DN Square Ball Screw Support Locknuts with Radial Set Screws

JX-DN Square Ball Screw Support Locknuts

Radial Set-Screw Locking and Copper Thread Protection for Precision Ball Screw Bearing Assemblies

Juxin Fasteners is an industrial fastener manufacturer providing standard and custom-engineered fastening components for global OEM manufacturers, 

machine tool builders, linear motion equipment manufacturers and industrial automation companies.

The JX-DN Square Ball Screw Support Locknut is a specialized precision locking component designed for securing bearings and related components on threaded ball screw shaft ends.

Unlike conventional square nuts used for general-purpose fastening, the JX-DN design combines a square external profile,

 fine-pitch internal threads and a radial set-screw locking mechanism with copper-alloy thread protection.

This construction is particularly relevant to fixed-end ball screw bearing supports, CNC feed-axis assemblies and precision motion-control equipment.

Juxin Fasteners supports CNC precision machining, OEM/ODM manufacturing, made-to-drawing metal components and industrial batch production.

Product Technical Specifications

Thread tolerances, surface finish, hardness, set-screw torque and locating-face runout must be confirmed from the approved JX-DN drawing.

What Is a Square Ball Screw Support Locknut?

A square ball screw support locknut is a specialized shaft-retaining nut used to secure bearings and other components on the threaded ends of ball screws.

The square external profile provides wrench engagement and distinguishes the product from conventional round precision bearing locknuts.

A locking mechanism prevents unintended nut rotation after the required axial position has been established.

Square support locknuts are commonly associated with precision ball screw fixed-end bearing arrangements.

How the JX-DN Radial Locking Mechanism Works

The JX-DN design uses radial locking screws installed through the outer body.

The screws act toward the mating shaft thread.

A copper-alloy protective insert is positioned between the locking screw and the shaft thread to help distribute contact pressure and reduce direct steel-to-steel thread damage.

A typical locking sequence is:

1. Thread the square locknut onto the correctly specified shaft end.

2. Position the nut against the designated bearing inner ring or spacer.

3. Establish the required axial position or bearing preload.

4. Tighten the radial locking screws according to the approved procedure.

5. Allow the protective inserts to engage the shaft threads.

6. Verify the final locked condition.

The set-screw tightening torque must be specified for the actual product size and design.

The locking mechanism must not be assumed to eliminate all axial backlash in the complete ball screw assembly.

Radial Set Screws and Copper Thread Protection

The copper-alloy protective interface is an important feature of this design.

Without a protective insert, a hardened steel set screw may produce concentrated contact pressure against the shaft thread.

A correctly designed protective insert helps reduce the risk of local thread damage.

Potential engineering benefits include:

• Reduced direct contact between steel locking screws and shaft threads.

• More controlled contact at the locking point.

• Improved suitability for adjustment and maintenance.

• Secure mechanical locking when correctly installed.

• Protection of precision shaft threads.

The actual protective insert material, hardness and geometry must be verified against the approved product specification.

The insert does not guarantee damage-free installation under incorrect tightening conditions.

Why Square Geometry Matters

The square profile is a defining feature of the JX-DN series.

Compared with a round locknut, the square body provides flat external surfaces for wrench engagement.

Potential advantages include:

• Convenient tool engagement.

• Suitability for certain ball screw support assemblies.

• Straightforward positioning during installation.

• Compact integration where the surrounding housing permits.

• Compatibility with customer-specific shaft-end designs.

The square nut must be selected according to the actual support-unit dimensions.

A square profile does not automatically make the nut interchangeable with every square-type bearing support locknut.

DIN C45 Medium-Carbon Steel

The specified JX-DN body material is DIN C45 medium-carbon steel.

C45 is a commonly used engineering steel for machined mechanical components.

Its properties depend on material condition, heat treatment, section size and the applicable material specification.

C45 is commonly identified as material number 1.0503 in European material references.

American Material Reference: AISI/SAE 1045

AISI/SAE 1045 is a commonly referenced American counterpart to European C45 steel.

Both belong to the medium-carbon steel family.

However, the two designations should not be treated as automatically identical in every chemical, mechanical or delivery requirement.

For an OEM project specifying AISI 1045, material acceptance should be based on the agreed standard and material certification.

C45 vs. 42CrMo Precision Locknuts

JX-DN uses C45 steel according to the supplied product specification.

Other precision locknut series may use chromium-molybdenum alloy steel such as 42CrMo.

These are different material families.

Material selection must follow the approved engineering drawing.

Precision Fine-Pitch Internal Threads

Ball screw shaft-end locknuts frequently use fine-pitch threads.

Fine-pitch threads can provide smaller axial advancement per revolution than coarser threads of the same nominal diameter.

This is useful when accurately positioning bearing components during assembly.

However, thread pitch alone does not determine bearing preload accuracy.

The final result also depends on:

• Shaft thread accuracy.

• Nut thread accuracy.

• Bearing arrangement.

• Locating-face geometry.

• Installation torque.

• Locking procedure.

Metric Thread Reference Sizes

The following sizes are industry reference examples relevant to square ball screw support locknuts.

These are metric fine-thread engineering references, not a confirmed JX-DN inventory or dimensional catalog.

The available JX-DN sizes, thread pitches and nut dimensions must be confirmed against the product drawing.

American Inch-Series Thread References

American machine builders may specify Unified inch-series threads for precision shaft assemblies.

Juxin Fasteners can evaluate custom inch-series square locknut designs according to customer drawings.

These Unified threads are engineering references for custom manufacturing evaluation.

They are not confirmed standard JX-DN sizes or stock products.

A custom inch-series square locknut requires review of the complete shaft thread, nut geometry, radial screw positions and locking insert design.

Metric and Inch Threads Are Not Interchangeable

Metric, UNC, UNF, BSW and BSF threads are separate systems.

For example:

• M8 × 1.0 is not interchangeable with 5/16-24 UNF.

• M10 × 1.0 is not interchangeable with 3/8-24 UNF.

• M12 × 1.0 is not interchangeable with 1/2-20 UNF.

• M20 × 1.0 is not interchangeable with 3/4-16 UNF.

Similar nominal diameters do not establish compatibility.

The correct thread system must match the mating shaft drawing.

Application 1: Ball Screw Fixed-End Support Units

Ball screw fixed-end supports commonly use bearing arrangements designed to locate the screw shaft axially.

A square locknut can be used to retain the bearing inner ring or associated spacer against the shaft shoulder.

Engineering requirements include:

• Correct shaft-end thread.

• Bearing inner-ring dimensions.

• Locknut outside dimensions.

• Axial clearance.

• Installation access.

• Locking screw position.

• Bearing preload.

The JX-DN is intended for these types of precision bearing-retention applications.

Application 2: CNC Machine Tool Feed Axes

CNC machine tools use ball screw drives to control axis movement.

Relevant applications include:

• CNC milling machine feed axes.

• Machining center linear axes.

• CNC lathe positioning systems.

• Precision grinding machine feed systems.

• Automated machine tool slides.

The JX-DN may be used to secure suitable ball screw support bearings.

The nut itself does not determine the positioning accuracy of the entire CNC axis.

Application 3: Industrial Linear Motion Systems

Industrial linear motion equipment frequently incorporates ball screws, support bearings and precision shaft-end components.

Potential applications include:

• Electric linear actuators.

• Precision positioning stages.

• Automated assembly machines.

• Industrial handling systems.

• Packaging machinery.

• Inspection and measuring equipment.

The locknut must match the support-unit design and operating requirements.

Application 4: Industrial Robotics

Robotic systems may use ball screw actuators or precision linear positioning mechanisms.

A square bearing locknut can be evaluated where the shaft-end design requires a compact retaining component with mechanical locking.

Application suitability depends on dynamic loading, vibration, installation clearance and maintenance requirements.

Application 5: Semiconductor Manufacturing Equipment

Semiconductor equipment may incorporate precision ball screw stages and mechanical positioning systems.

JX-DN square locknuts may be evaluated for mechanically suitable assemblies.

However, cleanroom, vacuum, contamination and material compatibility requirements must be assessed separately.

No semiconductor-specific qualification is implied.

Application 6: Laser Processing and Precision Cutting Equipment

Laser processing machines often rely on precision motion-control assemblies.

Potential JX-DN applications include ball screw bearing supports in suitable feed-axis systems.

Engineering considerations include:

• Repeated acceleration and deceleration.

• Axial positioning.

• Bearing retention.

• Shaft-end geometry.

• Vibration.

• Service access.

Application 7: Automated Material Handling

Industrial material handling systems may use ball screw actuators for controlled lifting or positioning.

Square locknuts can be evaluated for suitable support-bearing arrangements.

The load capacity of the complete assembly must be verified independently.

JX-DN vs. Standard Square Nuts

A JX-DN square precision locknut is not the same as a general-purpose square nut.

The JX-DN should not be marketed as a generic square nut for construction, furniture or ordinary structural fastening.

JX-DN vs. Round Precision Bearing Locknuts

Round precision locknuts may use radial locking, 30° flank locking or axial clamping.

The JX-DN is differentiated primarily by its square geometry and radial set-screw locking system with copper-alloy thread protection.

Actual dimensional interchangeability must be determined from engineering drawings.

Selecting the Correct Square Locknut

Before selecting a JX-DN square locknut, verify:

Thread Diameter and Pitch

The internal thread must match the mating shaft.

Nut Across-Flats Dimension

The square body must fit within the available support-unit clearance.

Nut Thickness

The axial thickness must be compatible with the bearing stack and threaded shaft length.

Radial Set-Screw Position

The locking screws must remain accessible after assembly.

Copper-Alloy Insert Design

The insert must provide the intended protective contact with the shaft thread.

Locating-Face Accuracy

The nut's locating face must satisfy the bearing assembly requirements.

Bearing Preload

The locknut must be installed according to the bearing manufacturer's specified procedure.

Assembly and Installation Guidelines

The following general process should be adapted to the approved JX-DN drawing and equipment manufacturer's instructions.

1. Confirm the shaft thread size and pitch.

2. Inspect the nut and shaft threads for damage.

3. Check the bearing and spacer locating surfaces.

4. Install the square nut using an appropriate wrench.

5. Establish the specified axial position or bearing preload.

6. Confirm that the protective inserts are correctly positioned.

7. Tighten the radial set screws to the approved torque.

8. Verify the final assembly and locking condition.

Do not tighten the set screws directly against the shaft thread if the design requires a copper-alloy protective insert.

Bearing Preload and Axial Positioning

The JX-DN locknut may be used to retain a bearing assembly at the intended axial position.

However, the bearing preload is determined by the complete bearing and shaft arrangement.

Relevant factors include:

• Bearing type.

• Shaft shoulder geometry.

• Spacer dimensions.

• Bearing internal clearance.

• Axial load.

• Thermal expansion.

• Assembly procedure.

The locknut should not be assigned a universal preload value.

Vibration Resistance and Locking Reliability

The radial set-screw locking mechanism provides mechanical resistance to unintended nut rotation.

Actual locking performance depends on:

• Set-screw tightening torque.

• Protective insert geometry.

• Shaft thread material.

• Thread engagement.

• Nut body material.

• Operating vibration.

• Maintenance condition.

Vibration resistance should be verified for the intended application.

No universal vibration rating or guaranteed elimination of loosening is implied.

Maintenance and Reuse

The JX-DN may be removed for bearing service or shaft assembly maintenance when the approved design permits.

Before reuse, inspect:

• Internal threads.

• Shaft threads.

• Radial locking screws.

• Copper-alloy inserts.

• Square body corners.

• Bearing locating face.

• Surface condition.

Replace damaged or worn locking components as required.

Common Engineering Problems and Solutions

Juxin Fasteners Manufacturing Capabilities

Juxin Fasteners is an industrial fastener manufacturer with manufacturing capabilities including:

• Cold heading.

• Cold forming.

• CNC machining.

• Product-specific secondary operations.

• Custom metal component manufacturing.

• OEM/ODM engineering support.

• Made-to-drawing fastener manufacturing.

• Industrial batch production.

For the JX-DN series, CNC precision machining is particularly relevant to the square geometry, internal threads, radial locking holes and bearing locating surfaces.

The manufacturing process is selected according to the actual product geometry, material specification, tolerance requirements and production volume.

Not every JX-DN product necessarily requires every manufacturing process available within the company's broader capabilities.

OEM/ODM Custom Square Locknut Manufacturing

Juxin Fasteners supports customer-specific square locknut projects based on approved 2D engineering drawings and 3D CAD models.

Potential customization includes:

• Custom square body dimensions.

• Special metric fine threads.

• Custom Unified inch-series threads.

• Reduced nut thickness.

• Special radial set-screw arrangements.

• Custom copper-alloy protective inserts.

• Customer-defined locating-face tolerances.

• Alternative material requirements.

• Surface finishing requirements.

• OEM part identification.

• Special inspection criteria.

• Batch packaging requirements.

All custom specifications are subject to engineering and manufacturing feasibility review.

Quality Inspection and Acceptance

A project-specific inspection plan may include:

• Material verification.

• Thread gauge inspection.

• Thread pitch verification.

• Across-flats dimension measurement.

• Nut thickness inspection.

• Radial set-screw hole inspection.

• Copper-alloy insert inspection.

• Locating-face dimensional inspection.

• Surface finish inspection.

• Functional locking verification.

Where required by the customer, locating-face runout and locking performance must be measured according to agreed inspection methods.

The applicable tolerances must be specified in the approved drawing.

Engineering Standards and References

ISO 261 and ISO 724

Relevant to ISO metric thread designations and basic dimensions.

ISO 965 Series

Relevant to ISO metric screw-thread tolerance requirements.

ASME B1.1

Relevant to Unified inch-series threads for customer-specific shaft designs.

EN ISO 683-1

Relevant to specified non-alloy engineering steel grades, including C45, subject to the applicable material and delivery requirements.

Customer Engineering Drawings

The approved JX-DN drawing must define the square body dimensions, internal thread, radial locking screw arrangement, protective inserts and functional tolerances.

Frequently Asked Questions

What is a JX-DN square locknut?

It is a precision square locknut designed for ball screw shaft-end bearing retention and related industrial motion-control applications.

What is the American name for this product?

Square Ball Screw Support Locknut and Square Bearing Locknut are relevant industry terms.

How does the locking mechanism work?

Radial set screws act through copper-alloy protective inserts to create locking resistance against the mating shaft threads.

Why is the body square?

The square profile provides wrench engagement and supports installation in compatible shaft assemblies.

What material is specified?

DIN C45 medium-carbon steel.

What is the American material reference?

AISI/SAE 1045 is a commonly referenced counterpart, subject to verification of the applicable material specification.

Does the locknut use nylon?

No nylon locking element is specified for the JX-DN design.

Is it a 30° flank-locking nut?

No. The JX-DN is described as a radial set-screw locking design with copper-alloy thread protection.

Can it be used for ball screw support bearings?

Yes, when the dimensions, shaft thread and bearing assembly requirements are compatible.

Can it eliminate all ball screw backlash?

No. Backlash and positioning accuracy depend on the complete ball screw, bearing, support and drive assembly.

Can Juxin Fasteners manufacture custom inch-thread versions?

Customer-specific Unified inch-series designs can be evaluated according to engineering drawings and manufacturing feasibility.

Can JX-DN locknuts be reused?

Reuse depends on the condition of the threads, protective inserts, locking screws and locating surfaces.

Request a Quote — JX-DN Square Ball Screw Support Locknut Manufacturer

Juxin Fasteners manufactures industrial fasteners and precision metal components for international OEM manufacturers, Tier-1 and Tier-2 suppliers, machine tool builders and industrial automation companies.

We support made-to-drawing square locknut projects for ball screw fixed-end support units, CNC feed-axis assemblies, precision linear actuators and custom shaft-retention systems.

Recommended RFQ Information

• 2D engineering drawing or 3D CAD model.

• JX-DN product model.

• Shaft thread diameter and pitch.

• Metric or Unified inch thread system.

• Internal thread tolerance.

• Square body across-flats dimensions.

• Nut axial thickness.

• Radial set-screw quantity and positions.

• Locking screw dimensions and specifications.

• Copper-alloy protective insert requirements.

• DIN C45 material specification.

• Surface treatment requirements.

• Locating-face accuracy requirements.

• Bearing arrangement and axial loading.

• Installation and locking torque requirements.

• Initial order quantity and annual purchasing forecast.

• Inspection and packaging requirements.

• Delivery requirements.

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

Juxin Fasteners

Industrial Fastener Manufacturer | OEM/ODM Fastener Manufacturing | CNC Precision Metal Components | Made-to-Drawing Industrial Fasteners

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.