Form C Flat Washers
M4 - M24
Steel zinc platedA2 stainless steelA4 stainless steel
Form C flat washers are a wider-diameter flat washer pattern, giving more bearing area than Form A or B at the same bolt size. We supply Form C washers across a range of metric sizes.
Also known as: BS 4320 form C, repair washers.
Form C Washers dimensions
| Bolt Size | Inside Diameter | Outside Diameter | Thickness |
|---|---|---|---|
| M4 | 4.2mm | 10mm | 0.8mm |
| M5 | 5.3mm | 12.5mm | 1.0mm |
| M6 | 6.4mm | 14.0mm | 1.6mm |
| M8 | 8.4mm | 21mm | 1.6mm |
| M10 | 10.5mm | 24mm | 2.0mm |
| M12 | 13mm | 28mm | 2.5mm |
| M14 | 15mm | 30mm | 2.5mm |
| M16 | 17mm | 34mm | 3.0mm |
| M18 | 19mm | 37mm | 3.0mm |
| M20 | 21mm | 39mm | 3.0mm |
| M24 | 25mm | 50mm | 4.0mm |
Materials & strength
Wide bearing face
The enlarged outside diameter spreads clamping load over a greater area than a standard flat washer.
Frequently asked
What is a Form C washer?
Form C is a flat washer pattern with a larger outside diameter than the standard Form A, used where load needs spreading over a wider area, such as softer or thinner materials.
Which sizes are covered?
The dimensions table lists the Form C range we cover, from M5 upward. Send us your requirement and we can identify the appropriate washer.
Need Form C Washers in a non-standard size or material?
Send us your drawing — specials quoted within 24 hours.