Flat Washers are selected when an assembly calls for load distribution and anti-loosening under a bolt or nut. This application guide to the ISO 7089 / ISO 7093 type covers concrete end-uses, the specification checklist, correct installation, and where an alternative fastener performs better. Stocked across roughly M1.6 to M64, they cover general to heavy-duty work.
Typical Applications for Flat Washers
The most common settings where these are specified:
- Vibration applications: spring and serrated types that maintain tension under cyclic load.
- Timber & soft materials: large-OD types that prevent pull-through.
- General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
- 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.
How to Specify Flat Washers for Your Application
- Size: Match the nominal size to the mating thread or hole. This product spans M1.6–M64; 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 ISO 7089 / ISO 7093. 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 Flat 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 Flat 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.
