 Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments.
• Exceptional holding power from a high 70,000 psi tensile strength, ensuring reliable and durable fastening in demanding applications.
• Precise, secure thread engagement with a Class 3A thread fit and UNF fine thread profile, minimizing the risk of loosening under vibration.
• Optimized for high-torque installation via the 5/32" hex drive, providing a secure grip and reducing the risk of tool slippage and head stripping.
• Versatile fully threaded design allows for maximum adjustability and consistent clamping force along the entire 4-inch length.
• Enhanced durability with a Rockwell B55 hardness, offering excellent resistance to wear and deformation.
• Guaranteed material safety and compliance, meeting RoHS 3 and REACH standards for use in regulated industries.

Professional Applications & Engineering Value

This 1/4"-28 UNF screw is engineered to solve critical fastening challenges in industrial settings. The combination of 18-8 stainless steel and a passivated finish provides a robust defense against corrosion, making it a reliable choice for machinery, marine equipment, and chemical processing applications where exposure to moisture and aggressive agents is a concern. The Class 3A thread fit and fine thread spacing ensure a tight, precise fit that is highly resistant to vibrational loosening, a common failure point in dynamic systems. The rounded head with a hex drive offers a low-profile, flush finish while enabling high torque application, streamlining assembly and enhancing the aesthetic and functional integrity of the final product.

Specification Summary & Compliance

This screw features a 1/4"-28 UNF thread with a precision Class 3A thread fit. It is manufactured in compliance with the ASME B18.3 specification ASTM F879. The product is also confirmed to be RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, ensuring it adheres to strict environmental and safety regulations for hazardous substances.