Form D Flat Washers
M6 - M24
Steel zinc platedA2 stainless steelA4 stainless steel
Form D flat washers are an extra-wide flat washer pattern used to spread load over weak or oversized holes. We supply Form D washers across a range of metric sizes.
Also known as: BS 4320 form D, repair washers, mudguard washers.
Form D Washers dimensions
| Bolt Size | Inside Diameter | Outside Diameter | Thickness |
|---|---|---|---|
| M6 | 6.4mm | 14.0mm | 0.8mm |
| M8 | 8.4mm | 21mm | 1.0mm |
| M10 | 10.5mm | 24mm | 1.25mm |
| M12 | 13mm | 28mm | 1.6mm |
| M14 | 15mm | 30mm | 1.6mm |
| M16 | 17mm | 34mm | 2.0mm |
| M18 | 19mm | 37mm | 2.0mm |
| M20 | 21mm | 39mm | 2.0mm |
| M24 | 25mm | 50mm | 2.5mm |
Materials & strength
Extra-wide bearing face
The oversized outside diameter suits repair work and load spreading on weak materials.
Frequently asked
What is a Form D washer used for?
Form D washers carry a much larger outside diameter than standard flat washers, spreading load over soft, thin or damaged surfaces and covering oversized or elongated holes.
Which sizes are covered?
The dimensions table lists the Form D range we cover. Send us your requirement and we can identify the appropriate washer.
Need Form D Washers in a non-standard size or material?
Send us your drawing — specials quoted within 24 hours.