S-91280A551 M8 x 55 mm ISO 4017, DIN 933, SAE J1199, ISO 898 Medium-Strength Metric Class 8.8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating that protects against rust and extends service life in harsh environments
• High tensile strength of 110,000 PSI ensures reliable performance under heavy loads and prevents fastener failure
• Class 8.8 strength grade provides excellent durability and load-bearing capacity for demanding industrial applications
• Fully threaded design offers maximum grip and uniform clamping force along the entire length
• Coarse thread pitch (1.25mm) enables faster installation and reduced cross-threading risks
• External hex drive head allows for easy installation with standard tools and high torque application
• Multiple international standard compliance including ISO 4017 and DIN 933 ensures interchangeability and quality consistency

Professional Applications & Engineering Value

These M8 hex head screws are engineered to solve critical fastening challenges in industrial settings where vibration resistance and structural integrity are paramount. The Class 8.8 steel construction combined with Rockwell C21 hardness provides exceptional resistance to shear forces and mechanical stress, making them ideal for heavy machinery, structural steel connections, and automotive assemblies. The zinc plating finish offers reliable corrosion protection in environments exposed to moisture and chemicals, significantly extending maintenance intervals. With their fully threaded metric design and coarse thread pitch, these fasteners deliver superior clamping force distribution and faster installation times compared to fine-thread alternatives, reducing labor costs while ensuring long-term reliability in critical applications.

Specification Summary & Compliance

This M8 x 1.25 x 55mm hex head screw features precision Class 6h thread fit tolerance ensuring consistent engagement and optimal performance. Manufactured in compliance with ISO 4017, DIN 933, and SAE J1199 specifications for dimensional accuracy and mechanical properties. The product meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming the absence of restricted hazardous substances. The ISO 898 standard compliance guarantees consistent mechanical properties including the specified tensile strength and hardness values across production batches.