S-91273A561 1/4"-20 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments and reducing replacement frequency.
• Enhanced durability and wear resistance from the black oxide finish, providing added protection against abrasion and minimal galling.
• High tensile strength of 70,000 psi ensures reliable performance under heavy loads, minimizing the risk of fastener failure.
• Precise alignment and smooth rotation due to the standard shoulder fit and Class 2A thread tolerance, reducing assembly errors.
• Secure, non-slip installation with the knurled socket head and hex drive, allowing for high torque application without stripping.
• Broad compatibility with UNC coarse threads, facilitating quick assembly and disassembly in various machinery and fixtures.
• Compliance with RoHS 3 and REACH regulations ensures environmental safety and suitability for global industrial supply chains.

Professional Applications & Engineering Value

This 1/4"-20 UNC shoulder screw is engineered to address critical alignment and pivot point requirements in precision assemblies. The 18-8 stainless steel material offers excellent resistance to rust and oxidation, making it suitable for applications in moist or chemically aggressive settings, such as packaging machinery, automotive jigs, and electronic enclosures. The black oxide finish not only enhances corrosion protection but also reduces friction during operation, extending the component's service life. With a 3/8" shoulder length and precise diameter tolerances, it provides a stable bearing surface that prevents lateral movement and ensures accurate positioning of moving parts. This design is ideal for use in stripper bolts, rotating shafts, and guiding systems where reliability and repeatability are paramount, reducing downtime and maintenance costs in industrial screw applications.

Specification Summary & Compliance

This shoulder screw adheres to UNC coarse thread standards with a Class 2A thread fit for consistent engagement and ease of assembly. Key dimensions include a shoulder diameter of 1/4" with a tolerance of -0.004" to -0.002" and a shoulder length of 1/4" with a tolerance of -0.005" to 0.005", ensuring high precision. Manufactured from 18-8 stainless steel with a hardness of Rockwell B55, it meets mechanical properties such as 70,000 psi tensile strength and 35,000 psi minimum shear strength. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting safe and sustainable industrial use.