DIN 9021 Large Flat Washers
DIN 9021 covers wide flat washers with an outside diameter of roughly three times the bolt size — the familiar penny or mudguard washer. We supply penny washers in stainless steel A2 and A4 across a wide range of metric sizes.
Also known as: penny washers, mudguard washers, repair washers, fender washers, penny washer, mudguard washer.
DIN 9021 dimensions
| Bolt Size | Inside Diameter | Outside Diameter | Thickness |
|---|---|---|---|
| M2.5 | 2.7mm | 8mm | 0.8mm |
| M3 | 3.2mm | 9mm | 0.8mm |
| M3.5 | 3.7mm | 11mm | 0.8mm |
| M4 | 4.3mm | 12mm | 1.0mm |
| M5 | 5.3mm | 15mm | 1.2mm |
| M6 | 6.4mm | 18mm | 1.6mm |
| M7 | 7.4mm | 22mm | 2.0mm |
| M8 | 8.4mm | 24mm | 2.0mm |
| M10 | 10.5mm | 30mm | 2.5mm |
| M12 | 13mm | 37mm | 3.0mm |
| M14 | 15mm | 44mm | 3.0mm |
| M16 | 17mm | 50mm | 3.0mm |
| M18 | 20mm | 56mm | 4.0mm |
| M20 | 22mm | 60mm | 4.0mm |
| M24 | 26mm | 72mm | 5.0mm |
| M30 | 33mm | 92mm | 6.0mm |
| M36 | 39mm | 110mm | 8.0mm |
Materials & strength
Oversized bearing face
An outside diameter of roughly three times the bolt size spreads load across thin or soft material.
Stainless A2 & A4
A2 covers general corrosion resistance, A4 marine and chloride exposure.
What is a penny washer?
A penny washer is a flat washer with an oversized outside diameter - in the DIN 9021 pattern roughly three times the thread diameter - used to spread load over thin, soft or damaged material and to cover oversized holes.
What is the difference between DIN 9021 and DIN 125 washers?
Both are flat washers; DIN 9021 has a much larger outside diameter for the same bolt size, giving a bigger bearing area, while DIN 125 is the compact general-purpose pattern.
What materials are penny washers available in?
Penny washers are available in stainless steel A2 and A4 across a wide range of metric sizes.
Need DIN 9021 in a non-standard size or material?
Send us your drawing — specials quoted within 24 hours.