S-90298A585 1/4"-20 ASME B18.3 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
- Superior corrosion resistance with 18-8 stainless steel construction and passivated finish for extended service life in harsh environments
- Precise component alignment through Class 3A thread fit and controlled shoulder diameter tolerance (±0.001") ensuring reliable assembly
- High-strength performance with 70,000 psi tensile strength and Rockwell B55 hardness for demanding industrial applications
- Secure tool engagement via hex socket drive and knurled head texture preventing slippage during installation
- Optimized shoulder design featuring 1 1/4" shoulder length with tight tolerance control for accurate component positioning
- Industry-standard compatibility with UNC coarse threading (1/4"-20) ensuring interchangeability across equipment
- Regulatory compliance meeting ASME B18.3 specifications and environmental standards (RoHS 3, REACH) for global applications
Professional Applications & Engineering Value
Engineered for precision mechanical assemblies, these 18-8 stainless steel shoulder screws provide critical alignment functions in rotating machinery, automation systems, and precision instruments. The passivated finish enhances corrosion resistance in industrial environments while maintaining dimensional stability. The 1/4"-20 UNC coarse thread with Class 3A fit ensures vibration-resistant fastening, while the precisely machined shoulder (5/16" diameter) acts as a reliable datum surface for components like gears, pulleys, and bearings. The combination of 70,000 psi tensile strength and hex socket drive with knurled head delivers both structural integrity and installation reliability, making these fasteners ideal for applications requiring repeated disassembly and maintenance.
Specification Summary & Compliance
This precision shoulder screw features Class 3A thread fit per ASME B18.3 standards with UNC 1/4"-20 coarse threading. Critical dimensions include shoulder diameter (5/16" with ±0.001" tolerance) and shoulder length (1 1/4" with ±0.005" tolerance). Manufacturing complies with ASME B18.3 specifications and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for restricted substances.
