S-91783A557 1/4"-28 x 1/2" ASME B18.6.3 Stainless Steel Round Head Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel construction and passivated finish, ideal for harsh industrial environments
• High tensile strength of 100,000 psi ensures reliable performance under heavy loads and vibration
• Precision Class 2A thread fit provides smooth assembly and consistent engagement in UNF fine-thread applications
• Fully threaded design maximizes grip length and load distribution across the entire fastener
• Rockwell B100 hardness offers excellent durability and resistance to wear during repeated use
• Standard slotted drive and rounded head profile enable easy installation with common tools while reducing surface protrusion
• Full compliance with ASME B18.6.3, RoHS 3, and REACH guarantees material safety and interchangeability in regulated industries

Professional Applications & Engineering Value

This 1/4"-28 UNF rounded head slotted screw delivers critical performance in demanding applications where corrosion resistance and mechanical strength are paramount. The combination of 18-8 Stainless Steel and a passivated finish provides exceptional protection against rust and chemical exposure, making it suitable for marine, food processing, and outdoor equipment. The fine UNF threads and Class 2A fit ensure precise, vibration-resistant fastening in machinery, electronic enclosures, and precision assemblies. Its fully threaded design allows for adjustable clamping force, while the rounded head minimizes snagging and improves safety in moving parts. Engineered to meet ASME B18.6.3 specifications, this screw offers reliable interchangeability and long-term service life in OEM and MRO operations.

Specification Summary & Compliance

This screw features a 1/4"-28 UNF thread with Class 2A tolerance for precise fit, manufactured to ASME B18.6.3 standards. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material traceability. The inch-system dimensions include a 0.472" head diameter and 1/2" length, with right-hand threading and fine thread spacing for secure fastening in industrial components.