S-90403A551 1/4"-20 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 vibration resistance with integrated internal-tooth lock washer that maintains clamping force in high-stress applications
- Enhanced corrosion protection through zinc-plated steel construction for extended service life in demanding environments
- High tensile strength rating of 60,000 psi ensures reliable performance in heavy-duty fastening applications
- Optimized drive engagement with Phillips No. 3 drive for efficient installation and reduced cam-out risk
- Secure thread locking capability through Class 2A UNC coarse threads that provide excellent holding power
- Consistent performance with Rockwell B69 hardness rating ensuring dimensional stability under load
- Complete thread coverage along the 1" length for maximum grip and load distribution
Professional Applications & Engineering Value
These zinc-plated steel pan head screws with internal-tooth lock washers are engineered to solve critical industrial fastening challenges where vibration-induced loosening compromises assembly integrity. The combination of UNC coarse threading and Class 2A thread fit ensures rapid installation while maintaining precise tolerances for repetitive assembly operations. The rounded pan head profile with Phillips drive provides a low-profile fastening solution that resists snagging while accommodating standard driving tools. Ideal for machinery assembly, electrical enclosures, and automotive components, these fully threaded screws deliver reliable performance in applications requiring both vibration resistance and corrosion protection. The integrated locking mechanism eliminates the need for separate washers, streamlining inventory and reducing installation time in production environments.
Specification Summary & Compliance
Manufactured to exacting standards with Class 2A thread fit and UNC 1/4"-20 coarse threading for consistent performance. Complies with ASME B18.13 specifications for dimensional accuracy and mechanical properties. Meets environmental regulations including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) standards for hazardous substance restrictions. Features include 1" fully threaded length, 0.492" head diameter, and internal-tooth lock washer with 0.478" OD for secure fastening applications.
