S-91273A779 M4 Shoulder Screws

Key Features & Benefits at a Glance

• Corrosion-resistant 18-8 stainless steel construction ensures long-term reliability in harsh industrial environments, reducing maintenance and replacement costs.
• Black oxide finish enhances surface durability and provides a sleek, low-reflective appearance suitable for precision assemblies.
• Knurled socket head with 2 mm hex drive offers superior grip and torque transmission, minimizing tool slippage during installation.
• Class 5g6g thread fit and M4 x 0.7mm coarse pitch guarantee consistent, vibration-resistant fastening in high-stress applications.
• 70,000 psi tensile strength and Rockwell B55 hardness deliver exceptional mechanical performance, supporting heavy loads without failure.
• Precision shoulder diameter (4 mm) with tight tolerance control enables accurate alignment and smooth rotation in machinery and pivoting joints.
• Full compliance with RoHS 3 and REACH regulations ensures environmental safety and global supply chain compatibility.

Professional Applications & Engineering Value

This M4 shoulder screw is engineered to address critical alignment and wear challenges in industrial assemblies. The 18-8 stainless steel base material provides inherent corrosion resistance, ideal for humid or chemically exposed settings, while the black oxide finish adds an extra layer of protection against abrasion. The precision shoulder (4 mm diameter) acts as a reliable pivot or spacer, reducing friction in moving parts like conveyor systems, robotic arms, and precision machinery. With a coarse thread pitch (0.7 mm) and Class 5g6g thread fit, it ensures quick installation and stable retention under dynamic loads, minimizing loosening from vibrations. The knurled socket head enhances tool engagement, speeding up assembly in tight spaces without compromising torque accuracy.

Specification Summary & Compliance

This shoulder screw adheres to metric system standards with an M4 thread size, 0.7 mm coarse pitch, and Class 5g6g thread fit for consistent dimensional accuracy. The shoulder diameter tolerance is controlled between -0.04 to -0.01 mm, and shoulder length tolerance from 0 to 0.25 mm, ensuring precise fit in industrial applications. Manufactured from 18-8 stainless steel with a black oxide finish, it meets Rockwell B55 hardness and delivers 70,000 psi tensile strength with a minimum shear strength of 35,000 psi. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting safe and sustainable usage.