S-91259A911 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws
Shoulder 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 tensile strength of 140,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
- Superior corrosion resistance from the black oxide finish prolongs service life in harsh industrial environments.
- Precise Class 3A thread fit with UNC coarse threads provides secure, vibration-resistant connections for demanding assemblies.
- Knurled socket head with hex drive allows for easy installation and removal, even in tight spaces.
- Accurate shoulder dimensions with tight tolerances ensure proper alignment and smooth rotation in pivot and bearing applications.
- High hardness rating (Rockwell C32) maintains thread integrity and wear resistance over repeated use.
- Compliance with industry standards including ASME B18.3 guarantees consistent quality and interchangeability.
Professional Applications & Engineering Value
This alloy steel shoulder screw is engineered to address critical alignment and durability challenges in precision machinery. The 1/4"-20 UNC coarse thread and Class 3A fit deliver secure fastening with minimal loosening under vibration, ideal for automotive, aerospace, and heavy equipment assemblies. The black oxide finish enhances corrosion resistance, extending component life in humid or chemically aggressive settings. With a 7/16" shoulder length and controlled diameter tolerances, it provides exact positioning for rotating parts like gears, pulleys, and linkages, reducing wear and maintenance downtime. Its socket head design with knurling ensures easy tool engagement, streamlining installation in confined spaces while meeting rigorous ASME B18.3 specifications for reliability.
Specification Summary & Compliance
This shoulder screw adheres to Class 3A thread tolerances for precise fit, with UNC coarse threads (1/4"-20) and a shoulder diameter tolerance of -0.004" to -0.002". Manufacturing complies with ASME B18.3 and material standards per ASTM A574, ensuring dimensional consistency. It is fully RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, supporting environmental and safety regulations for industrial use.
