S-93791A407 4-40 x 1/4" ASME B18.3 Stainless Steel Hex Drive Flat Head Screws
Stainless Steel Hex Drive 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
- Superior corrosion resistance with 18-8 stainless steel construction and black-oxide passivated finish, ideal for harsh industrial environments
- Exceptional tensile strength rated at 70,000 psi for reliable, high-stress fastening applications
- Precision Class 3A thread fit ensures consistent engagement and vibration resistance in assemblies
- 82° countersink angle provides flush mounting with standard countersunk holes for clean, professional finishes
- Hex drive design allows for secure tool engagement and efficient installation in confined spaces
- Full threading along the 1/4" length maximizes grip strength and load distribution
- Compliance with ASME B18.3, RoHS 3, and REACH guarantees quality, safety, and environmental standards
Professional Applications & Engineering Value
These 4-40 UNC flat head screws are engineered to address critical fastening challenges in demanding industrial settings. The 18-8 stainless steel material, combined with a black-oxide passivated finish, provides excellent resistance to corrosion and oxidation, extending service life in humid or chemically aggressive environments. The Class 3A thread fit and coarse UNC threading ensure quick assembly and reduced cross-threading risks, while the flat head with 82° countersink allows for seamless surface integration in machinery, electronics, and automotive components. With a Rockwell B55 hardness and 70,000 psi tensile strength, these screws maintain integrity under vibration and dynamic loads, making them ideal for precision equipment, enclosures, and structural applications where reliability is paramount.
Specification Summary & Compliance
This product features a 4-40 UNC coarse thread with Class 3A fit for high precision and consistent performance. It meets ASME B18.3 specifications for dimensional accuracy and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material restrictions adherence. The screw is fully threaded, with a length of 1/4", head diameter of 0.255", and right-hand thread direction, manufactured to deliver reliable fastening in industrial applications.
