S-91283A310 1 1/4"-12 x 4" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws
Medium-Strength Grade 5 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
- Exceptional load-bearing capacity with 100,000 psi tensile strength, ideal for heavy-duty structural connections.
- Superior wear resistance due to Rockwell C19 hardness, ensuring long-term reliability in demanding environments.
- Precise, vibration-resistant fit from Class 2A thread tolerance, minimizing loosening under dynamic loads.
- Optimized for high-torque applications with a large 1 7/8" external hex head, allowing for secure tool engagement.
- Enhanced fatigue resistance from the fine 12 UNF thread spacing, distributing stress more evenly.
- Reduced installation time and weight with a partially threaded 4" shank, focusing strength where needed.
- Guaranteed material and manufacturing consistency through compliance with ASME B18.2.1 and Grade 5 standards.
Professional Applications & Engineering Value
This Grade 5 Steel Hex Head Screw is engineered to address critical challenges in industrial assembly, such as joint integrity under high vibration and tensile stress. The 1 1/4"-12 UNF fine thread provides superior clamping force and resistance to loosening compared to coarse threads, making it ideal for machinery, heavy equipment frames, and structural steel connections. The partially threaded design ensures that the unthreaded shank bears shear loads effectively, while the threaded portion secures the nut. Manufactured from high-strength steel and heat-treated to Rockwell C19 hardness, it withstands repetitive dynamic loads and harsh environmental conditions, reducing maintenance frequency and downtime in industrial applications.
Specification Summary & Compliance
This screw adheres to Class 2A thread fit for consistent assembly and meets ASME B18.2.1 dimensional and mechanical requirements. It is fully RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, ensuring the absence of hazardous substances. The Grade 5 classification confirms a minimum tensile strength of 100,000 psi, with a right-hand UNF thread and fine spacing for precise fastening in critical engineering applications.
