S-91205A584 5/16"-18 x 1 3/4" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with nylon patch that maintains integrity across a wide temperature range from -70° to 250°F
• Exceptional tensile strength of 170,000 psi ensures reliable performance under heavy loads and high-stress applications
• Precision Class 3A thread fit provides superior engagement and consistent clamping force in demanding assemblies
• Corrosion-resistant black-oxide finish on alloy steel extends service life in harsh industrial environments
• Standard hex socket drive with 1/4" drive size enables secure tool engagement and high torque application
• Partially threaded design offers optimal grip length while reducing weight and material usage
• Industry-standard compliance with ASME B18.3 ensures dimensional accuracy and interchangeability

Professional Applications & Engineering Value

Engineered for critical industrial applications where vibration resistance and structural integrity are paramount, these black-oxide alloy steel socket head cap screws deliver exceptional performance in machinery, automotive, and heavy equipment assemblies. The nylon patch locking feature effectively prevents loosening under dynamic loads, eliminating the need for secondary locking devices. With UNC coarse threads and Class 3A thread fit, these fasteners provide rapid installation and reliable engagement in both through-holes and tapped applications. The combination of Rockwell C37 hardness and 170,000 psi tensile strength ensures these screws withstand extreme mechanical stresses while the black-oxide surface treatment offers enhanced corrosion protection for extended service life in demanding environments.

Specification Summary & Compliance

This 5/16"-18 UNC socket head cap screw features precise Class 3A thread fit with coarse thread spacing and partial threading up to 1-1/8" minimum thread length. Manufactured to ASME B18.3 specifications using ASTM A574 alloy steel, the fastener meets rigorous dimensional standards. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global markets. The combination of material specifications, thread standards, and surface treatment provides reliable performance for professional industrial applications requiring high-strength fastening solutions.