Serrated Hex Flange Lock Nuts | Radial Serrated Flange Nuts

Serrated Hex Flange Lock Nuts for Industrial OEM Assemblies

Radial Serrated Flange Nuts — Steel and Stainless Steel Manufacturing

Juxin Fasteners manufactures serrated hex flange lock nuts for industrial machinery, automotive equipment, electrical enclosures, production equipment and custom OEM fastening assemblies.

These hexagonal nuts incorporate an integral circular flange with radial serrations on the bearing surface. 

During tightening, the serrations engage the mating component and provide additional resistance to relative rotation.

The integrated flange offers a wider bearing area than a conventional hex nut, often eliminating the need for a separate plain washer where the joint design permits.

Unlike nylon-insert or distorted-thread locknuts, serrated flange nuts rely primarily on the interaction between their serrated bearing surface and the clamped material to resist loosening.

Juxin Fasteners supports standard and custom-engineered fastening components through cold heading, cold forming, CNC machining and appropriate secondary manufacturing operations. 

The process route for each product is selected according to its design and manufacturing requirements.

Product Specifications

All dimensions, tolerances, material grades, mechanical properties and finishes must be confirmed against the approved engineering drawing.

What Is a Serrated Hex Flange Nut?

A serrated hex flange nut is a hexagonal internally threaded fastener with an integral flange and serrations on its bearing face.

The flange distributes the applied clamping force over a larger contact area than a conventional hex nut without a washer.

The serrations are designed to engage the mating surface and increase resistance to nut rotation.

This configuration is commonly used in machinery and equipment where an integrated bearing surface and moderate resistance to loosening are desirable.

The effectiveness of the serrations depends on the material, surface hardness, coating, tightening conditions and operating loads.

How Radial Flange Serrations Work

1. Contact with the Mating Surface

During installation, the serrated underside of the flange contacts the clamped component.

2. Local Surface Engagement

As tightening progresses, the serrations may penetrate or mechanically engage the mating surface.

The degree of engagement depends on the material and surface condition.

3. Resistance to Rotation

The serrated contact interface provides additional resistance to relative rotation between the nut and the clamped component.

4. Joint Retention

The resulting connection may resist loosening under suitable operating conditions.

However, the serrations do not create prevailing torque within the internal thread.

For demanding vibration applications, the complete joint must be validated.

Key Engineering Features

Integral Flange Design

The integral flange provides a wider bearing surface.

Potential advantages include:

• Reduced need for a separate plain washer

• Larger contact area

• Simplified component handling

• Fewer loose assembly components

• Potential assembly-process efficiency improvements

A larger flange does not automatically guarantee lower contact stress at every point because the serrations create localized contact.

Radial Serrated Bearing Face

The radial teeth are designed to engage the mating material.

Important parameters include:

• Serration quantity

• Tooth height

• Tooth angle

• Tooth pitch

• Serrated contact diameter

• Flange thickness

• Material hardness

• Surface coating

These features influence how the nut interacts with the mating surface.

Hexagonal Wrenching Surface

The hexagonal body allows installation with a suitable wrench or socket.

Wrench size and nut height must match the specified dimensions.

One-Piece Nut Geometry

The hexagonal body and flange form an integral component.

This avoids the need to position a separate plain washer during suitable assembly operations.

Metric Thread Specifications

The currently identified product sizes are M6 and M8.

The values above are standard metric coarse-thread references.

Actual thread pitch and tolerance must be verified from the approved drawing.

Custom Unified Inch-Thread Options

For North American OEM projects, custom serrated flange nuts with Unified inch threads may be evaluated.

These are standard Unified thread references for potential custom designs, not confirmed inventory items.

Manufacturing feasibility depends on the thread size, flange geometry, material and production requirements.

Metric and Unified threads are not directly interchangeable.

Material Options

ML08AL Steel

ML08AL is an identified material option for this product.

The material grade must be evaluated according to the required forming characteristics, mechanical properties and finished-part specification.

ML08AL should not be equated automatically with SAE Grade 8 or ISO property class 8.

A finished nut's mechanical property class must be established through its applicable specification and verification requirements.

Stainless Steel

Stainless steel versions may be considered for equipment requiring corrosion resistance.

Potential grades such as 304 and 316 should be evaluated according to the customer's engineering requirements.

The exact stainless steel grade must be specified.

The serration geometry and hardness relationship between the nut and mating surface are particularly important.

Serrations may behave differently against hard stainless steel, hardened steel or coated surfaces than against softer carbon steel.

Surface Treatment Options

Carbon steel serrated flange nuts may receive protective surface treatments according to customer requirements.

Potential options include:

• Zinc plating

• Zinc alloy plating

• Zinc flake coating

• Black oxide

• Phosphate coating

• Other approved industrial finishes

The photographed product has a yellow metallic appearance.

Its precise plating system, coating thickness and corrosion performance must be confirmed before publication as product specifications.

For stainless steel versions, a natural finish or specified surface treatment may be evaluated.

Serrated Flange Nuts vs. Smooth Flange Nuts

Both products incorporate an integral flange, but their bearing surfaces differ.

The choice depends on the joint design and acceptable surface condition.

Serrated Flange Nuts vs. Nylon-Insert Flange Locknuts

A nylon-insert flange locknut uses a polymer element to create friction against the mating thread.

A serrated flange nut uses the contact between its serrated bearing face and the clamped component.

These are different locking mechanisms.

Nylon-insert designs may be preferable where a prevailing-torque mechanism is required and suitable for the operating temperature.

Serrated flange designs may be considered where the mating surface permits tooth engagement.

Serrated Flange Nuts vs. Distorted-Thread Flange Locknuts

Distorted-thread flange locknuts create prevailing torque through controlled deformation of the nut thread or body.

Serrated flange nuts do not inherently generate that same prevailing torque.

For vibration-sensitive connections, engineers should determine whether surface engagement, prevailing torque or another locking method is appropriate.

Engineering Considerations for Surface Contact

The mating material is an important selection factor.

Carbon Steel Components

Serrations may engage suitable steel surfaces, depending on hardness, coating and joint conditions.

Aluminum Components

Aluminum is often softer than steel.

Serrations may produce more pronounced surface indentation.

Engineers should evaluate the effect on surface damage, joint settlement and long-term preload.

Stainless Steel Components

Hardness and surface condition influence serration engagement.

The use of stainless steel serrated nuts does not automatically guarantee effective locking against every stainless steel surface.

Painted or Coated Components

Serrations may damage or penetrate protective coatings.

This can affect corrosion protection and appearance.

The assembly must be evaluated where coating integrity is important.

Composite or Plastic Components

Serrated steel flange nuts may damage relatively soft materials.

These applications require careful assessment and may benefit from an alternative bearing surface or fastening design.

Vibration Resistance and Limitations

Serrated flange nuts are often selected for equipment experiencing mild vibration.

However, their locking effectiveness depends on the complete bolted joint.

Important factors include:

• Bolt preload

• Mating surface hardness

• Serration geometry

• Surface coatings

• Joint stiffness

• Transverse loading

• Vibration amplitude

• Thermal cycling

• Surface settlement

The serrations cannot compensate for inadequate preload or an unsuitable joint design.

For critical connections, application-specific vibration and loosening tests may be necessary.

Automotive and EV Manufacturing Applications

Serrated flange nuts may be considered for selected automotive and electric vehicle equipment assemblies.

Potential applications include:

• Noncritical mounting brackets

• Vehicle accessory assemblies

• Equipment supports

• Production tooling

• Assembly fixtures

• Selected metal-to-metal connections

The appropriate nut design depends on the mating materials, load requirements and assembly specifications.

Safety-critical applications require the relevant OEM qualification and validation.

Industrial Machinery Applications

Industrial machinery often includes bolted connections exposed to repeated operation and moderate vibration.

Potential applications include:

• Equipment mounting brackets

• Machinery covers

• Mechanical frames

• Motor accessories

• Auxiliary supports

• Industrial fixtures

Production engineers should evaluate tightening methods, mating surface conditions and inspection requirements.

Electrical Enclosures and Control Cabinets

Serrated flange nuts may be used in selected electrical enclosure and control cabinet assemblies.

Potential applications include:

• Steel enclosure brackets

• Mounting panels

• Mechanical supports

• Equipment accessories

• Cabinet hardware

Where electrical bonding or grounding is required, the entire connection must be designed and tested for that purpose.

Serrations alone do not establish an approved grounding connection.

HVAC and Building Equipment

Heating, ventilation and air-conditioning equipment may use serrated flange nuts in suitable sheet metal and structural accessory assemblies.

Potential applications include:

• Equipment frames

• Fan housing brackets

• Duct support accessories

• Mechanical mounting components

• Serviceable equipment connections

The selected nut must match the required load and operating environment.

Industrial Automation and Robotics

Automation equipment may require reliable fastening of brackets, guards and mechanical accessories.

Serrated flange nuts may reduce the need for separate washers in appropriate assemblies.

Manufacturing engineers should evaluate:

• Assembly access

• Tool compatibility

• Torque requirements

• Surface condition

• Component handling

• Rework procedures

Energy Storage and Power Electronics Equipment

Energy storage systems and power electronics equipment may include mechanical supports and enclosure assemblies.

Serrated flange nuts may be considered for appropriate noncritical mechanical connections.

The design must account for vibration, thermal exposure, corrosion and any electrical requirements.

Data Center and Server Infrastructure

Data center infrastructure includes electrical cabinets, mechanical equipment and auxiliary support assemblies.

Serrated flange nuts may be evaluated for suitable metal-to-metal mechanical connections.

Their use should be based on actual engineering requirements rather than an assumption that all server equipment requires vibration-resistant nuts.

Rail Transit and Transportation Equipment

Transportation equipment may contain mechanical assemblies exposed to vibration.

Serrated flange nuts can be considered where permitted by the applicable design specification.

Rail applications require appropriate engineering approval and verification.

No rail-industry certification is implied.

Manufacturing Capabilities

Juxin Fasteners is an industrial fastener manufacturer supporting standard and custom-engineered fastening components.

Our manufacturing capabilities include:

• Cold heading

• Cold forming

• CNC machining

• Product-specific secondary operations

• Thread manufacturing

• Surface finishing according to specification

• Dimensional inspection

Depending on the product geometry, a flange nut may be formed using suitable cold forming processes, with additional operations where required.

The actual manufacturing sequence must be established through engineering review.

OEM/ODM Customization

Juxin Fasteners supports made-to-drawing manufacturing based on customer engineering specifications.

Customization may include:

• Thread diameter

• Thread pitch

• UNC or UNF thread form

• Hexagon dimensions

• Flange diameter

• Flange thickness

• Serration pitch and geometry

• Nut height

• Material grade

• Mechanical property requirements

• Surface treatment

• Dimensional tolerances

• Customer part identification

• Packaging requirements

Manufacturing feasibility is reviewed according to product geometry, material and production volume.

Production and Assembly Efficiency

For production managers, serrated flange nuts may provide opportunities to simplify suitable fastening operations.

An integrated flange can reduce the number of separate components handled during assembly.

However, total manufacturing cost should consider more than the unit price of the nut.

Relevant factors include:

• Fastener unit cost

• Assembly time

• Tooling compatibility

• Installation torque

• Surface damage risk

• Inspection requirements

• Rework frequency

• Corrosion protection

• Production volume

A design that reduces component count may still require additional validation or process controls.

Quality Inspection and Engineering Validation

Depending on the approved drawing, inspection may include:

• Material verification

• Internal thread gauging

• Hexagon dimensions

• Overall nut height

• Flange diameter

• Flange thickness

• Serration geometry

• Surface finish

• Coating thickness

• Mechanical property testing where specified

• Functional assembly testing

For applications requiring vibration resistance, the customer should define the appropriate test conditions and acceptance criteria.

Relevant International Standards

The following standards may provide engineering references for applicable serrated flange nut designs.

The applicability of each standard must be verified for the actual nut geometry, thread and material.

DIN 6923 and ISO 4161 should not be used as automatic certification claims for every custom serrated flange nut.

Frequently Asked Questions

What is a serrated hex flange nut?

It is a hexagonal nut with an integral flange featuring serrations on the bearing surface.

How does a serrated flange nut resist loosening?

The serrations engage the mating material and create additional resistance to relative rotation.

Is a serrated flange nut a prevailing-torque locknut?

Not inherently. Its primary locking action occurs at the bearing surface rather than through controlled interference with the mating bolt thread.

Can serrated flange nuts replace washers?

The integral flange can eliminate the need for a separate plain washer in suitable designs, but the complete joint must be evaluated.

Can serrations damage painted surfaces?

Yes. Serrations may penetrate or damage paint and other protective coatings.

Are serrated flange nuts suitable for aluminum?

They may be used in appropriately engineered assemblies, but surface indentation and joint settlement must be evaluated.

What sizes are identified for this product?

M6 and M8 are the currently identified metric sizes.

Can Juxin Fasteners manufacture UNC and UNF versions?

Custom Unified inch-thread designs can be evaluated according to engineering drawings.

Are metric and inch threads interchangeable?

No. Their thread dimensions and pitch must match the mating fastener.

What is ML08AL?

ML08AL is an identified steel material grade. It should not be confused with a finished nut mechanical property class.

What surface finish is shown in the photograph?

The photograph shows a yellow metallic finish. The exact plating specification must be confirmed.

Can Juxin Fasteners manufacture custom serration geometry?

Customer-specific designs can be evaluated according to manufacturing feasibility and functional requirements.

Are serrated flange nuts suitable for severe vibration?

Suitability depends on the complete bolted joint. Severe vibration applications require appropriate engineering validation.

Can Juxin Fasteners manufacture according to OEM drawings?

Yes. Juxin Fasteners supports OEM/ODM made-to-drawing industrial fastener manufacturing.

Request a Quote — Serrated Hex Flange Lock Nuts

Juxin Fasteners manufactures standard and custom-engineered industrial fastening components for global OEM, Tier-1 and Tier-2 manufacturing programs.

Our manufacturing capabilities combine cold heading, cold forming, CNC machining and product-specific secondary operations according to engineering and production requirements.

We support drawing-based manufacturing of serrated flange nuts, custom locking nuts and precision metal fastening components.

Recommended RFQ Information

• 2D engineering drawing or 3D CAD model

• Customer part number

• Thread size and pitch

• Metric, UNC or UNF designation

• Material grade

• Required mechanical property class

• Hexagon width across flats

• Overall height

• Flange diameter and thickness

• Serration geometry

• Surface treatment

• Coating thickness

• Mating component material

• Mating surface condition

• Required tightening conditions

• Vibration or functional testing requirements

• Inspection and acceptance criteria

• Initial order quantity

• Estimated annual demand

• Packaging requirements

• Target delivery schedule

Please send your drawings, samples or technical specifications for manufacturing feasibility review and quotation.

Juxin Fasteners

Industrial Fastener Manufacturer | Serrated Hex Flange Nuts | Custom OEM Locknut 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.