Star-Type Tube-Connecting Nuts for Round Tubes

Star-Type Tube-Connecting Nuts for Round Metal and Plastic Tubes

Juxin Fasteners manufactures star-type tube-connecting nuts designed to create internal threaded fastening points inside compatible round metal and plastic tubes.

These specialized press-fit fasteners incorporate a central internally threaded steel component and a star-shaped spring-steel retaining element. 

The outward-facing retaining tabs engage the inside wall of the tube, providing mechanical retention without requiring a welded nut.

Also known as star-type threaded tube inserts, star-fanged tube nuts, threaded star-type tube ends and press-fit tube connector nuts, 

these components are used in tubular furniture manufacturing, equipment frames, retail display systems and other OEM assemblies.

Juxin Fasteners supports metric M6, M8 and M10 threads and Unified inch 1/4-20, 5/16-18 and 3/8-16 UNC configurations.

Custom tube-fit dimensions, retaining tab geometry and material specifications can be evaluated according to customer engineering drawings.

Product Design – Star-Shaped Spring Retaining Tabs

The defining feature of this product is its star-shaped retaining element.

Multiple flexible tabs extend outward from the central threaded body. During installation, the tabs deflect as the connector is pressed into the tube.

Once installed, the tabs engage the inner tube wall to resist movement and withdrawal.

Unlike a conventional cylindrical tube-connecting nut with retaining clips positioned along a long barrel, this star-type design uses a compact radial retaining arrangement.

Its main structural elements include:

• Central internally threaded steel component.

• Star-shaped spring-steel retaining element.

• Multiple outward-facing flexible tabs.

• Compact axial profile.

• Press-fit installation geometry.

• Zinc-plated steel surfaces.

• Metric or Unified inch internal threads.

The number of tabs, retaining diameter and overall height depend on the approved product configuration.

Key Product Features

Star-Shaped Retaining Geometry

The radial retaining tabs provide multiple contact points against the tube's internal surface.

This can help distribute engagement around the circumference of a compatible round tube.

Press-Fit Installation

The connector is pressed into the tube opening using a suitable installation tool or fixture.

Welding is not required for the intended installation method.

Internal Machine Thread

The central threaded component accepts a compatible machine screw, bolt or threaded stud.

Compact Design

The star-shaped structure provides an alternative to longer cylindrical tube connectors where installation depth and tube geometry are important.

Spring-Steel Retention

The retaining element is designed to deflect during insertion and engage the tube wall.

Zinc-Plated Steel Construction

Zinc plating provides corrosion protection for suitable indoor and moderately humid service environments.

Metric and Inch Thread Options

Both ISO metric and Unified inch threads are supported for international OEM manufacturing requirements.

Technical Specifications – Star-Type Tube-Connecting Nuts

Exact dimensions, material hardness, tube-fit requirements and mechanical performance must be confirmed against approved engineering drawings.

Metric Thread Specifications – M6, M8 and M10

M6 Star-Type Tube-Connecting Nuts

M6 configurations may be selected for compact tubular furniture, display fixtures and light equipment frames where the tube dimensions and required retention strength are appropriate.

M8 Star-Type Tube-Connecting Nuts

M8 configurations are relevant to larger tubular components and equipment supports requiring a medium-size internal threaded connection.

M10 Star-Type Tube-Connecting Nuts

M10 configurations can be evaluated for larger tubular structures with sufficient internal clearance and suitable wall strength.

The main thread diameter does not establish the connector's pull-out strength. Retention depends on the complete tube-and-insert assembly.

UNC Inch Thread Specifications for North American OEMs

1/4-20 UNC Star-Type Tube Nuts

Commonly relevant to North American tubular furniture, fixtures and equipment assemblies.

5/16-18 UNC Star-Type Tube Nuts

Suitable for evaluation in medium-size tubular structures requiring larger threaded connections.

3/8-16 UNC Star-Type Tube Nuts

Applicable to larger tube assemblies when the connector geometry and tube dimensions meet the required design criteria.

Custom UNF Thread Options

Juxin Fasteners can evaluate custom fine-thread configurations, including 1/4-28 UNF, 5/16-24 UNF and 3/8-24 UNF, according to customer drawings.

These are custom engineering options rather than confirmed standard configurations for the pictured product.

Metric and Inch Threads Are Not Interchangeable

Metric, UNC and UNF threads use different dimensions and thread pitches.

For example:

• M6 × 1.0 is not interchangeable with 1/4-20 UNC.

• M8 × 1.25 is not interchangeable with 5/16-18 UNC.

• M10 × 1.5 is not interchangeable with 3/8-16 UNC.

• 1/4-20 UNC is not interchangeable with 1/4-28 UNF.

All OEM drawings must specify the correct thread designation and tolerance.

Tube Diameter Selection – A Critical Engineering Requirement

Selecting a star-type tube-connecting nut requires matching the retaining element to the tube's internal dimensions.

Important parameters include:

• Tube outside diameter (OD).

• Tube inside diameter (ID).

• Tube wall thickness.

• Star retainer outside diameter.

• Retaining tab angle.

• Retaining tab thickness.

• Central threaded component dimensions.

• Overall installed height.

• Installation depth.

• Required insertion force.

• Required pull-out resistance.

A connector should never be selected solely by its internal thread size.

Common North American Tube Diameter References

These are common tube size references, not a confirmed compatibility chart for every Juxin Fasteners star-type insert.

For accurate selection, the actual tube inside diameter and wall thickness must be provided.

How Star-Type Tube-Connecting Nuts Work

The star-shaped retaining element uses elastic deformation and contact with the tube's inner wall.

During insertion, the tabs deflect to accommodate the tube opening.

Once installed, their geometry provides resistance against withdrawal and movement.

The resulting retention depends on the interference between the retaining tabs and the tube wall.

Important factors include:

• Retaining tab material and hardness.

• Tube material and hardness.

• Contact geometry.

• Installation direction.

• Tube dimensional tolerances.

• Surface finish.

• Axial loading.

• Applied tightening torque.

Star-shaped retaining tabs do not automatically guarantee a specified pull-out strength or vibration rating.

Installation Procedure for Round Tubing

Step 1 – Verify Tube Dimensions

Confirm the tube inside diameter, outside diameter and wall thickness.

Step 2 – Inspect the Tube Opening

Remove burrs and inspect the tube end for deformation or damage.

Step 3 – Position the Star-Type Insert

Align the central threaded component with the tube axis.

Step 4 – Apply Controlled Installation Force

Use an appropriate press or installation fixture to insert the connector.

Avoid uncontrolled impact that could damage the threaded component or retaining tabs.

Step 5 – Verify Installation Depth

Confirm that the insert is positioned according to the approved assembly drawing.

Step 6 – Install the Mating Fastener

Engage the specified machine screw or threaded stud and apply the validated tightening torque.

Carbon Steel and 65Mn Spring-Steel Construction

The product uses different materials for the threaded and retaining functions.

Carbon Steel Threaded Component

The carbon steel component provides the internal machine thread and supports the mating fastener.

Its mechanical performance depends on the steel grade, thread geometry and manufacturing process.

65Mn Spring-Steel Retaining Element

65Mn is a manganese spring steel suitable for components requiring elastic deformation after appropriate processing and heat treatment.

For star-type tube connectors, the spring element must maintain sufficient elasticity and contact force during installation.

Important production parameters include:

• Material thickness.

• Tab forming accuracy.

• Heat treatment.

• Hardness.

• Elastic recovery.

• Surface protection.

• Dimensional consistency.

The exact hardness and heat-treatment requirements must be confirmed by the approved product specification.

Zinc-Plated Surface Finish

Zinc plating is commonly used to protect steel fasteners from corrosion.

For tube-connecting nuts, zinc plating may provide suitable protection in indoor environments and applications involving occasional humidity.

Corrosion performance depends on coating thickness, passivation, exposure conditions and installation damage.

For specified corrosion testing, ASTM B117 may be used when required by the customer.

No universal salt spray performance should be claimed without supporting test results.

Star-Type Tube Nuts vs. Cylindrical Tube-Connecting Nuts

Both designs provide internal threaded connections inside compatible tubing, but their retaining structures differ.

Neither design should automatically be considered stronger without comparative testing under the same tube and loading conditions.

Star-Type Tube Nuts vs. T-Slot Nuts

Star-type tube-connecting nuts are not the same as T-slot nuts used in aluminum extrusion framing.

A star-type tube nut is pressed inside a compatible hollow tube.

A T-slot nut engages a defined slot in an aluminum extrusion or machine-tool table.

Some T-slot nut designs can be inserted into an assembled extrusion and rotated into position.

That installation method does not apply to the pictured star-type tube-connecting nut.

Industrial Applications – Tubular Furniture Manufacturing

Star-type tube-connecting nuts can provide internal threaded connections for suitable tubular furniture components.

Potential applications include:

• Office furniture frames.

• Tubular table legs.

• Metal chair components.

• Adjustable furniture accessories.

• Commercial furniture supports.

• Modular furniture assemblies.

• Shelving and display furniture.

For furniture OEMs, the connector must be selected according to the tube dimensions, joint loading and expected assembly cycles.

Height-Adjustable Office Furniture

Tubular components are used in adjustable desks and office equipment.

Star-type threaded inserts may be considered for suitable auxiliary mounting connections, adjustable components and noncritical attachments.

Load-bearing lifting mechanisms require specific engineering validation.

Fitness and Recreational Equipment

Potential applications include:

• Tubular equipment accessories.

• Removable frame attachments.

• Equipment stands.

• Adjustment hardware.

• Noncritical support components.

Connections subjected to high dynamic loads or user safety requirements must be validated before use.

Retail Display Stands and Exhibition Equipment

Retail displays frequently use round metal tubing for modular structures.

Potential applications include:

• Product display stands.

• Exhibition frames.

• Retail fixtures.

• Promotional display structures.

• Removable tubular supports.

A press-fit threaded connector can reduce the need for welded threaded attachment points in suitable designs.

Industrial Automation and Equipment Frames

Round tubular components are used in industrial workstations, equipment supports and machinery accessories.

Star-type tube-connecting nuts may be considered for:

• Equipment stands.

• Tubular machine accessories.

• Light-duty support frames.

• Removable brackets.

• Industrial display fixtures.

• Assembly workstation accessories.

These applications must be distinguished from T-slot aluminum extrusion fastening systems.

Warehouse and Logistics Equipment

Tubular structures are used in selected warehouse fixtures, carts and material-handling accessories.

Potential applications include removable tubular components and noncritical threaded attachments.

The complete joint must be evaluated for vibration, impact and service loading.

Automotive and Transportation Equipment

Star-type threaded tube inserts may be evaluated for selected tubular automotive accessories and transportation equipment components.

Potential applications include noncritical tubular brackets, equipment supports and removable attachments.

Their use in dashboards, bumpers or other automotive systems cannot be assumed without application-specific drawings and validation.

Electric Vehicle and Energy Equipment

Custom tubular equipment frames and auxiliary structures may require compact internal threaded connections.

Star-type inserts may be considered where the tube dimensions, environmental conditions and required mechanical performance are suitable.

They should not be represented as qualified for high-voltage, battery safety or structural crash applications without appropriate testing and approval.

Engineering Considerations for Design Engineers

Axial Pull-Out Resistance

The retaining tabs must provide sufficient resistance against the expected axial loads.

Rotational Resistance

The connector must resist rotation when the mating bolt is tightened.

Tube Wall Deformation

Excessive interference may damage thin-walled tubing.

Retaining Tab Elasticity

Spring properties must remain suitable after manufacturing and installation.

Thread Engagement

The central threaded component must provide adequate engagement with the mating bolt or stud.

Installation Depth

The connector must be positioned correctly to maintain the intended assembly geometry.

Vibration Resistance

Vibration performance must be verified for the complete joint.

Repeated Assembly

The threaded connection and installed connector should be evaluated for the expected number of assembly and removal cycles.

Environmental Conditions

Temperature, humidity, corrosion and material aging may affect long-term performance.

Recommended OEM Validation Tests

Depending on the application, testing may include:

• Installation force.

• Axial pull-out resistance.

• Rotational resistance.

• Internal thread stripping resistance.

• Bolt tightening torque.

• Retaining tab deformation.

• Tube wall deformation.

• Vibration performance.

• Fatigue resistance.

• Corrosion testing.

• Repeated assembly and removal.

Testing should use actual production tubing and the approved connector configuration.

Custom Manufacturing by Juxin Fasteners

Juxin Fasteners is an industrial fastener manufacturer supporting OEM and ODM production of specialized metal fastening components.

Our manufacturing capabilities include cold heading, cold forming, CNC machining and secondary metalworking processes.

For star-type tube-connecting nuts, manufacturing may involve:

• Steel threaded component production.

• Internal threading.

• Spring-steel stamping and forming.

• Retaining tab geometry control.

• Heat treatment where specified.

• Component assembly.

• Zinc plating.

• Dimensional inspection.

• Functional fit testing.

The manufacturing process is selected according to the approved product geometry, materials, tolerances and production quantities.

Custom Engineering Options

Juxin Fasteners can evaluate:

• Metric M6, M8 and M10 threads.

• UNC inch threads.

• Custom UNF threads.

• Star retainer outside diameter.

• Retaining tab count.

• Retaining tab geometry.

• Spring-steel thickness.

• Spring material and hardness.

• Threaded component height.

• Installation depth.

• Tube-fit dimensions.

• Zinc-plating requirements.

• Custom packaging.

• OEM identification and inspection requirements.

All configurations are subject to engineering and manufacturing feasibility review.

Quality Control for OEM Batch Production

Inspection requirements may include:

• Internal thread GO/NO-GO gauge inspection.

• Threaded component dimensions.

• Star retainer outside diameter.

• Retaining tab thickness.

• Retaining tab angle.

• Retaining tab count.

• Material verification.

• Hardness inspection where specified.

• Surface finish inspection.

• Coating thickness where specified.

• Installation fit verification.

• Pull-out testing when required.

• Rotational resistance testing when required.

• Batch identification and drawing revision control.

For Unified inch threads, ASME B1.1 provides a relevant thread specification reference.

Final inspection criteria must follow the approved OEM drawing.

Production Efficiency and Assembly Engineering

For manufacturing engineers and production managers, a properly selected press-fit tube connector may simplify threaded attachment within hollow tubular structures.

Potential production considerations include:

• Reduced welding operations.

• Repeatable installation depth.

• Consistent tube dimensions.

• Controlled insertion force.

• Efficient assembly fixtures.

• Reduced secondary machining.

• Stable thread alignment.

• Repeatable batch quality.

• Controlled inspection procedures.

Actual production savings depend on the application, installation method and manufacturing volume.

OEM Procurement and International Manufacturing Support

Juxin Fasteners supports B2B manufacturers requiring customized star-type tube-connecting nuts and threaded tube components.

Our technical and purchasing support is intended for:

• Design engineers.

• Mechanical and structural engineers.

• Manufacturing engineers.

• Production managers.

• Procurement development specialists.

• Purchasing specialists.

• Procurement managers.

• Supply chain managers.

We support international OEM manufacturing programs in North America, South America, Europe and other industrial markets.

For procurement evaluation, customers should provide the required thread size, tube dimensions, material specifications, finish, estimated annual demand and mechanical performance requirements.

Frequently Asked Questions

What are star-type tube-connecting nuts?

They are internally threaded tube fasteners incorporating star-shaped spring retaining tabs that engage the inner wall of compatible tubing.

Are star-type tube nuts the same as star-fangled nuts?

Star-fangled nuts is a related industry term for certain star-shaped threaded tube inserts. Exact geometry and compatibility vary between designs.

What is the difference between a star-type tube nut and a cylindrical tube nut?

A star-type design uses a compact radial retaining element, while a cylindrical design uses retaining clips positioned along a longer body.

Do star-type tube nuts require welding?

No. The intended installation method is press fitting into compatible tubing.

Can star-type tube nuts be used in plastic tubes?

They may be suitable for selected plastic tubes when the material, dimensions and retention performance have been verified.

Are M6, M8 and M10 available?

These metric thread sizes are included in the product specification. The matching tube-fit dimensions must be confirmed.

Are 1/4-20, 5/16-18 and 3/8-16 available?

These Unified coarse thread configurations are included in the product specification, subject to the required tube-fit design.

Can star-type tube nuts be used in aluminum extrusion T-slots?

This product is designed for installation inside compatible hollow tubing, not for conventional T-slot engagement.

Can Juxin Fasteners manufacture custom star-type inserts?

Yes. Juxin Fasteners can evaluate drawing-based requirements for thread sizes, retaining tab geometry, tube dimensions, materials and surface finishes.

What determines the pull-out strength?

Pull-out resistance depends on the retaining element geometry, tube material, internal diameter, interference and installation conditions.

Are metric and UNC threads interchangeable?

No. Metric and Unified inch threads use different dimensions and pitches.

What information is needed for an OEM quotation?

Please provide the tube inside diameter, outside diameter, wall thickness, thread size, connector drawing, material requirements, expected mechanical performance and estimated annual purchasing quantity.

Request an OEM Manufacturing Quote – Star-Type Tube-Connecting Nuts

Juxin Fasteners manufactures star-type tube-connecting nuts for threaded connections inside round metal and suitable plastic tubing.

Our manufacturing services support drawing-based OEM and ODM production, spring-steel retaining components, precision internal threading, zinc-plated finishes, dimensional inspection and repeat-order batch manufacturing.

For technical evaluation and quotation, please provide your 2D/3D engineering drawings, tube dimensions, thread specifications, material requirements and estimated annual purchasing quantity.

Manufacturer: Juxin Fasteners

Product: Star-Type Tube-Connecting Nuts for Round Tubes

Materials: Carbon Steel + 65Mn Spring Steel

Metric Threads: M6, M8, M10

Inch Threads: 1/4-20, 5/16-18, 3/8-16 UNC

Installation: Internal Press Fit

Retaining Design: Star-Shaped Spring Tabs

Surface Finish: Zinc Plating

Manufacturing: OEM / ODM, Custom Metal Forming, Threading and Batch Production

Email: info@juxinfasteners.com

Website: www.juxinfasteners.com

Send your 2D/3D drawings, tube dimensions, thread specifications and estimated annual demand to request a custom star-type tube-connecting nut manufacturing quotation from Juxin Fasteners.

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.