Stainless Steel Locknuts with External-Tooth Lock Washer

Stainless Steel Locknuts with External-Tooth Lock Washer

Corrosion-Resistant Stainless Steel Keps Nuts and K-Lock Nuts for OEM Industrial Manufacturing

Juxin Fasteners manufactures stainless steel locknuts with external-tooth lock washers for industrial OEM applications requiring corrosion-resistant fastening components, 

convenient assembly and integrated washer retention.

Also known as stainless steel Keps nuts or K-Lock nuts, these fasteners combine an internally threaded hex nut with a captive, free-spinning external-tooth lock washer.

The washer remains attached to the nut during handling and installation, reducing the need to position a separate locking washer.

When tightened against a compatible mating surface, the external teeth engage the bearing surface and provide additional resistance to rotation.

This locking mechanism is suitable for selected industrial assemblies requiring efficient installation and mild resistance to loosening.

Unlike nylon-insert or all-metal prevailing-torque locknuts, conventional Keps nuts do not rely on a locking feature within the internal thread.

Juxin Fasteners supports OEM/ODM manufacturing, drawing-based customization, stainless steel material evaluation, dimensional inspection and industrial batch production.

Product Technical Specifications

Engineering Note: Actual material grades, washer material, mechanical properties, dimensional tolerances, 

surface finishing and corrosion requirements must be confirmed against the approved engineering drawing.

The thread range describes the supplied product family. Individual size and material combinations require confirmation.

How Stainless Steel Keps Nuts Work

A stainless steel Keps nut combines a hexagonal internally threaded nut with a captive external-tooth washer.

Before final tightening, the washer can rotate relative to the nut.

This allows the nut to be threaded onto a compatible bolt or stud without the locking washer immediately resisting rotation against the mating surface.

Once the washer contacts the bearing surface, further tightening compresses the toothed washer.

The teeth engage the surface and create additional resistance to relative movement.

The locking function depends on:

• Washer tooth geometry.

• Washer material and hardness.

• Installation torque.

• Joint preload.

• Mating surface hardness.

• Surface coating.

• Contact conditions.

• Mechanical loading.

• Vibration exposure.

The teeth primarily engage the mating bearing surface rather than the threaded rod.

The effectiveness of this mechanism must be evaluated for the intended joint.

Advantages of Stainless Steel Captive Washer Nuts

Corrosion Resistance

Stainless steel offers corrosion resistance through its chromium-rich passive surface film.

The actual corrosion performance depends on alloy composition, surface condition and service environment.

Integrated Washer Retention

The captive washer remains associated with the nut during normal handling and installation, provided the retention feature remains intact.

This reduces the need to manage separate washers.

Convenient Assembly

The free-spinning washer allows the nut to be positioned before final tightening.

This can simplify repetitive assembly operations.

Material Selection Flexibility

Different stainless steel grades can be evaluated for corrosion resistance, mechanical requirements and manufacturing feasibility.

OEM Customization

Customer-specific dimensions, thread configurations, washer geometry and surface finishing requirements can be reviewed for industrial batch manufacturing.

18-8 Stainless Steel Keps Nuts

18-8 stainless steel is a common American industrial fastener material designation associated with chromium-nickel austenitic stainless steels.

It is frequently used for fasteners requiring corrosion resistance in many indoor, humid and outdoor environments.

AISI 304 is a common material option within this general material category.

Potential applications include:

• Electrical equipment.

• Industrial cabinets.

• Appliance assemblies.

• Telecommunications equipment.

• Indoor machinery.

• Selected outdoor equipment.

• Stainless steel mechanical brackets.

18-8 stainless steel should not automatically be assumed suitable for aggressive chloride exposure or highly corrosive chemical environments.

Material selection must account for the actual operating conditions.

AISI 304 Stainless Steel Keps Nuts

AISI 304 stainless steel is widely used for industrial fasteners and fabricated equipment components.

Its corrosion resistance makes it relevant to many general industrial applications.

Engineering considerations include:

• Atmospheric corrosion exposure.

• Moisture.

• Cleaning chemicals.

• Thread strength.

• Washer material compatibility.

• Surface finish.

• Manufacturing feasibility.

• Assembly conditions.

304 Stainless Steel and A2-70 Are Not Automatically Equivalent Product Specifications

AISI 304 identifies a stainless steel material grade.

A2-70 is a fastener property designation associated with defined material and mechanical property requirements under applicable standards.

A product manufactured from 304 stainless steel should not automatically be described as A2-70 unless the applicable mechanical properties and requirements have been verified.

For custom Keps nuts, the required material grade and mechanical property designation must be confirmed separately.

AISI 316 Stainless Steel Keps Nuts

AISI 316 stainless steel contains molybdenum and generally offers improved resistance to certain chloride-containing environments compared with AISI 304.

This may make it relevant for selected outdoor, coastal, chemical processing and marine-related equipment applications.

Potential applications include:

• Coastal equipment enclosures.

• Outdoor electrical cabinets.

• Selected chemical equipment.

• Marine accessory brackets.

• Industrial washdown equipment.

• Corrosion-exposed mechanical assemblies.

However, AISI 316 is not immune to corrosion.

Pitting, crevice corrosion and stress corrosion cracking can occur under unfavorable environmental conditions.

Marine and chemical applications require review of chloride concentration, temperature, crevice conditions, cleaning agents and mechanical loading.

The availability and suitability of a complete 316 stainless steel Keps nut assembly must be evaluated, including the captive washer material.

Stainless Steel Material Selection

The selected material must be compatible with the nut geometry, washer design and intended application.

Captive Washer Material and Hardness

The external-tooth washer is a functional component of the locking mechanism.

The washer may require different mechanical properties from the hex nut body.

Important characteristics include:

• Material grade.

• Hardness.

• Spring characteristics.

• Tooth profile.

• Washer thickness.

• Tooth deformation.

• Washer retention.

• Corrosion compatibility.

• Surface finish.

A washer manufactured from the same stainless steel grade as the nut does not automatically provide the required tooth engagement performance.

In some designs, a harder stainless steel or another suitable spring material may be required.

The actual washer material and hardness should be defined by the customer-approved specification.

Corrosion Compatibility Between Nut and Washer

For stainless steel captive washer nuts, corrosion resistance must be evaluated for the complete assembly.

The nut body and washer may have different alloy compositions or surface conditions.

Potential engineering considerations include:

• Galvanic compatibility.

• Crevice corrosion.

• Chloride exposure.

• Moisture retention.

• Washer-to-nut contact.

• Surface contamination.

• Passivation requirements.

• Cleaning processes.

A corrosion-resistant nut body does not guarantee that every component of the assembled fastener has identical corrosion performance.

Stainless Steel Surface Finish Options

Natural Stainless Steel Finish

Natural stainless steel provides a metallic appearance without requiring conventional zinc plating.

Surface condition and manufacturing residues should be controlled according to the application requirements.

Pickled Stainless Steel

Pickling may be specified to remove certain surface oxides or contamination after manufacturing.

The process must be suitable for the selected stainless steel grade and finished component geometry.

Passivated Stainless Steel

Passivation may be specified to improve surface cleanliness and support the formation or restoration of the passive surface condition.

The applicable treatment should be defined by the customer specification.

Polished Stainless Steel

Polishing may be considered where appearance, surface finish or cleaning requirements are important.

The required surface roughness and finish quality should be established through the engineering specification.

Special Surface Treatments

Other finishes may be evaluated for specific OEM requirements.

The treatment must be compatible with the captive washer, internal thread and intended corrosion performance.

Metric Stainless Steel Keps Nuts — M3 to M12

Juxin Fasteners supports metric configurations within the supplied M3–M12 stainless steel product range.

These are common ISO metric coarse-thread specifications.

Actual washer dimensions, nut height, thread tolerances and material availability must be confirmed for each configuration.

Custom metric thread requirements may be evaluated for OEM manufacturing.

Unified Inch-Thread Stainless Steel Keps Nuts

American OEM manufacturers frequently specify Unified inch-thread captive washer nuts.

The following thread designations are included in the supplied product range.

Additional inch-thread configurations may be evaluated according to customer drawings.

UNF Fine-Thread Configurations

Potential customer-specific UNF requirements include:

These additional configurations are subject to manufacturing feasibility review and are not presented as confirmed standard inventory.

Metric and Unified inch threads are not interchangeable.

Thread diameter, pitch, tolerance and mating bolt compatibility must be verified before manufacturing or assembly.

Dimensional Engineering for Stainless Steel Keps Nuts

The nut and captive washer must be designed as a functional assembly.

Important dimensions include:

• Thread designation.

• Internal thread tolerance.

• Hex width across flats.

• Nut body height.

• Overall height with washer.

• Washer outside diameter.

• Washer thickness.

• Tooth quantity.

• Tooth geometry.

• Washer retention dimensions.

• Washer rotational clearance.

The washer must remain attached during normal handling while retaining the required movement before final tightening.

The assembled height should include the captive washer where specified by the product drawing.

Electrical Enclosures and Control Cabinets

Stainless steel Keps nuts may be evaluated for mechanical fastening in electrical equipment exposed to moisture or requiring corrosion-resistant components.

Potential applications include:

• Electrical cabinet brackets.

• Control enclosure accessories.

• Equipment mounting panels.

• Stainless steel cabinet assemblies.

• Industrial control equipment.

• Outdoor enclosure hardware.

The toothed washer may mark or penetrate the mating surface finish.

Electrical bonding and grounding requirements must be independently evaluated according to the equipment design and applicable standards.

Telecommunications and Data Center Equipment

Stainless steel captive washer nuts may be suitable for selected telecommunications equipment and cabinet assemblies.

Potential applications include:

• Telecommunications cabinet brackets.

• Network equipment housings.

• Server cabinet accessories.

• Cable management supports.

• Outdoor communication enclosures.

• Mechanical mounting panels.

Material selection should account for humidity, maintenance requirements and the actual installation environment.

Medical Equipment Manufacturing

Medical equipment manufacturers may require corrosion-resistant fastening components for selected non-patient-contact mechanical assemblies.

Potential applications include:

• Equipment housing brackets.

• Instrument cabinet components.

• Mechanical support panels.

• Serviceable equipment accessories.

• Non-critical enclosure assemblies.

The use of stainless steel alone does not establish medical-device compliance, biocompatibility or suitability for sterilization.

Such requirements must be evaluated separately according to the specific application.

Food Processing and Washdown Equipment

Stainless steel Keps nuts may be evaluated for selected non-product-contact equipment components in food processing environments.

Potential applications include:

• Equipment enclosure brackets.

• Control cabinet accessories.

• Mechanical support structures.

• Washdown-area equipment housings.

Material selection should consider cleaning chemicals, moisture exposure, corrosion and hygienic design requirements.

A captive washer assembly may create crevices that are unsuitable for certain hygienic or direct food-contact applications.

Suitability must be established through equipment-specific engineering review.

Chemical Processing Equipment

Chemical equipment manufacturers may require stainless steel fastening components for selected auxiliary assemblies.

Potential applications include:

• Equipment cabinet brackets.

• Instrument housings.

• Mechanical support panels.

• Control equipment accessories.

Chemical compatibility depends on the exact process environment.

AISI 304 or 316 should not automatically be considered suitable for all acids, alkalis, solvents or industrial chemicals.

Marine and Coastal Equipment

Selected stainless steel Keps nut configurations may be evaluated for coastal or marine-related equipment where corrosion resistance is important.

Potential applications include:

• Coastal electrical enclosures.

• Marine equipment cabinets.

• Non-critical accessory brackets.

• Instrument mounting structures.

• Protected mechanical equipment assemblies.

The suitability of AISI 316 or other stainless steel grades must be assessed according to chloride exposure, crevice conditions and service requirements.

These products should not automatically be specified for critical marine structural connections or continuous seawater immersion.

Automotive and EV Auxiliary Equipment

Automotive manufacturers may evaluate stainless steel captive washer nuts for selected non-critical assemblies requiring corrosion resistance.

Potential applications include:

• Auxiliary equipment brackets.

• Interior equipment housings.

• Electrical accessory enclosures.

• Serviceable mechanical components.

• Selected EV equipment cabinets.

Vibration, temperature, corrosion and mechanical loading must be evaluated for the specific application.

Conventional Keps nuts should not automatically replace qualified prevailing-torque fasteners in demanding automotive joints.

Industrial Motors and Machinery

Stainless steel Keps nuts may be considered for selected motor accessories, machinery housings and equipment brackets.

Potential applications include:

• Motor accessory brackets.

• Machinery covers.

• Equipment support panels.

• Mechanical control housings.

• Serviceable industrial assemblies.

For vibration-intensive equipment, the fastening method must be selected according to validated joint requirements.

Outdoor Lighting and Electrical Infrastructure

Stainless steel captive washer nuts may be evaluated for selected outdoor lighting and electrical equipment assemblies.

Potential applications include:

• Lighting enclosure brackets.

• Electrical equipment housings.

• Instrument mounting components.

• Outdoor cabinet accessories.

• Non-critical mechanical supports.

Corrosion exposure, temperature variation and long-term service requirements should be considered.

Structural and safety-critical applications require appropriate qualification.

Agricultural and Construction Equipment

Selected stainless steel Keps nuts may be used in auxiliary equipment components where moisture and environmental exposure are relevant.

Potential applications include:

• Equipment covers.

• Control housings.

• Accessory brackets.

• Non-critical enclosure components.

Heavy vibration, shock loading and structural joint requirements may necessitate a different locking system.

Installation Guidelines

A typical installation process includes:

1. Confirming the nut and mating bolt thread specifications.

2. Inspecting the captive washer.

3. Checking the bearing surface.

4. Positioning the nut on the bolt or stud.

5. Threading the nut until the washer contacts the surface.

6. Tightening with the appropriate tool.

7. Applying the specified installation torque.

8. Inspecting final seating and joint condition.

Installation torque must be established according to material grade, thread condition, lubrication, washer design and joint requirements.

Stainless steel threaded assemblies may be susceptible to galling.

Appropriate thread condition, installation speed and compatible lubrication may need to be considered according to the application.

Vibration Resistance and Engineering Limitations

Stainless steel Keps nuts provide resistance to loosening through external-tooth washer engagement.

However, this mechanism is not equivalent to a prevailing-torque locking feature within the internal thread.

Important limitations include:

• Severe vibration.

• Repeated joint movement.

• Soft bearing surfaces.

• Delicate coatings.

• High mechanical loads.

• Critical structural joints.

• Repeated removal and installation.

For demanding applications, the fastening system must be evaluated through appropriate testing and engineering qualification.

Reuse and Maintenance

Some stainless steel Keps nuts may be reused when the washer remains intact and the application permits reuse.

However, repeated installation may deform the washer teeth or alter their engagement characteristics.

Before reuse, inspect:

• Washer retention.

• Tooth condition.

• Washer cracking.

• Thread damage.

• Corrosion.

• Nut deformation.

• Mating surface condition.

Reuse should not be assumed acceptable for critical or controlled assemblies without an approved maintenance procedure.

Stainless Steel Keps Nuts vs. Carbon Steel Keps Nuts

Material selection should be based on environmental exposure, mechanical requirements, manufacturing feasibility and total assembly cost.

Manufacturing Capabilities — Juxin Fasteners

Juxin Fasteners is an industrial fastener manufacturer specializing in standard and custom-engineered fastening components for global OEM manufacturers.

Our manufacturing capabilities include:

• Cold heading.

• Cold forming.

• CNC machining.

• Product-specific secondary manufacturing operations.

• Precision metal component manufacturing.

• Custom fastener manufacturing.

• Made-to-drawing production.

• Industrial batch manufacturing.

Stainless steel Keps nuts combine an internally threaded nut body, a captive external-tooth washer and a washer retention feature.

Depending on the approved design, manufacturing may involve forming operations, machining where required, internal threading, washer production and assembly processes.

The actual manufacturing route depends on material properties, product geometry, dimensional tolerances and production volume.

Not every product requires every available manufacturing process.

OEM Customization Options

Customer-specific requirements may include:

• Metric thread configurations.

• UNC and UNF thread requirements.

• AISI 304 or AISI 316 material specifications.

• Special stainless steel grades.

• Custom hex dimensions.

• Modified nut body heights.

• Washer outside diameter.

• Washer thickness.

• Washer tooth geometry.

• Washer material and hardness.

• Washer retention requirements.

• Surface finishing.

• Inspection specifications.

• OEM packaging.

All custom configurations require engineering and manufacturing feasibility review.

Quality Inspection and Functional Requirements

A project-specific inspection plan may include:

• Material grade verification.

• Thread gauge inspection.

• Hex dimension measurement.

• Nut body height inspection.

• Washer outside diameter measurement.

• Washer thickness inspection.

• Tooth geometry inspection.

• Washer retention inspection.

• Washer rotational freedom.

• Surface condition inspection.

• Functional assembly evaluation.

• Packaging and quantity verification.

Additional testing may be required for corrosion resistance, washer retention, mechanical performance or application-specific joint reliability.

Acceptance criteria must be defined by the customer specification.

Production Manager Considerations

Production managers should evaluate:

• Part feeding and orientation.

• Captive washer handling.

• Assembly cycle time.

• Installation tool compatibility.

• Thread galling risk.

• Washer seating.

• Surface marking.

• Joint reliability.

• Production consistency.

• Rework requirements.

• Total assembly cost.

The integrated washer may reduce component handling, but the final assembly process must be validated for the intended application.

OEM Procurement and Supply Chain Requirements

Purchasing managers and supplier development teams should establish:

• Approved engineering drawing.

• Drawing revision.

• Thread specification.

• Nut stainless steel grade.

• Washer material and hardness.

• Hex dimensions.

• Washer geometry.

• Surface finish.

• Corrosion requirements.

• Mechanical performance requirements.

• Inspection criteria.

• Sample approval requirements.

• Initial order quantity.

• Estimated annual demand.

• Packaging requirements.

• Production scheduling requirements.

For repeat OEM programs, consistent specifications and controlled product revisions support purchasing continuity and manufacturing reliability.

Relevant International Engineering Standards

ASME B1.1

Unified inch screw-thread requirements.

ASME B18.2.2

Dimensional requirements for applicable inch-series nuts.

ASME B18.21.1

Technical and dimensional requirements for applicable lock washers.

ISO 261 / ISO 724

ISO metric screw-thread designations and basic dimensions.

ISO 965 Series

ISO metric screw-thread tolerances.

ISO 3506-2

Mechanical properties of applicable corrosion-resistant stainless steel nuts.

ASTM A967 / ASTM A380

Relevant stainless steel passivation, cleaning and surface treatment references within their respective scopes.

Customer-Approved Engineering Drawings

The controlling specifications for nut dimensions, washer geometry, material grades, surface finishing and acceptance requirements.

These standards apply only within their respective technical scopes. References do not establish that every product configuration conforms to every listed standard or carries a certification.

Frequently Asked Questions

What is a stainless steel Keps nut?

It is a stainless steel hex nut combined with a captive external-tooth lock washer.

How does the locking washer work?

The washer teeth engage the mating bearing surface during tightening, providing resistance to relative rotation.

Are stainless steel Keps nuts suitable for severe vibration?

They should not be assumed suitable for severe vibration without application-specific testing and engineering qualification.

What is the difference between 18-8 and 316 stainless steel?

18-8 generally refers to chromium-nickel austenitic stainless steels commonly used in industrial fasteners. 

AISI 316 contains molybdenum and generally provides improved resistance in certain chloride-containing environments.

Is 304 stainless steel automatically A2-70?

No. The stainless steel material grade and finished fastener mechanical property designation must be verified separately.

Can stainless steel Keps nuts be used in marine equipment?

Selected configurations may be evaluated for marine-related equipment, but suitability depends on material grade, chloride exposure, crevice conditions and mechanical requirements.

Can these nuts be reused?

Reuse may be possible when the washer remains intact and the application permits it.

 The washer and threads must be inspected.

What metric sizes are supported?

The supplied product range includes M3, M4, M5, M6, M8, M10 and M12.

What American inch-thread sizes are supported?

The supplied range includes #4-40, #6-32, #8-32, 1/4-20, 5/16-18, 3/8-16 and 1/2-13.

Can UNF fine-thread configurations be manufactured?

Customer-specific UNF configurations may be evaluated through engineering and manufacturing feasibility review.

Can Juxin Fasteners manufacture custom stainless steel Keps nuts?

Yes. Juxin Fasteners supports OEM/ODM manufacturing, drawing-based engineering review and industrial batch production.

Request a Quote — Stainless Steel Keps Nuts and K-Lock Nuts

Juxin Fasteners manufactures industrial fastening components for global OEM manufacturers, 

Tier-1/Tier-2 suppliers, mechanical engineers, production managers, purchasing teams and industrial supply chain professionals.

We support stainless steel Keps nut manufacturing requirements for electrical enclosures, telecommunications equipment,

 industrial machinery, appliances, outdoor equipment and customer-specific mechanical assemblies.

Recommended RFQ Information

• 2D engineering drawing or 3D CAD model.

• Metric, UNC or UNF thread designation.

• Thread tolerance.

• Stainless steel nut material grade.

• Required mechanical property designation.

• Washer material and hardness.

• Hex dimensions.

• Nut body height and overall height.

• Washer outside diameter and thickness.

• Washer tooth geometry.

• Washer retention requirements.

• Surface finish.

• Mating bolt specification.

• Mating surface material.

• Corrosion exposure conditions.

• Installation torque requirements.

• Functional inspection requirements.

• Initial order quantity.

• Estimated annual purchasing volume.

• Packaging and delivery requirements.

Please send your engineering drawings and purchasing specifications for manufacturing feasibility review and quotation.

Juxin Fasteners

Industrial Fastener Manufacturer | Stainless Steel Keps Nuts | Custom K-Lock Nuts | OEM/ODM Fastener Manufacturing

Website: https://www.juxinfasteners.com/

Email: info@juxinfasteners.com

Packaging Standard

At Juxin Fasteners, we apply standardized export packaging to ensure product protection, traceability, and compliance with international logistics requirements.

1. Standard Export Packaging

Unless otherwise specified, all products will be packed according to our factory standard export packaging, which includes:

Moisture-resistant inner protection

Poly bag or small box packing as required

Reinforced export cartons

Clear labeling with part number, specification, batch number, and quantity

Palletizing for sea or air shipment when necessary

Our standard packaging is designed to ensure safe transportation, efficient warehousing, and long-distance international shipping.

2. Customized Packaging Options

We also provide customized packaging solutions according to customer requirements, including but not limited to:

Private labeling

Customized barcodes

Specific carton dimensions

Retail packaging

Special pallet configuration

Customer-specific marking and identification

So that you know, customized packaging may involve additional costs and extended lead time depending on the complexity of the requirements.

3. Compliance & Quality Assurance

All packaging processes are controlled under our ISO 9001 quality management system to ensure consistency, traceability, and product integrity throughout the supply chain.