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Washers · ISO 7089 / ISO 7093

M4 Flat Washers Dimensions & Specifications

M4 Flat Washers Dimensions & Specifications reference image

M4 Flat Washers are manufactured to ISO 7089 / ISO 7093 with a coarse thread pitch of 0.7 mm. This page lists the controlling dimensions for the M4 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.

M4 Dimensional Row (ISO 7089 / ISO 7093)

For bolt sizeInner diameter d1 min (mm)Outer diameter d2 max (mm)Thickness h (mm)Reference standard
M44.39.00.8ISO 7089

Spanner & Drive for M4 Flat Washers

Drive geometry for M4 Flat Washers is given by the row above; match the tool to the listed values.

Common Applications for M4 Flat Washers

M4 Flat Washers are commonly specified for small electronics hardware and precision assemblies.

Mating Parts for M4

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

When to Step Up or Down from M4

When the joint preload approaches the proof load of M4 class 8.8, step up to M5 class 8.8 (or move to M4 class 10.9). When the joint is over-specified, M3 often saves weight and cost without losing the safety margin.

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 (ISO 7089 / ISO 7093)

For bolt sizeInner diameter d1 min (mm)Outer diameter d2 max (mm)Thickness h (mm)Reference standard
M1.61.74.00.3ISO 7089
M22.25.00.3ISO 7089
M2.52.76.00.5ISO 7089
M33.27.00.5ISO 7089
M3.53.78.00.5ISO 7089
M44.39.00.8ISO 7089
M55.310.01.0ISO 7089
M66.412.01.6ISO 7089
M77.414.01.6ISO 7089
M88.416.01.6ISO 7089
M1010.520.02.0ISO 7089
M1213.024.02.5ISO 7089
M1415.028.02.5ISO 7089
M1617.030.03.0ISO 7089
M1819.034.03.0ISO 7089
M2021.037.03.0ISO 7089
M2223.039.03.0ISO 7089
M2425.044.04.0ISO 7089
M2728.050.04.0ISO 7089
M3031.056.04.0ISO 7089
M3334.060.05.0ISO 7089
M3637.066.05.0ISO 7089
M3940.072.06.0ISO 7089
M4243.078.07.0ISO 7089
M4546.085.07.0ISO 7089
M4850.092.08.0ISO 7089
M5254.098.08.0ISO 7089
M5658.0105.09.0ISO 7089
M6062.0110.09.0ISO 7089
M6466.0115.09.0ISO 7089
M55.315.01.0ISO 7093 large series
M66.418.01.6ISO 7093 large series
M88.424.02.0ISO 7093 large series
M1010.530.02.5ISO 7093 large series
M1213.037.03.0ISO 7093 large series
M1617.050.03.0ISO 7093 large series
M2021.060.04.0ISO 7093 large series
M2425.072.05.0ISO 7093 large series

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 Flat Washers suitable for electronics and small mechanisms?

M4 Flat Washers 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.