S-91205A561 1/4"-28 x 5/8" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws

Key Features & Benefits at a Glance

• Secure vibration-resistant fastening with nylon patch thread locker that maintains integrity in temperature ranges from -70°F to 250°F
• Exceptional tensile strength of 170,000 psi for reliable performance in high-stress industrial applications
• Precise Class 3A thread fit ensuring superior engagement and reduced risk of cross-threading during assembly
• Durable black-oxide finish on alloy steel providing enhanced corrosion resistance and extended service life
• Standard hex drive compatibility allowing for easy installation with common tools in confined spaces
• Full thread coverage along the 5/8" length for maximum grip and load distribution
• Rockwell C37 hardness delivering excellent wear resistance and durability under repeated use

Professional Applications & Engineering Value

These socket head cap screws with nylon patch locking technology solve critical vibration-induced loosening problems in machinery, automotive, and aerospace assemblies. The black-oxide alloy steel construction combined with UNF fine threads provides superior fatigue resistance where precise torque retention is essential. Engineered to withstand extreme temperature fluctuations while maintaining clamping force, these Class 3A thread fit fasteners prevent costly downtime in automated production systems and precision equipment. The hex drive socket head design enables high-torque installation in space-constrained applications where reliability cannot be compromised.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with Class 3A thread tolerance for precision fit. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Meets ASTM A574 material standards with consistent UNF fine thread geometry and right-hand thread direction for industry-standard compatibility.