S-90211A222 1/4"-20 x 3/4" SAE J429 Left-Hand Threaded High-Strength Steel Hex Head Screws
Left-Hand Threaded High-Strength 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 150,000 psi tensile strength for demanding industrial applications
- Superior corrosion protection through zinc yellow-chromate plating that extends service life in harsh environments
- Precise thread engagement with Class 3A fit and UNC coarse threading for reliable fastening in left-hand applications
- Maximum torque transmission via external hex drive design that prevents tool slippage during installation
- Premium material performance using Grade 8 steel with Rockwell C33 hardness for exceptional durability
- Full thread coverage along the 3/4" length for consistent clamping force distribution
- Industry compliance assurance meeting SAE J429 specifications for quality and reliability
Professional Applications & Engineering Value
Engineered for high-stress industrial environments, these Grade 8 hex head screws deliver critical performance where reverse-rotation applications demand exceptional strength. The left-hand UNC coarse threading provides secure fastening in machinery where standard right-hand threads would loosen under counter-clockwise motion. The zinc yellow-chromate plated steel construction offers superior corrosion resistance, making these fasteners ideal for automotive, manufacturing, and heavy equipment applications exposed to moisture and chemicals. With fully threaded design and external hex drive, installation becomes efficient while maintaining consistent clamping force across the entire engagement length, preventing joint failure in vibration-prone systems.
Specification Summary & Compliance
Manufactured to precise Class 3A thread fit tolerances with UNC coarse threading (1/4"-20) in left-hand direction. The 3/4" length features complete threading and complies with SAE J429 specifications for Grade 8 fasteners. The zinc yellow-chromate plating provides RoHS and REACH compliant corrosion protection while maintaining the mechanical properties required for industrial applications.
