Industry News

Spring washers, flat washers or lock nuts? Choosing the right locking solution

2026-08-29

Compiled by JIALI Industrial (164.hk) — a Hong Kong fastener supplier specialising in screws, bolts, nuts and selection know-how.

Locking principle and applications

A spring washer relies on the elasticity of its split opening to maintain continuous tension and take up play, which suits light-load, low-vibration joints. A flat washer mainly spreads clamping load and protects the workpiece surface — it does not provide locking by itself. Lock nuts (nylon insert, flange face) lock through friction or controlled deformation and offer the best vibration resistance. Use a spring washer for light, low-vibration connections; for critical or highly vibrating joints, prefer lock nuts.

Common sizes and selection comparison

Spring washers are commonly made of zinc-plated 65Mn spring steel, covering M3–M30. Flat washers follow GB/T 97.1 (grade A) and DIN 125 in large and small outer-diameter series. Nylon insert lock nuts are typically DIN 985, while flange lock nuts correspond to GB/T 6177 (DIN 6923). For vibrating equipment such as motors, pumps and conveyors, choose nylon insert or flange nuts; for static load-bearing joints, a flat washer with a standard nut is sufficient.

Combinations and common mistakes

A common mistake is treating the flat washer as a locking device — it handles load spreading and surface protection, while locking should come from a spring washer or lock nut, and the two can be combined when needed. Under high preload, spring washers are less effective; lock nuts or thread-locking adhesive (anaerobic) are more reliable. Need a locking solution? Contact JIALI Industrial (164.hk) with your vibration conditions and size requirements for fast advice.

Spring washers, flat washers or lock nuts? Choosing the right locking solution

Locking principle and applications

Common sizes and selection comparison

Combinations and common mistakes

Related Reading