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Washers · DIN 9021

M20 Fender Washers Dimensions & Specifications

M20 Fender Washers Dimensions & Specifications reference image

M20 is one of the standard coarse-thread sizes for fender washers under DIN 9021. The sections below reproduce the dimensional row, list the matching tools and hole sizes, and summarize where this size is normally specified.

M20 Dimensional Row (DIN 9021)

For bolt sizeInner diameter d1 min (mm)Outer diameter d2 max (mm)Thickness h (mm)Reference standardNotes
M2021.060.04.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials

Spanner & Drive for M20 Fender Washers

Drive geometry for M20 Fender Washers is given by the row above; match the tool to the listed values.

Common Applications for M20 Fender Washers

M20 Fender Washers are commonly specified for high-load load-spreading on structural joints.

Installation Tips for M20 Fender Washers

  • At M20 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 M20

A M20 flat washer pairs with a M20 bolt/screw and matching M20 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 (DIN 9021)

For bolt sizeInner diameter d1 min (mm)Outer diameter d2 max (mm)Thickness h (mm)Reference standardNotes
M33.29.00.8DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M44.312.01.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M55.315.01.2DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M66.418.01.6DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M88.424.02.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M1010.530.02.5DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M1213.037.03.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M1415.044.03.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M1617.050.03.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M2021.060.04.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M2425.072.05.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M3031.090.06.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials
M3637.0110.08.0DIN 9021 / ISO 7093Oversized OD for bearing on soft materials

Frequently Asked Questions

Should M20 Fender Washers be tightened by torque or by angle?

For critical structural joints at M20, 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 M20 structural bolts?

Grip ranges are highly application-dependent at M20. 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 M20?

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.

What is the coarse-thread pitch of M20 for Fender Washers?

For M20 the standard coarse pitch is 2.5 mm — this is the value used for Fender Washers.

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.