M2 Washer Dimensions & Size

M2 washer dimensions are standardized for high-precision applications, including consumer electronics, 3D printer assembly, drone manufacturing (FPV), and micro-robotics. Specifically designed for fasteners with a 2 mm nominal diameter, these components ensure stable load distribution and protect mating surfaces from damage during tightening. This chart covers Form A plain washers, which feature a flat surface without a chamfer (unlike Form B).

This size is available in two standardized series: the Normal Series and the Small Series. Consequently, this chart includes data based on DIN 125A / ISO 7089 for standard profiles and DIN 433 / ISO 7092 for small series washers. Based on these standards, M2 washers typically feature a hardness of 200 HV or 300 HV (Vickers Hardness), providing the necessary structural integrity to prevent deformation under the clamping force of high-tensile bolts used in PCB mounting and mechanical housings.

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.

Washer dimension diagram showing inner diameter, outside diameter, and thickness
M2 Standard Series Washer – DIN 125A/ISO 7089
Dimension Size (mm)
Min Max
Inner Diameter 2.2 2.34
Outside Diameter 4.7 5
Thickness 0.25 0.35
M2 Small Series Washer – DIN 433/ISO 7092
Dimension Size (mm)
Min Max
Inner Diameter 2.2 2.34
Outside Diameter 4.2 4.5
Thickness 0.25 0.35
  • 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 “M2” designation mean on a washer?

The “M” stands for Metric, and the number represents the nominal thread diameter of the screw or bolt the washer is intended to fit. An M2 washer is designed specifically for fasteners with a 2 mm nominal major diameter.

What does the HV rating mean on a washer?

HV stands for Vickers Hardness. It is a measurement of the material’s resistance to indentation. For M2 fasteners, a rating of 200 HV or 300 HV is standard for steel and stainless steel, ensuring the washer maintains its shape under high torque.

What is the difference between Form A and Form B washers?

The difference lies in the outer edge. Form A washers have a square, flat edge. Form B washers include a 30° to 40° chamfer (beveled edge) on one side, according to DIN 125B and ISO 7090 standards, often used for a cleaner aesthetic or to prevent snagging.

When should I use a Small Series (DIN 433) M2 washer?

Small Series (DIN 433) washers have a smaller outside diameter (OD) than standard washers. They are used when space is extremely limited, such as in recessed holes or on densely packed circuit boards where a standard M2 washer might touch neighboring components.

In which materials are M2 washers commonly available?

M2 washers are most commonly produced in A2 (304) and A4 (316) Stainless Steel. They are also widely available in Nylon for non-conductive electronic applications and Black Oxide finishes for stealthy looks in RC hobbyist gear.