DIN 6798 J Internal Serrated Lock Washers: Engineering & OEM Sourcing Guide

DIN 6798 J internal serrated lock washers are metric serrated washers with inward-facing teeth around the inside diameter. 

They are used beneath compatible screw heads, bolt heads, or nuts where the joint design can benefit from localized serration engagement and additional resistance to relative rotation at the contact interface.

The "J" designation is important. Within the DIN 6798 serrated washer family, 

Form J identifies the internal-serration configuration. It should not be confused with external-serrated washers or Form V countersunk serrated washers.

This distinction matters for both engineering and procurement.

 Two washers may share the same nominal fastener size but have different tooth locations, outside diameters, bearing interfaces, and application constraints.

JUXIN FASTENERS supplies standard and custom washers and fastening components for industrial OEM applications, 

supporting specification-based, drawing-based, and sample-based sourcing.

What Is a DIN 6798 J Internal Serrated Lock Washer?

An internal serrated lock washer has multiple serrations directed inward from the washer body toward its center opening.

When the fastener is tightened, the washer is compressed between the fastener bearing surface and the mating component. 

Depending on material, hardness, coating, geometry, and preload, the serrations can locally engage the contacting surfaces and contribute resistance to relative rotation.

The internal location of the serrations distinguishes Form J from external-serrated washer configurations.

DIN 6798 J is therefore useful as a precise product identifier because "serrated lock washer" alone does not define where the serrations are located.

Internal Serrated vs. External Serrated vs. Conical Serrated Washers

These washer configurations should not be treated as interchangeable.

The correct selection depends on more than thread size.

Fastener-head diameter, bearing surface, available clearance, mating material, coating, and the intended function of the serrations all matter.

DIN 6798 J vs. DIN 6798 V

This distinction is especially important because the two product names can easily become mixed in online catalogs.

DIN 6798 J identifies an internally serrated Form J washer.

DIN 6798 V identifies a countersunk or conical Form V configuration.

Therefore:

J = internal serrations

V = countersunk / conical configuration

An internal serrated washer should not automatically be described as a conical washer, and a Form V washer should not be described as Form J simply because both belong to a serrated washer family.

For procurement teams, including the correct form designation in the RFQ can prevent the wrong geometry from being quoted.

How Does an Internal Serrated Lock Washer Work?

The functional principle is based primarily on surface interaction.

As the threaded fastener is tightened, the washer is compressed between the fastener and mating component. The serrations create localized contact points.

Depending on the actual joint, these contact points can engage the adjacent surfaces and increase resistance to relative rotational movement.

However, the washer should not be described as automatically increasing bolt clamp load.

Clamp load is generated by tightening the threaded fastener and depends on factors such as:

• tightening method;

• fastener geometry;

• thread and bearing friction;

• lubrication;

• coating;

• fastener material;

• joint stiffness;

• installation conditions.

The washer influences the contact interface but does not replace proper preload design.

Does an Internal Serrated Washer Guarantee Against Loosening?

No locking washer should be selected solely on the assumption that its name guarantees that a threaded connection cannot loosen.

Joint behavior depends on the complete fastening system.

Relevant factors include:

• preload;

• transverse movement;

• vibration;

• impact loading;

• thermal cycling;

• joint stiffness;

• mating materials;

• surface hardness;

• coatings;

• lubrication;

• serration geometry;

• installation process.

Internal serrations can contribute resistance to relative rotation, but demanding vibration applications should be evaluated at the joint level.

Where loosening would create a significant safety or reliability risk, engineers should determine whether another validated locking method or an application-specific fastening system is required.

Internal Serrated Washers Are Not Sealing Washers

An important distinction is that DIN 6798 J internal serrated lock washers are not sealing elements.

Their serrated geometry does not create a defined liquid-tight or gas-tight barrier.

They should therefore not be specified by themselves to:

• prevent oil leakage;

• prevent coolant leakage;

• seal against water;

• seal against gas;

• provide pressure sealing;

• provide an IP-rated environmental seal.

If an assembly requires sealing, the sealing function should be designed separately using an appropriate gasket, bonded sealing washer,

 O-ring, sealing compound, elastomeric element, or other application-specific sealing system.

A locking function and a sealing function are different engineering requirements.

This distinction is particularly important when replacing legacy components or reviewing drawings because two washers of similar outside dimensions can perform completely different functions.

Why Internal Serrations Can Be Useful

Placing the serrations toward the center of the washer creates a different contact arrangement from an external-serrated washer.

Depending on the joint geometry, internal serrations can be useful where:

• outside clearance around the fastener is limited;

• the fastener head provides an appropriate bearing interface;

• a more compact washer outside diameter is desirable;

• inward-facing serration engagement suits the assembly;

• external projecting teeth would interfere with surrounding components.

This does not mean internal serrations are universally better.

It means they solve a different geometric problem.

Fastener Head Geometry Matters

The washer should fit beneath the fastener bearing surface without undesirable interference.

Engineers should consider:

• fastener head diameter;

• bearing-face geometry;

• washer inside diameter;

• washer outside diameter;

• serration location;

• available contact area;

• nearby component clearance.

If the fastener head does not adequately interact with the washer, simply matching the nominal thread size may not produce the intended joint.

This is one reason why an existing sample, assembly drawing, or detailed washer specification can be valuable during supplier development.

Mating Surface Condition Matters

Serrated washers work through surface contact.

The same DIN 6798 J washer can interact differently with:

• bare carbon steel;

• plated steel;

• stainless steel;

• aluminum;

• painted steel;

• powder-coated surfaces;

• anodized aluminum;

• hardened components;

• decorative finishes.

Material hardness and coating properties influence how the serrations engage the surface.

Engineers should therefore evaluate the washer together with the actual mating material and finish.

What Happens on Painted or Coated Surfaces?

Internal serrations can locally disturb a coating during tightening.

Depending on the assembly, this may create:

• localized coating penetration;

• cosmetic marking;

• exposure of base metal;

• altered friction conditions;

• changes in corrosion behavior;

• changes in electrical contact.

This can be beneficial in some specific designs and undesirable in others.

For corrosion-sensitive assemblies, coating selection and washer selection should therefore be reviewed as part of the same joint system.

Can Internal Serrated Washers Be Used in Electrical Assemblies?

Internal tooth and serrated washers are commonly encountered in electrical and electronic equipment because their compact geometry

 can suit machine-screw assemblies and other relatively small fastening interfaces.

In some designs, serration engagement may also assist metal-to-metal contact.

However, mechanical fastening and electrical bonding are not automatically the same requirement.

If the joint must provide defined grounding or bonding performance, engineers should consider:

• substrate material;

• plating or coating;

• electrical contact area;

• assembly preload;

• corrosion;

• environmental exposure;

• required resistance;

• applicable equipment requirements.

The completed connection should be validated where electrical continuity is a functional or safety requirement.

Material Selection

DIN 6798 J and drawing-controlled internal serrated washers may be manufactured from different metallic materials depending on the product specification and application.

Common sourcing categories include spring steels and stainless steels.

Spring Steel

Spring-steel washer designs are widely associated with serrated washer applications where formed geometry and mechanical behavior are required.

The actual material grade, processing condition, and hardness should be defined by the applicable specification or customer drawing.

Stainless Steel

Stainless steel may be selected where corrosion resistance or compatibility with stainless assemblies is important.

The exact grade should be specified where material performance is controlled.

Selection should consider:

• corrosion environment;

• mating fastener material;

• substrate material;

• galvanic compatibility;

• mechanical requirements;

• customer specifications.

"Stainless steel" alone may not be sufficient for a controlled OEM component.

Surface Finish and Corrosion Protection

Depending on material and customer requirements, potential finish categories for steel washers can include:

• zinc-based coatings;

• phosphate-based finishes;

• zinc-flake systems;

• nickel-based finishes;

• customer-specified coating systems.

Stainless washers may have material-appropriate surface requirements where specified.

Coating selection should consider more than corrosion resistance.

Because the serrations form functional contact points, coating thickness, hardness, friction, and behavior during installation can affect the interface.

For drawing-controlled components, material and finish should therefore be evaluated together.

Internal Serrated Washer vs. Plain Washer

A plain washer and an internal serrated washer perform different functions.

A plain washer typically provides a bearing surface and can distribute load over a larger area.

An internal serrated washer introduces localized serration engagement.

Therefore, replacing a plain washer with a serrated washer—or replacing a serrated washer with a plain washer—should not be treated as a cosmetic substitution.

The contact mechanics of the joint change.

Internal Serrated Washer vs. Conical Spring Washer

A serrated lock washer should also not be confused with a conical spring washer.

A conical spring washer uses its formed geometry to provide spring behavior under compression.

An internal serrated washer uses serrated contact geometry as a primary distinguishing feature.

Even when two washer types look similar in photographs, their standards, geometry, dimensions, and intended behavior can differ.

For replacement sourcing, product identification should therefore be based on more than appearance.

Can Internal Serrated Lock Washers Be Reused?

Reuse should not automatically be assumed.

During installation, serrations can alter both their own contact condition and the mating surfaces.

After removal, the interface may no longer reproduce the original assembly condition.

Whether reuse is acceptable depends on:

• washer condition;

• permanent deformation;

• serration condition;

• mating-surface condition;

• applicable specification;

• assembly requirements;

• quality-control requirements.

For controlled OEM assembly, replacement with a new washer may provide more predictable conditions where required by the specification or quality plan.

Typical Industrial Applications

Electrical Equipment

Internal serrated washers can be used in suitable machine-screw assemblies, control equipment, electrical cabinets, brackets, housings, and related fastening points.

Where grounding or bonding is required, electrical performance should be evaluated separately.

Industrial Automation

Sensors, brackets, actuators, control assemblies, housings, and machine components can use internal serrated washers where compact geometry and surface engagement suit the joint.

Electronic and Communications Equipment

Electronic enclosures, racks, chassis, equipment cabinets, and mounting systems often contain relatively compact threaded connections where an internal serrated washer may be considered.

Industrial Machinery

Machine guards, brackets, housings, controls, and other equipment assemblies can use Form J washers where the joint geometry and operating conditions are appropriate.

HVAC Equipment

Panels, controls, fan assemblies, brackets, and equipment housings may contain suitable threaded joints.

Material and coating should be selected according to the operating environment.

Automotive and Transportation Components

Internal serrated washers can be considered for suitable brackets, electrical systems, housings, accessories, and other application-specific fastening locations.

They should not automatically be specified for engine sealing, chassis safety joints, or other critical connections merely because vibration is present.

Those applications require their own joint design and validation requirements.

Engineering Selection Framework

A useful selection process starts with the joint rather than the washer catalog.

1. Identify the Required Washer Geometry

Determine whether the application actually needs internal serrations, external serrations, a countersunk Form V washer, a spring washer, or another design.

2. Verify the Fastener Interface

Check nominal thread size, head geometry, bearing diameter, and available contact area.

3. Evaluate the Mating Surface

Consider material, hardness, plating, paint, powder coating, anodizing, and other finishes.

4. Define the Functional Requirement

Determine whether the design requires rotational resistance, compact geometry, electrical contact, load distribution, spring behavior, sealing, or another function.

Do not assume one washer provides all of these functions.

5. Review the Operating Environment

Consider vibration, transverse movement, corrosion, temperature cycling, maintenance, and disassembly.

6. Select Material and Finish

Choose material and coating according to the complete joint and environmental requirements.

7. Validate Critical Functions

Where loosening resistance, electrical continuity, corrosion behavior, or another performance requirement is critical, validation should represent the actual assembly.

Procurement and Supplier-Development Considerations

For sourcing teams, a description such as "internal lock washer" may be too broad for accurate quotation.

Useful information can include:

• DIN 6798 J or applicable customer specification;

• nominal fastener size;

• washer form;

• inside diameter;

• outside diameter;

• thickness;

• material;

• finish or coating;

• mating fastener;

• mating material;

• corrosion requirements;

• drawing or sample;

• inspection requirements;

• packaging requirements;

• order quantity or estimated annual usage.

These factors can influence manufacturing process, tooling, secondary processing, coating, inspection, MOQ, lead time, packaging, and unit cost.

Standard vs. Custom Internal Serrated Washers

Standard DIN 6798 J washers can meet many general requirements, while OEM applications may also require drawing-controlled variants.

Custom development may be appropriate when a project requires:

• non-standard inside diameter;

• modified outside diameter;

• special serration geometry;

• different thickness;

• application-specific material;

• special coating;

• modified bearing interface;

• drawing-controlled tolerances;

• replacement of a proprietary legacy component.

JUXIN FASTENERS supports standard and custom washer sourcing based on customer specifications, drawings, samples, and available application information.

Replacing a Legacy Washer Without a Known Standard

A common procurement problem is having the physical washer but no original standard or drawing.

That can still be a useful starting point.

A sample can help evaluate:

• internal versus external serrations;

• inside diameter;

• outside diameter;

• thickness;

• tooth or serration geometry;

• material;

• coating;

• deformation or formed profile;

• mating fastener.

Photographs with key dimensions can also support an initial review.

This is particularly useful when older equipment documentation uses inconsistent product names.

Making an RFQ Easier

Have a drawing? Send the drawing.

Have a 3D CAD model? Send the available CAD data.

Have an existing washer? We can start from the physical sample.

Only have photographs and a few key dimensions? Those can still provide a useful starting point.

Know that you need DIN 6798 J but have not finalized the material or coating? Send the size, application, mating materials, and environmental requirements currently available.

Still identifying the washer? Send the existing component and mating fastener information.

JUXIN FASTENERS can review the available information and identify which additional technical details may be useful for quotation, manufacturing feasibility review, sample development, or production sourcing.

Frequently Asked Questions

What is a DIN 6798 J washer?

DIN 6798 J is a Form J serrated lock washer with inward-facing serrations around the inside diameter.

What is the difference between an internal and external serrated lock washer?

An internal serrated washer has teeth or serrations directed inward around the center opening. An external serrated washer positions them around the outside region. 

Their bearing geometry and clearance requirements therefore differ.

Is DIN 6798 J a conical washer?

Form J identifies the internal-serration configuration. A countersunk or conical configuration is identified separately as Form V. The two should not be treated as the same washer.

What is the difference between DIN 6798 J and DIN 6798 V?

DIN 6798 J uses internal serrations, while DIN 6798 V is the countersunk or conical form intended for a different fastener interface.

Can an internal serrated lock washer provide a liquid or gas seal?

No sealing performance should be assumed from the serrated washer alone. If liquid, gas, dust, or environmental sealing is required, a dedicated sealing solution should be specified and validated.

Does an internal serrated washer increase clamp load?

It should not be described as automatically increasing clamp load. Clamp load is primarily created by tightening the threaded fastener. The serrations influence the washer's contact interfaces.

Can an internal serrated washer prevent loosening under vibration?

It can contribute resistance to relative rotation, but performance depends on the entire joint, including preload, vibration, transverse movement, mating surfaces, materials, and coatings.

Can internal serrated washers be used for electrical grounding?

They can be used in some electrical assemblies, but a serrated washer alone does not guarantee a compliant grounding or bonding connection.

 Electrical performance should be validated where it is a functional or safety requirement.

Are DIN 6798 J washers reusable?

Reuse should not automatically be assumed because installation can alter the serrations and mating surfaces. 

The applicable specification and assembly requirements should determine whether reuse is acceptable.

Can JUXIN FASTENERS manufacture custom internal serrated washers?

Yes. JUXIN FASTENERS supports drawing-based and sample-based development of custom fastening components. 

Drawings, CAD data, physical samples, photographs, dimensions, or available application information can provide the starting point.

Can I request a quotation if I do not know whether my washer is DIN 6798 J?

Yes. Send the drawing, physical sample, photographs, dimensions, or mating fastener information currently available. 

JUXIN FASTENERS can review the component and identify additional information needed for evaluation.

Source DIN 6798 J Internal Serrated Lock Washers for OEM Applications

Correct washer selection begins by identifying the actual geometry and function of the joint.

DIN 6798 J internal serrated lock washers, external serrated washers, Form V countersunk washers, conical spring washers, plain washers, 

and sealing washers perform different functions and should not be treated as interchangeable components.

For engineering and procurement teams, defining the washer form, fastener interface, mating material, surface coating, operating environment, and required function can significantly improve sourcing accuracy.

JUXIN FASTENERS supports global OEM, ODM, Tier 1, Tier 2, engineering, procurement, sourcing, and supplier-development teams with standard and custom washers and application-specific fastening components.

Whether you have a DIN 6798 J requirement, a customer drawing, an existing physical sample, or only photographs and basic dimensions, send us the information currently available.

We can support technical review, manufacturing feasibility evaluation, sample development, quotation, and production sourcing.

Email: info@juxinfasteners.com

Website: www.juxinfasteners.com