Flat Washer

A flat washer is a thin disc with a central hole. It spreads the load of a bolt or nut over a wider area and protects the surface being fastened.

A flat washer spreads a bolt or nut load over a wider area of the clamped part. It sits under a nut or a bolt head and matches the thread and class of the fastener it serves. A washer can be used with a bolt, screw or stud in general engineering and construction joints.

Zinc plating gives a bright finish and mild corrosion resistance for indoor use. Hot dip galvanising gives a thicker coating for outdoor or damp conditions. Black oxide gives a dark finish with light oil protection.

This kind of washer is often made in steel, stainless steel, brass, or plastic. Steel grades are common for general use. Stainless steel grades resist rust.

This is a general guide to checking this kind of part. It says nothing about any supplier's parts.

Ask for a certificate of conformance if you need traceability. Check the hole diameter, outer diameter, and thickness against your requirement. Inspect for burrs, cracks, or coating defects on receipt.