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OEM & Wholesale Linear Shaft Supply Service

Home · Products · Linear Shaft

Linear Shaft

Linear optical axes, as fundamental and crucial linear motion components, are primarily classified based on their core structural features and dimensional standards to meet the diverse needs of different applications regarding rigidity, weight, cost, compatibility, and installation methods.

The core classifications are as follows:

By Core Structure

Solid Linear Optical Axles: Such as the HS/SF series (metric) and SI series (imperial). Made from solid round steel through precision machining and hardening, they possess excellent rigidity and load-bearing capacity, with a robust structure. They are the most widely used and versatile standard optical axes.

Hollow Linear Optical Axles: Also known as the SP series. Manufactured using hollow tubing, their core feature is lightweight design. While ensuring sufficient rigidity, they significantly reduce the weight of moving parts and provide space for internal cabling, air pipes, or the installation of other components. They are suitable for weight-sensitive or integrated wiring applications such as automation equipment and robotics.

By Dimensional Standards

Metric Standard Optical Axles: Such as the HS/SF series (solid) and SP series (hollow). Its key dimensions, such as diameter and tolerances, adopt the internationally recognized metric (millimeters) standard, which is currently the mainstream choice in the domestic market, facilitating compatibility with most domestic and international mainstream brand linear bearings, supports, and other accessories.

Imperial Standard Optical Shafts: Also known as SI series (solid). Their key dimensions, such as diameter, adopt the imperial (inch) standard, primarily serving applications requiring direct replacement and compatibility with specific imported European and American equipment, existing designs, or special components.

The selection of linear optical shafts first requires a trade-off between the high rigidity of solid shafts and the lightweight of hollow shafts, and then specification matching based on the design standard system (metric/imperial) of the equipment to ensure optimal performance adaptation and installation compatibility.

About
Lishui Wangong Precision Machinery Co., Ltd.
Lishui Wangong Precision Machinery Co., Ltd. was founded in 2008 and is located in Lishui City, Zhejiang Province. We take pride in our state-of-the-art R&D and production facility, covering an impressive 52,000 square meters. Our expertise lies in manufacturing precision transmission components, such as ball screw assemblies, linear guides, roller guides, linear shafts, and high precision linear shaft.

As a china linear shaft manufacturer, we seamlessly integrate research and development, production, sales, and service. We have successfully incorporated advanced equipment and cutting-edge technologies from renowned countries like Germany, Japan, and Taiwan. Our commitment to innovation has led to the acquisition of multiple product design patents, and we proudly adhere to ISO9001 certification standards.
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What Is a Linear Shaft?

A linear shaft, also known as a linear motion shaft, guide shaft, precision shaft, linear optical shaft, or linear guide shaft, is a cylindrical precision component used in linear motion systems. Its main function is to provide accurate guidance, stable support, and reliable positioning for moving parts.

In automation equipment, CNC machines, packaging machinery, 3D printers, robotic systems, inspection devices, and precision transmission mechanisms, a linear shaft is commonly used together with linear bearings, shaft supports, sliding blocks, support rails, and other linear motion components. This combination allows mechanical parts to move smoothly and consistently along a straight path.

A linear shaft usually does not generate motion by itself. Instead, it acts as a guiding and supporting element. The actual driving force typically comes from:

Drive Systems

01
Ball screws
02
Lead screws
03
Timing belts
04
Pneumatic cylinders
05
Electric actuators
06
Rack and pinion systems
07
Linear motors

How Does a Linear Shaft Work?

The working principle of a linear shaft is straightforward, but its role in a mechanical system is essential. It provides a precision guiding surface that allows a linear bearing, sliding block, or motion assembly to travel along a fixed straight path.

At Wangong, the performance of a linear shaft begins long before it is installed in a machine. Through controlled material selection, precision machining, heat treatment, surface finishing, and full-process inspection, each shaft is designed to support stable and predictable motion in real working conditions.

Basic Working Process

In a typical linear motion system, the linear shaft is fixed to a machine frame, shaft support, or support rail. A linear bearing or sliding block is mounted on the moving component. When the drive system starts, the moving component travels along the linear shaft.

The basic motion process is:

01
The linear shaft is fixed to the machine base
02
The linear bearing or sliding block is mounted on the shaft
03
The drive system pushes or pulls the moving component
04
The bearing moves along the shaft surface
05
The moving part completes linear movement along the designed path

In a ball-type linear bearing system, steel balls circulate inside the bearing and roll along the surface of the linear shaft. This rolling contact reduces friction and helps achieve smooth, low-resistance linear movement.

Main Features of Wangong Linear Shafts

Linear shafts are widely used in automation and mechanical systems because they are precise, durable, easy to install, and cost-effective. Wangong linear shafts are manufactured with attention to the details that affect real motion performance.

01
01

High Straightness

Good straightness allows the linear bearing or slider to move smoothly along the shaft. Poor straightness may cause jamming, vibration, uneven wear, or positioning error. Wangong controls straightness through precision machining, grinding, and inspection processes.

02
02

High Surface Hardness

Many linear shafts are treated by induction hardening, chrome plating, or other surface strengthening processes. Higher surface hardness improves wear resistance and extends service life, especially in high-frequency reciprocating applications.

03
03

Low-Friction Movement

When matched with suitable linear bearings, Wangong linear shafts help achieve low-friction linear movement. This reduces drive resistance and improves operating smoothness in automation equipment and mechanical modules.

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04

Stable Dimensional Accuracy

The outer diameter tolerance, roundness, and surface finish of a linear shaft directly affect bearing fit. Stable dimensional control helps reduce clearance, vibration, and abnormal wear.

05
05

Smooth Surface Finish

A smooth surface helps reduce friction, noise, and wear. This is especially important when the shaft is used with ball-type linear bearings in repeated motion systems.

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06

Flexible Installation and Customization

Wangong can provide standard and customized linear shafts according to customer requirements. Custom options may include cutting, drilling, tapping, grooving, chamfering, step turning, and other end-machining services.

Advantages of Linear Shafts

A linear shaft is not the most complex linear motion component, but it is one of the most practical. It provides an effective balance between performance, cost, installation flexibility, and maintenance convenience.

01
01

Accurate Linear Guidance

A linear shaft provides a stable straight-line path for moving components. It helps reduce shaking and misalignment, making it suitable for 3D printers, testing platforms, packaging machines, robotic modules, and light automation systems.

02
02

Smooth Operation and Low Friction

When combined with linear bearings, a linear shaft enables smooth rolling motion with relatively low friction. Compared with simple sliding structures, this design improves motion efficiency and reduces resistance.

03
03

Simple Structure and Controlled Cost

Compared with linear guide rails, linear shafts have a simpler structure and are often easier to install. They are suitable for applications that require moderate accuracy, light-to-medium loads, and cost-effective design.

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04

Easy Maintenance

Linear shaft systems are usually easy to inspect, clean, lubricate, and replace. If wear occurs, the shaft or bearing can often be replaced separately, helping reduce maintenance cost.

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05

Wide Application Range

Wangong linear shafts can be used in automation equipment, CNC machinery, packaging systems, robotics, printing equipment, medical devices, inspection machines, 3D printers, and many other industrial applications.

Common Types of Linear Shafts

Linear shafts can be classified by structure, material, surface treatment, and dimensional standard. At Wangong, core linear shaft types are developed to meet different requirements for rigidity, weight, compatibility, and installation.

01
01

Solid Linear Optical Shafts

Solid linear optical shafts, such as HS/SF series metric shafts and SI series imperial shafts, are made from solid round steel through precision machining and hardening. They offer excellent rigidity, stable load-bearing capacity, and a robust structure.

Solid linear shafts are the most widely used type and are suitable for general-purpose linear motion applications where strength, durability, and standard compatibility are required.

02
02

Hollow Linear Optical Shafts

Hollow linear optical shafts, also known as the SP series, are manufactured from hollow tubing. Their main advantage is lightweight design.

While maintaining sufficient rigidity, hollow shafts reduce the weight of moving parts and can provide internal space for wiring, air pipes, or other components. They are suitable for automation equipment, robotic systems, and applications where weight reduction or integrated routing is important.

03
03

Metric Standard Linear Shafts

Metric standard linear shafts, including HS/SF series solid shafts and SP series hollow shafts, follow millimeter-based dimensional standards. They are widely used in domestic and international equipment and are compatible with most mainstream linear bearings, supports, and accessories.

Metric shafts are a mainstream choice for new machine design, automation equipment, and standard industrial applications.

04
04

Imperial Standard Linear Shafts

Imperial standard linear shafts, also known as the SI series, follow inch-based dimensional standards. They are mainly used for applications requiring compatibility with imported European and American equipment, existing machine designs, or special replacement parts.

05
05

Chrome-Plated Linear Shafts

Chrome-plated linear shafts have a hard chrome layer on the surface. This improves wear resistance, corrosion resistance, and surface hardness, making them suitable for applications requiring enhanced surface protection.

06
06

Hardened Linear Shafts

Hardened linear shafts are treated to improve surface hardness and wear resistance. They are suitable for frequent reciprocating motion, higher operating frequency, and applications with stricter durability requirements.

07
07

Stainless Steel Linear Shafts

Stainless steel linear shafts provide better corrosion resistance. They are suitable for humid environments, clean equipment, food machinery, medical equipment, and mildly corrosive working conditions.

08
08

End-Machined Linear Shafts

End-machined linear shafts can be customized according to customer drawings. Common machining options include drilling, tapping, turning, milling grooves, chamfering, and stepped ends to support easier installation and positioning.

Linear Shaft vs. Linear Guide Rail

Linear shafts and linear guide rails are both used for linear guidance, but they differ in structure, load capacity, rigidity, accuracy, and cost.

Comparison Item Linear Shaft Linear Guide Rail
Structure Cylindrical shaft used with linear bearings Profiled rail used with guide blocks
Load Capacity Suitable for light-to-medium loads Higher load capacity and stronger rigidity
Accuracy Suitable for medium-precision applications Suitable for high-precision positioning
Torsional Rigidity Single shaft has limited anti-twist ability Better resistance to moment loads
Installation Simple installation and easy adjustment Requires accurate mounting surface and alignment
Cost Lower cost and good value Higher cost
Maintenance Easy to clean, lubricate, and replace Requires careful cleaning and lubrication
Typical Applications 3D printers, light automation, packaging machines CNC machines, precision stages, robots, high-load equipment

In general, linear shafts are suitable for simple structures, cost-sensitive designs, light-to-medium loads, and medium-precision systems. Linear guide rails are better suited for high-load, high-rigidity, high-precision, and high-speed positioning applications.

As Wangong manufactures both linear shafts and other precision transmission components, we understand that the right choice depends on the equipment’s load, speed, rigidity, accuracy, installation space, and cost requirements.

How to Choose a Linear Shaft

Proper selection directly affects the motion accuracy, service life, noise level, and maintenance cost of the equipment. When choosing a linear shaft, the following factors should be considered.

01
01

Shaft Diameter

A larger diameter usually provides better rigidity and load capacity, but it also increases weight and cost. The correct shaft diameter should be selected based on load, stroke length, mounting method, and allowable deflection.

02
02

Length and Deflection

Long shafts are more likely to bend under load. For long-stroke systems, deflection should be evaluated. A supported shaft or additional support may be required.

03
03

Solid or Hollow Structure

Solid shafts are suitable for applications requiring higher rigidity and load-bearing capacity. Hollow shafts are better for weight-sensitive designs or applications requiring internal wiring or air pipe routing.

04
04

Metric or Imperial Standard

Metric shafts are widely used in mainstream industrial equipment and automation systems. Imperial shafts are suitable for replacement, maintenance, or equipment designed according to inch-based standards.

05
05

Material

Common materials include bearing steel, carbon steel, and stainless steel. Material selection should be based on load, wear resistance, corrosion resistance, and environmental conditions.

06
06

Surface Treatment

Chrome plating, hardening, polishing, and other treatments can improve wear resistance, corrosion resistance, and surface quality.

07
07

Accuracy Requirements

Important accuracy factors include outer diameter tolerance, roundness, straightness, and surface roughness. Higher precision applications require better machining quality and more careful installation.

08
08

Matching Bearing Type

The linear shaft must match the linear bearing or slider. Shaft diameter, tolerance, bearing inner diameter, load rating, and lubrication requirements should all be confirmed.

09
09

Working Environment

Dust, moisture, corrosive gases, high temperature, or cleanroom requirements may affect material and surface treatment selection.

Installation Steps for Linear Shafts

Correct installation helps prevent jamming, uneven wear, noise, vibration, and positioning errors.

01

Inspect the shaft surface

Check for scratches, rust, bending, dents, or contamination.

02

Verify dimensions

Confirm that shaft diameter, length, straightness, and end machining match the drawings.

03

Clean all mounting parts

Clean the machine base, shaft supports, support rails, and linear bearings.

04

Install shaft supports or support rails

Fix the supports or support rails onto the machine base and perform initial positioning.

05

Install the linear shaft

Place the shaft into the supports or support rail. Do not fully tighten the fasteners at first.

06

Check parallelism and levelness

For dual-shaft systems, use measuring tools to check parallelism between the two shafts.

07

Install the linear bearing or slider

Slowly mount the bearing or slider onto the shaft. Avoid hammering or forced installation.

08

Adjust movement smoothness

Move the slider manually through the full stroke and check for jamming, noise, or sudden resistance.

09

Tighten fasteners

Tighten bolts, shaft supports, and end-fixing components to the specified torque.

10

Apply lubrication

Add suitable grease or oil according to the bearing and equipment requirements.

11

Perform low-speed trial operation

Check for abnormal vibration, noise, heat, or uneven wear.

12

Record installation data

Record the assembly condition, lubrication method, and maintenance cycle.

Installation should follow machine drawings, manufacturer instructions, and mechanical safety standards. For high-speed, high-precision, or heavy-load systems, more accurate alignment inspection is recommended.

A linear shaft is a fundamental precision component in linear motion systems. It supports, guides, positions, and carries moving parts while helping mechanical systems achieve smooth and low-friction linear movement.

At Lishui Wangong Precision Machinery Co., Ltd., linear shafts are manufactured through a systematic process that combines material control, precision machining, heat treatment, surface finishing, and full-process inspection. Wangong provides reliable linear shaft solutions for automation, CNC machinery, robotics, packaging equipment, inspection systems, and other industrial applications.

Compared with linear guide rails, linear shafts offer a simpler structure, easier installation, lower cost, and convenient maintenance. They are especially suitable for light-to-medium loads, medium-precision requirements, and flexible machine structures.

When selecting a linear shaft, key factors include shaft diameter, length, structure, material, surface treatment, accuracy grade, load condition, installation method, and working environment. With proper selection, correct installation, and regular maintenance, Wangong linear shafts can help customers achieve stable motion performance and long-term equipment reliability.