S-91251A297 1/4"-28 x 1 7/8" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure.
• Class 3A thread fit provides superior precision and tighter tolerances for secure, vibration-resistant connections in critical assemblies.
• Black-oxide surface treatment on alloy steel enhances corrosion resistance, extending service life in demanding industrial environments.
• Fine UNF threads offer improved load distribution and better clamping force compared to coarse threads, ideal for precision applications.
• Partially threaded design allows for precise positioning and reduced thread galling, simplifying installation in confined spaces.
• Hex socket drive with 3/16" drive size enables high-torque application and easy installation with standard tools, minimizing slippage.
• Rockwell C37 hardness ensures excellent wear resistance and durability, maintaining fastener integrity over repeated use.

Professional Applications & Engineering Value

Engineered for high-performance industrial fastening, these Black-Oxide Alloy Steel Socket Head Cap Screws address critical challenges in machinery, automotive, and aerospace sectors. The fine UNF threads (1/4"-28) and Class 3A fit provide superior vibration resistance and precise alignment, preventing loosening in dynamic applications. The black-oxide coating combats corrosion without compromising dimensional accuracy, making these screws ideal for environments exposed to moisture or chemicals. With a partially threaded shank, they facilitate exact placement in assemblies where full threading is unnecessary, reducing stress concentration. These features collectively enhance reliability in high-tensile applications, ensuring long-term operational safety and reduced maintenance costs.

Specification Summary & Compliance

This Socket Head Cap Screw adheres to Class 3A thread tolerances for precise fit and UNF fine thread standards (1/4"-28). Manufacturing complies with ASTM A574 specifications, ensuring consistent quality and mechanical properties. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for hazardous substances.