M10 Washer Dimensions & Size
The M10 size is available in three versatile series: the Normal Series (DIN 125A / ISO 7089) for standard load distribution, the Large Series (DIN 9021 / ISO 7093) for increased surface area, and the Small Series (DIN 433 / ISO 7092) for tight radial clearances. Based on these standards, M10 washers typically feature a hardness of 200 HV or 300 HV (Vickers Hardness), providing the structural integrity required to prevent “cupping” or deformation under the significant clamping forces of grade 8.8, 10.9, or 12.9 bolts.
Note: While these values reflect standard manufacturer datasheets, actual dimensions and tolerances may vary based on material (e.g., Stainless Steel vs. Galvanized Steel) and manufacturing class. Always verify with the official product datasheet for critical applications.
| M10 Standard Series Washer – DIN 125A/ISO 7089 | ||
|---|---|---|
| Dimension | Size (mm) | |
| Min | Max | |
| Inner Diameter | 10.5 | 10.77 |
| Outside Diameter | 19.48 | 20 |
| Thickness | 1.8 | 2.2 |
| M10 Large Series Washer – DIN 9021/ISO 7093 | ||
|---|---|---|
| Dimension | Size (mm) | |
| Min | Max | |
| Inner Diameter | 10.5 | 10.77 |
| Outside Diameter | 29.48 | 30 |
| Thickness | 2.3 | 2.7 |
| M10 Small Series Washer – DIN 433/ISO 7092 | ||
|---|---|---|
| Dimension | Size (mm) | |
| Min | Max | |
| Inner Diameter | 10.5 | 10.77 |
| Outside Diameter | 17.57 | 18 |
| Thickness | 1.4 | 1.8 |
- Inner Diameter – The diameter of the hole, designed to clear the bolt/screw thread.
- Outside Diameter – The total width of the washer, determining the load distribution area.
- Thickness – The height of the washer, providing the spacing and structural support.
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Frequently Asked Questions
What does the “M10” designation mean on a washer?
The “M” stands for Metric, and the number represents the nominal thread diameter of the screw or bolt. An M10 washer is designed specifically for fasteners with a 10 mm nominal major diameter.
What is the difference between Form A and Form B washers?
The difference lies in the outer edge finish. Form A washers have a square, flat edge and are the most common. Form B washers include a 30° to 40° chamfer (beveled edge) on one side, according to DIN 125B and ISO 7090 standards.
When should I use a Large Series (DIN 9021) M10 washer?
The Large Series (DIN 9021 / ISO 7093) features a significantly wider outside diameter of 30 mm, which is exactly three times the nominal thread size. It is used when fastening into soft materials like wood, fiberglass, or oversized holes in sheet metal, where the clamping load must be spread over a maximum area to prevent pull-through.
What does the HV rating mean on a washer?
HV stands for Vickers Hardness. For M10 fasteners, a rating of 200 HV or 300 HV is standard for steel and stainless steel. This ensures the washer maintains its structural integrity and flatness even when subjected to the high torque levels required for heavy mechanical joints.
What is the difference between Small Series (DIN 433) and Normal Series?
The Small Series (DIN 433 / ISO 7092) has a narrower outside diameter (18 mm) compared to the Normal Series (20 mm). It is specifically intended for use with Socket Head Cap Screws or in recessed counterbores where space is limited and a standard washer would be too wide.
In which materials are M10 washers commonly available?
M10 washers are most frequently produced in A2 (304) and A4 (316) Stainless Steel for corrosion resistance. They are also widely available in Hot-Dip Galvanized Steel for outdoor construction and Zinc-Plated Steel for general industrial use.