Application guide for Fender Washers to DIN 9021. The core duty of the type is load distribution and anti-loosening under a bolt or nut. The typical industries, the how-to-specify checklist, assembly practice and the exclusion cases are set out below. Stocked across roughly M3 to M36, they cover general to heavy-duty work.
Typical Applications for Fender Washers
The most common settings where these are specified:
- Maintenance & repair (MRO): a stocked size for servicing existing plant where the original fastener spec must be matched.
- Fabrication & metalwork: bench and on-site assembly of steel frames, enclosures and weldments.
- Bolted structural joints: spreading load over soft or oversized holes and protecting the surface.
- Vibration applications: spring and serrated types that maintain tension under cyclic load.
- Timber & soft materials: large-OD types that prevent pull-through.
How to Specify Fender Washers for Your Application
- Size: Match the nominal size to the mating thread or hole. This product spans M3–M36; check the full table below for the exact dimensions of each size.
- Type & OD: Select flat for load spreading, spring/serrated for anti-loosening, or fender/large-OD for soft or oversized holes.
- Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- Standard: This product is supplied to DIN 9021. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.
Installation & Assembly Practice
- Place the washer under the rotating element (usually the nut) so tightening does not score the surface.
- Chamfered-hole side of a hardened washer faces the bolt head fillet.
- On serrated-flange hardware, do not add a plain washer — it defeats the serrations.
Common Selection Mistakes with Fender Washers
- Relying on a spring washer for locking on class 8.8+ joints — at high preload it flattens and adds nothing.
- Choosing an OD too small for soft material, so the head pulls through or embeds.
Where Fender Washers Are Not the Right Choice
A washer does not replace a locking feature on its own in severe vibration, and a spring washer adds little clamp on high-strength joints.