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Washers · GB/T 97.2 / ISO 7090

M4 General Flat Washer Dimensions & Specifications

M4 General Flat Washer Dimensions & Specifications reference image

M4 is one of the standard coarse-thread sizes for general flat washer under GB/T 97.2 / ISO 7090. The sections below reproduce the dimensional row, list the matching tools and hole sizes, and summarize where this size is normally specified.

M4 Dimensional Row (GB/T 97.2 / ISO 7090)

For bolt sizeInner diameter d1 (mm)Outer diameter d2 (mm)Thickness t (mm)Reference standard
M44.39.00.8ISO 7089 / GB/T 97.1

Spanner & Drive for M4 General Flat Washer — GB/T 97.2 / ISO 7090 (Series 088)

Drive geometry for M4 General Flat Washer — GB/T 97.2 / ISO 7090 (Series 088) is given by the row above; match the tool to the listed values.

Common Applications for M4 General Flat Washer — GB/T 97.2 / ISO 7090 (Series 088)

M4 General Flat Washer — GB/T 97.2 / ISO 7090 (Series 088) are commonly specified for small electronics hardware and precision assemblies.

Installation Tips for M4 General Flat Washer — GB/T 97.2 / ISO 7090 (Series 088)

  • At M4 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.

Mating Parts for M4

A M4 flat washer pairs with a M4 bolt/screw and matching M4 nut.

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

Request a Quote

Adjust the parameters in the drawing above and click "Request this configuration" to send the exact specification straight to this form.

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Specification
Business Information

Dimensions & Specifications (GB/T 97.2 / ISO 7090)

For bolt sizeInner diameter d1 (mm)Outer diameter d2 (mm)Thickness t (mm)Reference standard
M33.27.00.5ISO 7089 / GB/T 97.1
M44.39.00.8ISO 7089 / GB/T 97.1
M55.310.01.0ISO 7089 / GB/T 97.1
M66.412.01.6ISO 7089 / GB/T 97.1
M88.416.01.6ISO 7089 / GB/T 97.1
M1010.520.02.0ISO 7089 / GB/T 97.1
M1213.024.02.5ISO 7089 / GB/T 97.1
M1415.028.02.5ISO 7089 / GB/T 97.1
M1617.030.03.0ISO 7089 / GB/T 97.1
M1819.034.03.0ISO 7089 / GB/T 97.1
M2021.037.03.0ISO 7089 / GB/T 97.1
M2425.044.04.0ISO 7089 / GB/T 97.1
M3031.056.04.0ISO 7089 / GB/T 97.1
M3637.066.05.0ISO 7089 / GB/T 97.1

Frequently Asked Questions

What clearance and tapping drill suit M4?

Use a 4.5 mm clearance hole (ISO 273 medium) for through-fixing, or a 3.3 mm tapping drill for a coarse M4 thread.

Is M4 General Flat Washer — GB/T 97.2 / ISO 7090 (Series 088) suitable for electronics and small mechanisms?

M4 General Flat Washer — GB/T 97.2 / ISO 7090 (Series 088) is in the micro range and is widely used in electronics, instrument enclosures and small precision mechanisms. Watch the over-torque margin — micro joints strip easily.

What's the typical proof load behavior of M4 class 8.8?

Micro-thread joints are sensitive to plastic deformation in the first turn under load — use a torque-limiting driver and check the bearing surface deformation on softer mating materials.

Which washer dimensions matter most for M4?

For a flat washer, the outside diameter (the bearing surface) and the thickness control how the load is spread under the head and how much elastic preload is preserved. The inside diameter must clear the bolt body but not be so large that the head bears mostly on the washer's outer rim.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.