The Complete Guide: Splined Shafts

Table of Contents

I. What is a splined shaft?

Splines are mechanical components widely used in various applications, particularly those involving rotary motion. They consist of rows or teeth machined along their length to transmit torque from one component to another – known as “splines.” Splines may be internal or external in design.

Splined shafts are commonly used in automotive drivetrains, industrial machinery, and marine propulsion systems applications. Compared to other types of shafts like keyed ones, splines transmit more torque and allow for greater misalignment between components – especially important when there is some movement or vibration present since the splines help absorb these forces and protect the shaft or other components from damage.

There are various spline profiles, each tailored for a particular application. Popular options include involute, straight-sided and serrated options. When selecting one for your splines, factors like torque capacity required, misalignment present and operating conditions should all be considered when making your selection.

II. What is the function of the splined shaft?

Splined shafts play an essential role in machinery and equipment, such as:

  1. Transmitting Torque: The primary function of a splined shaft is to transmit torque from one component to another. The ridges or teeth on one spline engage with an identical spline on another component, transferring rotational force between them.
  2. Absorbing Misalignment: Splined shafts are designed to allow some misalignment between components, helping compensate for any slight differences in positioning or movement during operation and preventing excessive stress or wear on the shaft or other components.
  3. Enhancing Strength: Spun shafts feature ridges or teeth which offer extra support and rigidity, making them resistant to bending, twisting or deformation when under load.
  4. Reducing Vibration and Noise: Splined shafts can help reduce vibration and noise in machinery by creating a secure connection between components. This leads to smoother, quieter operations as well as less component wear.
  5. Simplifying Assembly and Disassembly: Splined shafts simplify assembling and disassembling machinery and equipment by allowing some degree of misalignment. This saves time while reducing the risk of component damage during maintenance or repair.

III. What are the applications of the splined shaft?

Splined shafts have many uses in applications requiring torque transmission and angular positioning. Here are some common examples:

  1. Automotive Industry: Splined shafts are commonly employed in automotive powertrain systems to transfer torque from the engine to the wheels. Additionally, they’re employed in steering mechanisms to transmit input from the steering wheel to a control system.
  2. Industrial Machinery: Splined shafts are commonly employed in various industrial machinery, such as pumps, compressors and conveyors. Additionally, they’re employed in manufacturing equipment like lathes and milling machines.
  3. Marine Industry: Splined shafts, such as those found in boat engines and propeller systems, are widely employed in maritime applications. Additionally, these splines find application in winches and other equipment on ships and oil rigs.
  4. Aerospace Industry: Splined shafts are widely used in the aerospace industry to transmit torque in aircraft engines and other critical systems.
  5. Agriculture Machinery: Splined shafts, such as tractors and harvesters, are employed in agricultural machinery to transmit torque from the engine to various components.
  6. Construction Machinery: Construction machinery utilizes splined shafts such as excavators, bulldozers, and cranes.
  7. Power Transmission: Splined shafts are essential components in many power transmission systems, such as gearboxes, differentials and transfer cases.

IV. What is the construction of a splined shaft?

A splined shaft is cylindrical in shape with longitudinal ridges and grooves called splines on its surface. These splines use corresponding ones on other components to transmit torque and maintain precise angular positioning.

Construction of a splined shaft typically involves the following steps:

  1. Material Selection: The material chosen depends on the application requirements and can range from steel, aluminum, and titanium.
  2. Machining: The shaft is machined to the desired dimensions and tolerances using turning, milling or grinding processes. Splines are typically cut into the shaft using broaching or hobbing tools.
  3. Heat Treatment: Heat treating the shaft can improve strength, hardness and wear resistance. Depending on the material and application needs, this process may include quenching, tempering or annealing.
  4. Finishing: The shaft grinds or polishes to achieve the required surface finish and dimensional accuracy.

The design of a splined shaft may vary based on application needs and may include features like keyways, threads, and chamfers for easier assembly and improved performance. Manufacturing the shaft involves precise machining and heat treatment to guarantee strength, durability, and dimensional accuracy.

V. What materials can be made of the splined shaft?

Splined shafts come in many materials depending on the application requirements. Common options for these shafts include:

  • Stainless Steel: Stainless steel is a popular material for splined shafts due to its superior strength, corrosion resistance and longevity. It finds applications in marine and aerospace applications.
  • Carbon Steel: Carbon steel is economical for splined shafts used in industrial machinery and automotive applications.
  • Alloy Steels: When higher strength and wear resistance are necessary in splined shafts, alloy steels such as chrome-molybdenum, nickel-chromium, and other alloys may be employed.
  • Aluminum Alloys: Aluminum alloys are lightweight and have excellent corrosion resistance, making them ideal for use in aerospace or other applications where weight is an issue.

Other materials commonly used for splined shafts include brass, bronze and titanium. When selecting the material for your shaft, factors like required strength, corrosion resistance, weight and cost must be considered; selecting the ideal material based on specific application demands will guarantee its durability and performance over time.

Splined shafts

VI. How to use the splined shaft?

Splined shafts come in many varieties, each with their design and application requirements. Here’s a detailed explanation of how to utilize each type:

  • Crowded Spline Shafts: Crowded spline shafts are designed to transmit high torque and resist misalignment. They have more teeth than other spline shafts, providing greater contact area and load capacity. To use crowded spline shafts, the mating component must have matching splines that fit tightly into their grooves. Once assembled, these two parts must be precisely angled together with accurate torque transmission through their splines.
  • Parallel Key Spline Shafts: Parallel key spline shafts are the most popular type of spline shaft used in many applications. They feature straight-sided keyways cut into their surface, and mating components have corresponding keys that fit tightly into these keyways. To use parallel key spline shafts, keys must be inserted into these keyways before assembly – this ensures precise angular positioning and torque transmission.
  • Involute Spline Shafts: Involute spline shafts feature teeth that transmit torque smoothly and efficiently. Their specific involute profile guarantees a constant velocity ratio between the shaft’s teeth and whatever it attaches to. To use an involute spline shaft, ensure your mating component has matching teeth that mesh tightly with those on the shaft; this ensures accurate angular positioning and torque transfer when assembled together.
  • Helical Spline Shafts: Helical spline shafts feature teeth cut at an angle to the shaft’s axis, creating a helical shape. This design offers higher load capacity, smoother torque transmission and better misalignment tolerance when assembled with matching helical teeth that mesh tightly with those on the shaft. Once assembled together, these helical teeth ensure accurate angular positioning and torque transmission.
  • Serrated Spline Shafts: Serrated spline shafts feature teeth cut into their surface in a serrated pattern, providing high torque transmission for heavy-duty applications. To use serrated spline shafts, both mating components must have matching serrations that mesh tightly with those on the shaft. When assembled together, these serrations guarantee accurate angular positioning and torque transmission.

VII. How to clean the splined shaft?

Cleaning splined shafts is an essential maintenance task that helps guarantee their optimal performance and longevity. The correct cleaning method depends on the type of splined shaft and any surface contamination present. Here’s how to do so using various methods:

  • Broaching: Broaching is a method of cutting a spline in a shaft by pulling an appropriate tool called a broach through its hole. To clean broached splined shafts, wipe their surface with either a cleaning brush or rag and wipe away any contaminants or dirt. If this proves difficult, use solvents like alcohol or acetone to dissolve contaminants before wiping with a clean rag.
  • Shaping: Shaping involves cutting a spline into a shaft with an appropriate shaping tool. To clean these shaped shafts, using either a wire brush or rag can remove any dirt and contaminants. Alternatively, solvents like kerosene or diesel fuel may dissolve contaminants which can then be wiped away with a clean rag.
  • Milling: Milling is a method of cutting a spline into a shaft with a milling cutter. To clean these milled shafts, a brush or rag will help remove any debris or contaminants. A solvent like mineral spirits may also dissolve contaminants before wiping away with a clean rag.
  • Hobbing: Hobbing is the process of cutting a spline into a shaft using a hobbing machine. To clean these hobbed shafts, use a brush or rag to remove any debris or contaminants. A solvent such as methyl ethyl ketone (MEK) or trichloroethylene (TCE) can dissolve these substances before wiping with another clean rag.
  • Rolling: Rolling creates a spline on a shaft by rolling an appropriate tool over its surface. A cleaning brush or rag can remove any dirt, while solvents like isopropyl alcohol can dissolve contaminants before wiping with a dry rag.
  • Grinding: Grinding is a technique for cutting splined shafts with a grinding wheel. A brush or rag can remove any dirt, while solvents such as acetone or brake cleaner should then be applied for dissolution before wiping away with another clean rag.
  • Extrusion: Extrusion creates a spline on a shaft by pushing out an extruding tool over its surface. To clean extruded splined shafts, use either a brush or rag to remove any dirt or contaminants; alternatively, denatured alcohol can be used as solvent to dissolve contaminants before wiping with a clean rag.

VIII. Can you offer a custom splined shaft?

As a manufacturer or supplier of splined shafts, we provide tailor-made solutions to fit the individual requirements of our customers. We collaborate closely with our customers to understand their torque, speed and load capacity requirements. By offering custom-made splined shafts, we guarantee our customers a perfect fit, improved performance, increased durability, and flexibility. Our expertise in designing and manufacturing custom-made shafts enables us to optimize their performance and aesthetics, enabling them to fit seamlessly into existing equipment or machinery. Apart from splined shafts, we also offer mold designing services, mold manufacturing, rapid prototyping and CNC machining. We have top-notch technology that helps us deliver quality to our customers globally.

Through our commitment to quality and customer satisfaction, we aim to deliver our customers the finest custom-made splined shaft solutions possible.


Splined shafts are essential components in many types of machinery and equipment, serving various important purposes. They transmit torque, absorb misalignment, enhance strength, reduce vibration and noise levels, and simplify assembly and disassembly processes. Splined shafts come in various sizes and configurations, and the choice of spline profile depends on your application-specific needs. Overall, splined shafts offer an efficient and dependable means of transmitting power and torque, which can improve the performance, dependability, and lifespan of machinery and equipment. Therefore, anyone involved in designing, manufacturing, or maintaining mechanical systems should become familiar with their characteristics and applications.


Gary Liao

Gary Liao

Gary Liao is the Engineering Manager of TDL Company and has more than 20 years of mold design experience.

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