M5 Washer Dimensions & Size
The M5 size is a highly common standard available in three 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 applications with limited radial clearance. Based on these standards, M5 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 clamping force of high-tensile bolts.
Note: While these values reflect standard manufacturer datasheets, actual dimensions and tolerances may vary based on material (e.g., Stainless Steel vs. Nylon) and manufacturing class. Always verify with the official product datasheet for critical applications.
| M5 Standard Series Washer – DIN 125A/ISO 7089 | ||
|---|---|---|
| Dimension | Size (mm) | |
| Min | Max | |
| Inner Diameter | 5.3 | 5.48 |
| Outside Diameter | 9.64 | 10 |
| Thickness | 0.9 | 1.1 |
| M5 Large Series Washer – DIN 9021/ISO 7093 | ||
|---|---|---|
| Dimension | Size (mm) | |
| Min | Max | |
| Inner Diameter | 5.3 | 5.48 |
| Outside Diameter | 14.57 | 15 |
| Thickness | 1 | 1.4 |
| M5 Small Series Washer – DIN 433/ISO 7092 | ||
|---|---|---|
| Dimension | Size (mm) | |
| Min | Max | |
| Inner Diameter | 5.3 | 5.48 |
| Outside Diameter | 8.64 | 9 |
| Thickness | 0.9 | 1.1 |
- 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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|---|---|
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Frequently Asked Questions
What does the “M5” designation mean on a washer?
The “M” stands for Metric, and the number represents the nominal thread diameter of the screw or bolt. An M5 washer is designed specifically for fasteners with a 5 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) M5 washer?
The Large Series (DIN 9021 / ISO 7093) features a significantly wider outside diameter, roughly three times the nominal thread size. It is used when fastening into soft materials like plastics, composites, or wood, where you need to spread the clamping load over a wider area to prevent the fastener head from crushing or pulling through the material.
What does the HV rating mean on a washer?
HV stands for Vickers Hardness. For M5 fasteners, a rating of 200 HV or 300 HV is standard for steel and stainless steel. This rating ensures the washer maintains its flatness and resists indentation when tightened to the torque levels required for secure mechanical fastening.
What is the difference between Small Series (DIN 433) and Normal Series?
The Small Series (DIN 433 / ISO 7092) has a narrower outside diameter compared to the Normal Series (DIN 125A / ISO 7089). It is intended for use with cylindrical head screws or in recessed areas where a standard-sized washer would be too wide to fit.
In which materials are M5 washers commonly available?
M5 washers are most frequently produced in A2 (304) and A4 (316) Stainless Steel for excellent corrosion resistance. They are also widely available in Zinc-Plated Steel for cost-effective general use and Nylon 66 for non-conductive electrical applications.