DIN 9021 Large Plain Washer

Standard: DIN 9021
Material: Stainless Steel
Thread Size: 1/4 – 1-1/2
Surface Treatment: Plain, Zinc Plated
Min Order: 5000pcs
Sample: Free sample (after quote)
Delivery time: 30 – 45 Days

Product Overview

Product Application

DIN 9021 is a metric standard for large-diameter flat washers; its corresponding international equivalent is ISO 7093. It is specifically designed to specify large-outer-diameter flat washers (commonly known as large-edge washers or oversized washers / fender washers). The key characteristic of this type of washer is that its outer diameter (d₂) is approximately three times the inner diameter (d₁, i.e., the nominal diameter of the applicable thread) (~3d).

Compared to standard washers, it provides a larger bearing surface, which helps distribute loads, protect assembly surfaces, and improve fastening stability. It is commonly used to join fragile or soft materials (such as wood, plastic, and thin metal sheets), or to cover oversized or irregularly shaped screw holes.

DIN 9021 has been replaced by DIN EN ISO 7093 series, which maintains similar dimensional requirements while updating international standard alignment.

For global procurement, ISO 7093 is generally preferred, while DIN 9021 remains widely recognized in existing machinery and engineering drawings.

Draw

Specification

Features

1. Large Bearing Surface

DIN 9021 washers feature an enlarged outside diameter, typically around 3× the nominal thread diameter, providing better load distribution compared with standard flat washers.

This design helps reduce surface pressure and prevents damage to softer materials such as aluminum, wood, plastic, and thin metal sheets.

2. Enhanced Assembly Stability

The larger contact area improves connection stability by spreading clamping forces over a wider surface.

Suitable for applications requiring:

Higher load distribution
Reduced surface deformation
Improved fastening reliability

3. Versatile Industrial Applications

DIN 9021 washers are commonly used with:

Hex bolts
Structural screws
Machine screws
Solar mounting fasteners
Equipment assemblies

Typical industries include:

Construction
Automotive
Mechanical engineering
Renewable energy
Industrial equipment

DIN 9021 vs DIN 125 Flat Washer

DIN 9021

Large outside diameter
Higher load distribution capability
Designed for applications requiring wider support area

DIN 125

Standard flat washer
Smaller outside diameter
General fastening applications

Key Difference:
DIN 9021 provides a larger bearing surface, while DIN 125 is used for standard bolt and nut assemblies.

Product Advantages

Large Load Distribution
Reduces stress concentration and protects fastening surfaces.
Improved Surface Protection
Prevents bolt heads or nuts from damaging assembly materials.
Wide Material Availability

Available in stainless steel, carbon steel, and customized materials for different environments.

Common Questions

What is DIN 9021 washer used for?

DIN 9021 washers are used to distribute bolt loads over a larger surface area, reducing pressure and protecting connected materials.

What is the difference between DIN 9021 and DIN 125?

DIN 9021 has a larger outside diameter than DIN 125, providing better load distribution for applications requiring wider support.

Can DIN 9021 washers be used with oversized holes?

Absolutely.

One of the main reasons engineers specify DIN 9021 is to bridge oversized or elongated holes while maintaining proper clamping force and preventing fastener pull-through.