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Washers · GB/T 97.1 / ISO 7089

M18 Flat Plain Washer (GB/T 95) Dimensions & Specifications

M18 Flat Plain Washer (GB/T 95) Dimensions & Specifications reference image

This page covers M18 Flat Plain Washer (GB/T 95) to GB/T 97.1 / ISO 7089: the full dimensional row, hole and tool sizes, proof-load data and typical applications. All values are taken from the governing standards (GB/T 97.1 / ISO 7089 together with ISO 273, ISO 724 and ISO 898-1 where applicable).

M18 Dimensional Row (GB/T 97.1 / ISO 7089)

For bolt sizeInner diameter d1 (mm)Outer diameter d2 (mm)Thickness t (mm)Reference standard
M1819.034.03.0ISO 7089 / GB/T 97.1

Spanner & Drive for M18 Flat Plain Washer (GB/T 95) — GB/T 97.1 / ISO 7089 (Series 086)

Drive geometry for M18 Flat Plain Washer (GB/T 95) — GB/T 97.1 / ISO 7089 (Series 086) is given by the row above; match the tool to the listed values.

Common Applications for M18 Flat Plain Washer (GB/T 95) — GB/T 97.1 / ISO 7089 (Series 086)

M18 Flat Plain Washer (GB/T 95) — GB/T 97.1 / ISO 7089 (Series 086) are commonly specified for high-load load-spreading on structural joints.

Installation Tips for M18 Flat Plain Washer (GB/T 95) — GB/T 97.1 / ISO 7089 (Series 086)

  • At M18 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.

Mating Parts for M18

A M18 flat washer pairs with a M18 bolt/screw and matching M18 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.

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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 97.1 / ISO 7089)

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 M18?

Use a 20 mm clearance hole (ISO 273 medium) for through-fixing, or a 15.5 mm tapping drill for a coarse M18 thread.

Should M18 Flat Plain Washer (GB/T 95) — GB/T 97.1 / ISO 7089 (Series 086) be tightened by torque or by angle?

For critical structural joints at M18, angle-controlled or stretch-controlled tightening is more repeatable than pure torque — the friction scatter at large diameters can dominate the torque signal.

What grip range is typical for M18 structural bolts?

Grip ranges are highly application-dependent at M18. As a guide, choose a length that gives at least 1× the thread diameter engagement in the nut plus 2–3 thread pitches projecting.

Which washer dimensions matter most for M18?

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.