S-91257A426 1/4"-28 x 7" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws
High-Strength Grade 8 Steel Hex Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Maximum load-bearing capacity with 150,000 psi tensile strength, ideal for high-stress industrial applications
- Superior corrosion resistance through zinc yellow-chromate plating, extending service life in harsh environments
- Precise thread engagement with Class 2A UNF fine threads ensuring reliable, vibration-resistant connections
- Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated stress
- Optimized partial threading providing superior clamping force distribution across the 7" length
- Industry-standard compliance with ASME B18.2.1/SAE J429 specifications for guaranteed interchangeability
- Easy installation and removal with external hex drive design accommodating standard wrench tools
Professional Applications & Engineering Value
These Grade 8 hex head screws deliver exceptional engineering value in demanding applications where high tensile strength and corrosion resistance are critical. The 1/4"-28 UNF fine threading provides superior resistance to vibrational loosening in machinery, automotive, and construction equipment. The zinc yellow-chromate plating creates a protective barrier against environmental factors, while the partially threaded design ensures optimal stress distribution across the 7" length. These heavy-duty fasteners solve common industrial challenges of joint failure and material degradation, making them ideal for structural assemblies, equipment frames, and high-vibration environments requiring Class 2A thread fit precision and long-term reliability.
Specification Summary & Compliance
Manufactured to exact inch system dimensions with Class 2A thread fit tolerance for precision assembly. Complies with ASME B18.2.1 and SAE J429 specifications, ensuring dimensional consistency and mechanical properties. Features UNF fine thread spacing (28 TPI) with right-hand thread direction and minimum 1" thread length. The zinc yellow-chromate plating meets industry standards for corrosion protection, while the Grade 8 classification guarantees consistent 150,000 psi tensile strength and Rockwell C33 hardness across all production batches.
