S-91781A133 5-40 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, ideal for harsh or humid environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Precision thread engagement through Class 2A thread fit and coarse UNC threading, ensuring secure fastening and vibration resistance
• Streamlined flush installation with standard 82° countersink angle and flat head design for smooth, unobtrusive surfaces
• Broad industrial compatibility by meeting ASME B18.6.3 specifications and full 1" threading for versatile application use
• Enhanced safety compliance with RoHS 3 and REACH regulations, ensuring environmental and workplace safety standards
• Easy manual installation via slotted drive style, allowing quick assembly with standard screwdrivers

Professional Applications & Engineering Value

This 5-40 UNC flat head screw in 18-8 stainless steel addresses critical industrial challenges where corrosion resistance and structural integrity are paramount. The passivated finish significantly enhances surface durability, preventing oxidation in chemical exposure or marine settings. Its fully threaded coarse UNC design provides maximum grip in soft materials and plastics, reducing stripping risks while the 82° countersink ensures seamless flush mounting in precision assemblies. Engineers value its 80,000 psi tensile strength for securing components in machinery, electronics, and automotive systems where vibration loosening is a concern. The slotted drive offers maintenance flexibility in confined spaces, making it indispensable for OEM manufacturing and field service applications requiring dependable, long-term fastening solutions.

Specification Summary & Compliance

Manufactured to ASME B18.6.3 standards, this screw maintains Class 2A thread fit tolerances for consistent mating with nuts and threaded holes. The UNC coarse thread (5-40) with right-hand direction and full 1" length ensures dimensional accuracy across batches. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) confirms adherence to hazardous substance restrictions, supporting sustainable procurement in regulated industries.