Spring washer Koelner DIN127 M4 A2, stainless steel, pack of 24

Spring washer Koelner DIN127 M4 A2 is a stainless steel locking washer designed for use with M4 bolts and screws. Manufactured to DIN127 geometry, this A2 stainless variant provides corrosion resistance suitable for general indoor and mild outdoor environments. Supplied as a pack of 24, the washers are intended to increase joint security and resist loosening due to vibration in a variety of assemblies and equipment.

Advantages

The DIN127 form delivers a consistent split and spring action that creates axial tension on fasteners, improving clamp load retention. Made from A2 stainless steel, these washers combine mechanical resilience with resistance to oxidation, making them suitable for applications where moderate corrosion resistance is required. The standard M4 size ensures compatibility with common metric fasteners and simplifies inventory management by using a widely recognized dimension.

Suitable for

• Mechanical assemblies and machinery where vibration resistance is required
• Furniture fastenings and fittings that use M4 bolts or screws
• Electrical enclosures and equipment with moderate exposure to humidity
• General repair, maintenance and DIY fastening tasks

Key specifications

• Washer standard: DIN127 geometry (external and internal dimensions per DIN127 for split spring washers)
• Size: M4 (compatible with M4 bolts and screws)
• Material: A2 stainless steel (austenitic stainless offering corrosion resistance for general use)
• Finish: natural stainless steel surface
• Quantity: pack of 24 pieces

How to use

Place the spring washer between the nut (or the screw head) and the joined parts with the split and beveled side oriented as specified by the installation practice for DIN127 washers. Tighten the fastener to the recommended torque for M4 connections so the washer exerts its spring action to maintain axial force and reduce the risk of self-loosening under vibration. Ensure mating surfaces are clean and that the washer seats flat against the contact surface for optimal performance.

Usage recommendations

For assemblies exposed to aggressive chemicals, saltwater, or prolonged outdoor conditions, consider specifying a higher-corrosion-grade stainless material. Verify torque values for the specific bolt grade used and inspect fastened joints periodically in high-vibration environments to confirm continued effectiveness.