S-90403A121 4-40 x 1" 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 corrosion resistance through zinc-plated steel construction, extending service life in demanding industrial environments
- Reliable vibration resistance with integrated internal-tooth lock washer that maintains secure fastening under dynamic loads
- High tensile strength performance rated at 60,000 psi for critical applications requiring dependable load-bearing capability
- Optimized drive engagement with Phillips No. 1 drive style providing efficient installation and reduced cam-out risk
- Precision thread compatibility with Class 2A UNC coarse threads ensuring consistent mating with standard components
- Enhanced durability from Rockwell B69 hardness rating that resists wear and deformation during repeated use
- Full-threaded design offering maximum grip length and uniform stress distribution along the entire fastener
Professional Applications & Engineering Value
These zinc-plated steel rounded head screws with internal-tooth lock washers provide engineered solutions for vibration-prone assemblies across industrial machinery, electronic enclosures, and automotive components. The 4-40 UNC coarse thread configuration delivers rapid installation while maintaining Class 2A thread fit precision, eliminating cross-threading issues in production environments. The integrated lock washer system addresses common loosening problems in dynamic applications, while the zinc plating offers essential corrosion protection for extended service intervals. The pan head profile with Phillips No. 1 drive combines low-profile clearance requirements with reliable torque transmission, making these fasteners ideal for space-constrained assemblies requiring repeated maintenance access.
Specification Summary & Compliance
Manufactured to exacting ASME B18.13 specifications with Class 2A thread fit tolerance for consistent mating performance. These fully threaded screws feature UNC coarse threads with right-hand direction and comply with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. The mechanical properties include 60,000 psi tensile strength and Rockwell B69 hardness rating, ensuring reliable performance in industrial fastening applications.
