S-91781A115 4-40 x 1" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish for long-lasting performance in harsh environments
• High tensile strength of 80,000 psi ensures reliable fastening under heavy loads and vibration
• Full threading along the 1" length provides maximum grip and uniform stress distribution
• Class 2A thread fit with UNC coarse threads enables quick assembly and reduces cross-threading risks
• Standard 82° countersink angle allows for flush mounting in precision applications
• Rockwell B80 hardness maintains structural integrity against wear and deformation
• Compliance with ASME B18.6.3, RoHS 3, and REACH guarantees quality and environmental safety for industrial use

Professional Applications & Engineering Value

These 4-40 UNC flat head slotted screws are engineered to address critical fastening challenges in industrial settings. The 18-8 stainless steel material combined with a passivated finish provides exceptional resistance to oxidation and chemical exposure, making them ideal for machinery, electronics, and outdoor equipment. The coarse UNC thread and Class 2A fit ensure rapid installation with minimal tooling, reducing assembly time while maintaining precision. With full threading and a standard flat head profile, they deliver secure, flush fits in countersunk holes, preventing protrusion and enhancing safety in moving parts. These screws are trusted in applications demanding high tensile strength and durability, from automotive assemblies to aerospace components, where reliability under stress is non-negotiable.

Specification Summary & Compliance

This product adheres to Class 2A thread fit per UNC standards, ensuring dimensional accuracy for consistent performance. Manufacturing follows ASME B18.6.3 specifications for flat head slotted screws, with a 1" length, 4-40 thread size, and right-hand thread direction. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) confirms environmental safety, free from hazardous substances. The passivated finish and stainless steel composition support use in regulated industries, providing a reliable, standards-based solution for professional fastening needs.