S-91211A188 1/2"-13 x 2 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Thread-Locking Hex Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant secure locking with permanent nylon patch thread locker that maintains integrity across a wide temperature range from -55° to 250°F
• Exceptional strength for demanding applications with Grade 8 classification providing 150,000 psi tensile strength and Rockwell C33 hardness
• Superior corrosion protection through zinc yellow-chromate plating on steel construction for extended service life
• Reliable installation and removal with external hex drive design and standard 3/4" head width for optimal torque application
• Precision thread engagement with Class 2A thread fit and UNC coarse thread profile ensuring consistent performance
• Versatile partial threading design allowing for both secure fastening and adjustable positioning in assembly applications
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed quality and interoperability

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications where vibration resistance and thermal stability are critical, these Grade 8 hex head screws with nylon patch thread locker provide permanent fastening solutions that withstand extreme operating conditions. The zinc yellow-chromate plated steel construction offers superior corrosion protection in harsh environments, while the UNC coarse thread design ensures quick assembly and reliable performance in structural applications, machinery, and equipment manufacturing. The combination of 150,000 psi tensile strength and Rockwell C33 hardness makes these partially threaded screws ideal for high-stress applications where joint integrity cannot be compromised, effectively solving common industrial challenges of fastener loosening under dynamic loads and thermal cycling.

Specification Summary & Compliance

These 1/2"-13 x 2 1/2" hex head screws feature Class 2A thread fit tolerance for precise engagement and are manufactured to comply with ASME B18.2.1 and SAE J429 standards. The fasteners maintain dimensional accuracy with UNC coarse thread profile, 1/2"-13 thread size, and minimum thread length of 1-1/4". The construction meets industry specifications for Grade 8 strength classification with verified mechanical properties including 150,000 psi tensile strength and Rockwell C33 hardness rating.