S-90403A107 4-40 x 5/16" ASME B18.13 Steel Pan Head Phillips Screws with Internal-Tooth Lock Washer
Steel Pan Head Phillips Screws with Internal-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 thanks to the integrated internal-tooth lock washer that prevents loosening under dynamic loads
- Enhanced corrosion protection with zinc-plated steel construction, extending service life in harsh industrial environments
- High tensile strength of 60,000 psi ensures reliable fastening in demanding applications without failure
- Excellent thread engagement with Class 2A coarse UNC threads for quick assembly and reduced cross-threading risks
- Optimized drive efficiency through the Phillips No. 1 drive, providing secure torque transfer and reduced cam-out
- Full threading along the 5/16" length allows for maximum adjustability and holding power across the entire fastener
- Compliance with ASME B18.13, RoHS 3, and REACH guarantees consistent quality and environmental safety for global supply chains
Professional Applications & Engineering Value
These 4-40 UNC zinc-plated steel rounded head screws with internal-tooth lock washers are engineered to address critical challenges in industrial assembly, such as vibration-induced loosening and corrosion in exposed environments. The coarse thread design and Class 2A thread fit ensure rapid, reliable installation in metal, plastic, and composite materials, reducing assembly time and improving production throughput. The combination of 60,000 psi tensile strength and Rockwell B69 hardness provides durable fastening for machinery, electronics, and automotive components, where consistent clamp load and vibration resistance are paramount. The zinc plating offers a cost-effective barrier against oxidation, making these Phillips drive screws ideal for both indoor and moderate outdoor applications requiring long-term reliability.
Specification Summary & Compliance
This screw features a 4-40 UNC coarse thread with Class 2A tolerance for precise fit, fully threaded along a 5/16" length. It meets ASME B18.13 manufacturing specifications and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring adherence to international quality and environmental standards for safe industrial use.
