S-91771A121 4-40 x 9/16" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws
Stainless Steel Phillips Flat Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Exceptional corrosion resistance with passivated 18-8 stainless steel construction, ideal for harsh environments and long-term reliability.
- Superior holding power from fully threaded UNC coarse spacing, ensuring maximum grip and vibration resistance in assemblies.
- High tensile strength of 80,000 psi and Rockwell B80 hardness for dependable performance under mechanical stress.
- Precise 82° countersink angle allows for flush mounting, reducing protrusion and improving aesthetic finish.
- Reliable Class 2A thread fit guarantees consistent installation and compatibility with standard nuts and tapped holes.
- Convenient No. 1 Phillips drive enables efficient installation with common tools, reducing assembly time.
- Compliance with ASME B18.6.3, RoHS 3, and REACH ensures adherence to industry standards and environmental safety.
Professional Applications & Engineering Value
Engineered for demanding industrial settings, these 4-40 UNC flat head screws in passivated 18-8 stainless steel address common challenges like corrosion and mechanical failure. The fully threaded coarse design enhances load distribution, preventing loosening in high-vibration applications such as machinery, electronics, and automotive assemblies. The 82° countersink angle ensures a seamless fit, minimizing snag risks and improving airflow in compact designs. With a Rockwell B80 hardness and 80,000 psi tensile strength, they provide reliable fastening in structural components, reducing maintenance needs and downtime. Ideal for OEM and MRO use, these screws deliver consistent performance where precision and durability are critical.
Specification Summary & Compliance
This screw adheres to Class 2A thread fit per UNC standards, ensuring precise dimensional accuracy for reliable assembly. Manufactured in compliance with ASME B18.6.3 specifications, it meets rigorous engineering guidelines. Environmental and safety standards are upheld through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, confirming the absence of hazardous substances. The right-hand thread and fully threaded design support consistent performance across industrial applications.
