We stock a comprehensive range of washers and retaining rings, from standard flat washers (Form A to DIN 125, Form B, C and D) through to spring washers, shakeproof washers, Nord-Lock, Schnorr disc springs and shim washers. All types are available in steel and stainless steel, with specialist materials available to order. Our range also includes circlips, E-clips, and starlock washers.
What is the difference between Form A, Form B, Form C, and Form D washers?
The forms refer to the outside diameter relative to the bore. Form A (DIN 125) is the standard flat washer. Form B has a slightly larger OD. Form C is a wider repair washer used to spread load over a larger area, and Form D is wider still. Form C and D are often used where the bolt passes through an oversized or slotted hole.
When should I use a Nord-Lock washer instead of a spring washer?
Nord-Lock wedge-locking washers are significantly more effective than single-coil spring washers at preventing bolt loosening from vibration. They work by creating a wedge effect between two interlocking faces. Spring washers provide some tension but are now considered inadequate for vibration-critical joints in many engineering standards.
What washer should I use with stainless steel bolts?
Use a stainless steel Form A washer in the matching grade — A2 washer with A2 bolt, A4 with A4. Mixing stainless bolts with zinc-plated washers can cause galvanic corrosion. For locking applications in stainless, Nord-Lock and Schnorr washers are both available in A4 stainless.
