S-91257A577 1/4"-28 x 4 1/2" 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 and Grade 8 classification, ideal for high-stress industrial environments
- Superior Corrosion Resistance from zinc yellow-chromate plating, extending service life in harsh conditions
- Precision Thread Engagement with Class 2A UNF fine threads ensuring reliable, vibration-resistant connections
- Optimized Torque Transmission through external hex drive design and 7/16" head width for secure installation
- Enhanced Durability with Rockwell C33 hardness maintaining structural integrity under repeated loads
- Versatile Partial Threading allowing both clamping and alignment functions in heavy-duty assemblies
- Industry Standard Compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed interoperability
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, these Grade 8 hex head screws solve critical fastening challenges in construction, machinery, and structural assemblies. The UNF fine threading (1/4"-28) provides superior resistance to vibrational loosening compared to coarse threads, while the partial threading design enables precise clamping force distribution. The zinc yellow-chromate plating creates a protective barrier against corrosion in outdoor or chemically aggressive environments. With 4 1/2" length and external hex drive, these screws deliver optimal performance in high-torque applications where reliability and ASME B18.2.1 compliance are paramount for safety and longevity.
Specification Summary & Compliance
This 1/4"-28 UNF hex head screw features Class 2A thread fit tolerances for precise engagement, partial threading with minimum 3/4" thread length, and complies with ASME B18.2.1 and SAE J429 manufacturing standards. The Grade 8 classification ensures consistent mechanical properties including 150,000 psi tensile strength and Rockwell C33 hardness. The zinc yellow-chromate finish provides corrosion protection while meeting industrial requirements for heavy-duty fastening applications.
