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Washers · DIN 6798 J · Application guide

What Are Internal Tooth Lock Washers Used For?

Typical applications, the industries that specify internal tooth lock washers, and how to choose the right size, material and finish for the joint.

Internal Tooth Lock Washers are used for resisting loosening by biting into the bearing face and into the joint surface under the head or nut. They are manufactured to DIN 6798 J, and selection is driven by the nominal bolt size, the fit and tolerance the assembly requires, and the service environment.

Primary duty
Resisting loosening by biting into the bearing face and into the joint surface under the head or nut
Governing standard
DIN 6798 J
Nominal bolt size range
M2 to M16
Category
Washers

Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation.

What Are Internal Tooth Lock Washers Used For? application image

The primary duty of Internal Tooth Lock Washers is resisting loosening by biting into the bearing face and into the joint surface under the head or nut. Below: the sectors that specify them in volume, the checklist used to select the right size and material for the application, installation notes, and the known limits of the type. Stocked across roughly M2 to M16, they cover general to heavy-duty work.

Typical Applications for Internal Tooth Lock Washers

The most common settings where these are specified:

  • Vibration applications: spring and serrated types that maintain tension under cyclic load.
  • Timber & soft materials: large-OD types that prevent pull-through.
  • General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
  • Maintenance & repair (MRO): a stocked size for servicing existing plant where the original fastener spec must be matched.
  • Fabrication & metalwork: bench and on-site assembly of steel frames, enclosures and weldments.

How to Specify Internal Tooth Lock Washers for Your Application

  • Size: Match the nominal size to the mating thread or hole. This product spans M2–M16; check the full table below for the exact dimensions of each size.
  • Type & OD: Select flat for load spreading, spring/serrated for anti-loosening, or fender/large-OD for soft or oversized holes.
  • Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
  • Standard: This product is supplied to DIN 6798 J. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

Installation & Assembly Practice

  • Place the washer under the rotating element (usually the nut) so tightening does not score the surface.
  • Chamfered-hole side of a hardened washer faces the bolt head fillet.
  • On serrated-flange hardware, do not add a plain washer — it defeats the serrations.

Common Selection Mistakes with Internal Tooth Lock Washers

  • Relying on a spring washer for locking on class 8.8+ joints — at high preload it flattens and adds nothing.
  • Choosing an OD too small for soft material, so the head pulls through or embeds.

Where Internal Tooth Lock Washers Are Not the Right Choice

A washer does not replace a locking feature on its own in severe vibration, and a spring washer adds little clamp on high-strength joints.

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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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (DIN 6798 J)

SizeInner diameter d1 (mm)Outer diameter d2 (mm)Thickness s (mm)TypeReference standard
M22.24.20.2Internal teethDIN 6798 J
M2.52.75.10.2Internal teethDIN 6798 J
M33.260.2Internal teethDIN 6798 J
M3.53.770.25Internal teethDIN 6798 J
M44.380.25Internal teethDIN 6798 J
M55.39.80.3Internal teethDIN 6798 J
M66.411.80.4Internal teethDIN 6798 J
M88.415.30.4Internal teethDIN 6798 J
M1010.5190.5Internal teethDIN 6798 J
M1213230.5Internal teethDIN 6798 J
M141526.20.6Internal teethDIN 6798 J
M161730.20.6Internal teethDIN 6798 J

Video: What Are Internal Tooth Lock Washers Used For? in use

Toothed Lock Washers - External & Internal | Fasteners 101

Third-party video, selected automatically for this topic. It is not produced by Engineering Hardware and is not a specification source — use the tables on this page for dimensional data.

Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

What material should Internal Tooth Lock Washers be for outdoor use?

For damp, coastal or chemical environments specify A4 (316) stainless or a suitably coated steel. For indoor or dry use, A2 (304) stainless or zinc-plated steel is normally adequate.

Are Internal Tooth Lock Washers made to a recognized standard?

Yes — they are manufactured to DIN 6798 J, so dimensions are interchangeable between suppliers when you quote the standard on your order.

What are Internal Tooth Lock Washers used for?

Resisting loosening by biting into the bearing face and into the joint surface under the head or nut. They are supplied to DIN 6798 J.

Which industries use Internal Tooth Lock Washers?

They are commonly specified in fabrication & metalwork, bolted structural joints and vibration applications, among other sectors.

Can I get a quote for Internal Tooth Lock Washers in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.