Lock Washers

Lock Washers — Spring Washers, Tooth Lock Washers & Nordlock

Lock washers resist bolt and nut loosening under vibration and dynamic loading — providing mechanical resistance to rotation that maintains joint preload over service life. AIMS Industrial sells a number of lock washers including spring (split) lock washers, internal and external tooth lock washers, and Nordlock wedge-locking washers in zinc-plated and stainless steel for the full range of vibration-resistant fastening applications.

Lock Washers We Stock

• Spring (Split) Lock Washers: Split spring lock washers (DIN 127) are the most widely used lock washer — a split ring with opposing ends at different heights. When the bolt is fully tightened, the ring flattens and the sharp cut ends bite into the bolt and mating surface, resisting rotation. Available M4 to M24 in zinc-plated and stainless steel.
• Internal Tooth Lock Washers: Internal tooth (star) lock washers have serrated teeth on the inner diameter that engage both the bolt shank and mating surface under tightening — providing positive resistance to rotation. Preferred in electrical applications for maintaining conductor contact and anti-rotation function simultaneously.
• External Tooth Lock Washers: External tooth (star) lock washers have serrated teeth on the outer diameter — providing higher locking force than internal tooth washers for the same washer size. Used in high-vibration automotive and machinery applications.
• Nord-Lock Wedge-Locking Washers: Nord-Lock washers use a wedge-locking mechanism — two washers with matching cam-face serrations on the inner faces and radial serrations on the outer faces. The cam angle exceeds the bolt thread lead angle, preventing rotation even under severe vibration. A proven solution for safety-critical and high-vibration joints where spring washers are insufficient.

Lock Washer Selection Guide

• Spring Washers — Limitations: Spring lock washers are adequate for moderate vibration environments. Research (Junker test) shows that spring lock washers can fail to prevent loosening under severe lateral vibration (transverse loading). For high-vibration or safety-critical joints, Nord-Lock or all-metal prevailing torque nuts provide superior performance.
• Tooth Washers for Electrical Contact: Internal tooth lock washers are standard in electrical cabinet and switchboard assembly — the teeth break through surface oxide and plating to ensure low-resistance electrical contact between the fastener and grounding surface, combining electrical and mechanical functions.
• Nord-Lock for Critical Applications: Nord-Lock washers are the engineered solution for joints where loosening is not acceptable — railway, structural steel, industrial machinery, and transportation equipment. The Nordlock self-locking mechanism is verifiable and predictable, unlike spring washers that depend on surface friction.

Australian Business, Local Supply: As a proudly Australian business since 1988, we stock locally and work with trusted local Australian manufacturers and distributors to ensure fast, reliable supply.

Expert Support: Need help buying the right product for your application? Contact our team for application-specific advice or request a quote.

See our full fasteners range including spring washers, flat washers, and hex lock nuts.