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Washers · DIN 6798

M20 Serrated Lock Washers Dimensions & Specifications

M20 Serrated Lock Washers Dimensions & Specifications reference image

M20 is one of the standard coarse-thread sizes for serrated lock washers under DIN 6798. 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 6798)

For sizeInner diameter d1 (mm)Outer diameter d2 (mm)Thickness h (mm)TypeReference standard
M2021.033.01.5Internal-tooth type ADIN 6798 A/J

Spanner & Drive for M20 Serrated Lock Washers

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

Common Applications for M20 Serrated Lock Washers

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

Installation Tips for M20 Serrated Lock 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.

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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 (DIN 6798)

For sizeInner diameter d1 (mm)Outer diameter d2 (mm)Thickness h (mm)TypeReference standard
M33.26.00.5Internal-tooth type ADIN 6798 A/J
M44.37.60.5Internal-tooth type ADIN 6798 A/J
M55.39.20.6Internal-tooth type ADIN 6798 A/J
M66.411.00.7Internal-tooth type ADIN 6798 A/J
M88.414.80.8Internal-tooth type ADIN 6798 A/J
M1010.518.00.9Internal-tooth type ADIN 6798 A/J
M1213.021.51.0Internal-tooth type ADIN 6798 A/J
M1617.027.01.2Internal-tooth type ADIN 6798 A/J
M2021.033.01.5Internal-tooth type ADIN 6798 A/J
M33.27.00.5External-tooth type JDIN 6798 A/J
M44.39.00.5External-tooth type JDIN 6798 A/J
M55.310.00.6External-tooth type JDIN 6798 A/J
M66.412.00.7External-tooth type JDIN 6798 A/J
M88.415.00.8External-tooth type JDIN 6798 A/J
M1010.519.00.9External-tooth type JDIN 6798 A/J
M1213.022.01.0External-tooth type JDIN 6798 A/J
M1617.028.01.2External-tooth type JDIN 6798 A/J
M2021.034.01.5External-tooth type JDIN 6798 A/J

Frequently Asked Questions

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 Serrated Lock Washers?

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

What clearance and tapping drill suit M20?

Use a 22 mm clearance hole (ISO 273 medium) for through-fixing, or a 17.5 mm tapping drill for a coarse M20 thread.

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.