S-90402A120 4-40 x 1" ASME B18.13 Steel Pan Head Phillips Screws with External-Tooth Lock Washer
Steel Pan Head Phillips Screws with External-Tooth Lock Washer
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Washer & Nut
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Superior vibration resistance with an integrated external-tooth lock washer that maintains clamp force in high-motion environments
- Enhanced corrosion protection through zinc-plated steel construction, extending service life in harsh conditions
- High mechanical strength with 60,000 psi tensile strength and Rockwell B69 hardness for reliable load-bearing performance
- Secure and precise fastening with Class 2A thread fit and UNC coarse threads for easy alignment and reduced cross-threading risk
- Full-thread engagement along the entire 1" length ensures maximum grip and distribution of stress
- Quick installation using a standard No. 1 Phillips drive and rounded pan head design
- Regulatory compliance meets ASME B18.13 specifications and environmental standards including RoHS 3 and REACH
Professional Applications & Engineering Value
This 4-40 UNC zinc-plated steel pan head screw with lock washer is engineered to address critical challenges in industrial assembly, such as loosening under vibration and exposure to corrosive elements. The combination of a fully threaded design and coarse UNC threads ensures rapid installation and robust holding power in materials like sheet metal, plastics, and assembled components. The external-tooth lock washer bites into both the fastener and surface, providing lasting resistance to rotational forces in machinery, automotive subsystems, and electronic enclosures. With a zinc-plated finish, it offers an effective barrier against oxidation and moisture, making it suitable for outdoor equipment, HVAC systems, and production lines where durability and compliance with ASME B18.13 are non-negotiable.
Specification Summary & Compliance
This screw features a Class 2A thread fit with UNC coarse threading and right-hand direction, ensuring dimensional accuracy per industrial standards. It is manufactured in compliance with ASME B18.13 and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming its suitability for global supply chains and sensitive applications.
