S-90342A127 1/4"-20 x 1/2" Alloy Steel Socket Head Screws with Split Lock Washer

Key Features & Benefits at a Glance

• Superior vibration resistance thanks to the integrated split lock washer that prevents loosening under dynamic loads
• Exceptional tensile strength of 180,000 psi ensures reliable performance in high-stress industrial applications
• Enhanced durability and corrosion resistance provided by the black-oxide finish on both the alloy steel screw and washer
• Precise, secure fastening achieved with Class 3A UNC coarse threads for superior fit and reduced cross-threading risk
• High torque capability enabled by the 3/16" hex socket drive, allowing for easy installation in confined spaces
• Consistent material hardness at Rockwell C39 guarantees long-term wear resistance and structural integrity
• Full thread engagement along the 1/2" length provides maximum grip strength and load distribution

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to solve critical fastening challenges in demanding environments. The combination of 180,000 psi tensile strength and Rockwell C39 hardness ensures reliable performance in heavy machinery, automotive assemblies, and industrial equipment where vibration-induced loosening is a common failure point. The integrated split lock washer maintains clamp force under dynamic loads, while the Class 3A UNC coarse threads provide quick assembly and superior resistance to stripping. The black-oxide surface treatment offers enhanced corrosion protection for extended service life in harsh operating conditions, making these socket head cap screws ideal for applications requiring both high strength and vibration resistance.

Specification Summary & Compliance

This fastener features precision 1/4"-20 UNC Class 3A threads with coarse spacing and right-hand direction, manufactured to exacting dimensional standards. The fully threaded 1/2" length provides complete engagement capability, while the standard socket head profile with 3/16" hex drive ensures compatibility with common installation tools. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, meeting the latest industry standards for hazardous substance restrictions.