S-90403A839 1/4"-28 x 1/2" 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 with zinc-plated steel construction for extended service life in harsh industrial environments
- Reliable vibration resistance through integrated internal-tooth lock washers that maintain secure fastening under dynamic loads
- Enhanced driving efficiency with Phillips No. 3 drive design for quick installation and reduced assembly time
- Precise thread engagement with Class 2A UNF fine threads ensuring consistent, secure connections in critical applications
- High load-bearing capacity supported by 60,000 psi tensile strength and Rockwell B69 hardness for demanding mechanical applications
- Comprehensive compliance with ASME B18.13 standards and environmental regulations including RoHS 3 and REACH
- Optimal head design featuring rounded pan profile for reduced surface protrusion and improved aesthetic integration
Professional Applications & Engineering Value
These zinc-plated steel rounded head screws with integrated internal-tooth lock washers provide engineered solutions for vibration-prone industrial equipment and machinery. The combination of UNF fine threading and Class 2A thread fit ensures precise alignment and consistent clamping force in critical assemblies, while the Phillips drive system enables efficient installation in confined spaces. The zinc plating offers essential corrosion protection for manufacturing environments, automotive components, and electrical enclosures where moisture and chemical exposure are concerns. The fully threaded design maximizes engagement depth, making these industrial screws ideal for applications requiring uniform stress distribution across the entire fastener length.
Specification Summary & Compliance
Manufactured to precise dimensional standards with Class 2A thread fit and UNF 1/4"-28 fine thread specifications. Complies with ASME B18.13 manufacturing standards and meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance. Features include 1/2" length, 0.492" head diameter, and internal-tooth lock washer with 0.478" OD for secure fastening performance.
