S-90402A117 4-40 x 7/8" 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 corrosion resistance through zinc-plated steel construction, extending service life in demanding industrial environments
- Exceptional vibration resistance with integrated external-tooth lock washer that maintains secure fastening under dynamic loads
- High-strength performance with 60,000 psi tensile strength and Rockwell B69 hardness for reliable load-bearing capability
- Easy installation and removal with Phillips No. 1 drive that provides positive engagement and reduces tool slippage
- Precise thread engagement with Class 2A thread fit and UNC coarse threading for quick assembly and reduced cross-threading risk
- Maximum grip surface from the pan-style rounded head design that distributes clamping force evenly
- Full-thread engagement along the entire 7/8" length for consistent holding power throughout the fastened joint
Professional Applications & Engineering Value
These 4-40 UNC zinc-plated steel rounded head screws with external-tooth lock washers solve critical vibration-induced loosening problems in industrial equipment, machinery, and electronic enclosures. The combination of coarse threading and Class 2A thread fit ensures rapid assembly while maintaining precision alignment. The zinc-plated steel construction provides essential corrosion protection for environments exposed to moisture or chemicals, while the fully threaded design guarantees consistent clamping force across the entire fastened joint. The Phillips drive facilitates efficient installation in confined spaces, making these pan head screws ideal for assembly line applications where speed and reliability are paramount.
Specification Summary & Compliance
This fastener features precision 4-40 UNC coarse threads with Class 2A thread fit tolerances, ensuring consistent performance across industrial applications. Manufacturing complies with ASME B18.13 specifications for dimensional accuracy and quality. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental and safety standards for hazardous substances.
