Focusing on the design, manufacturing processes, heat treatment techniques, and key quality control points for all types of standard and non-standard gears.
| Parameter | Specification |
| Spline Standard | GB/T 3478, DIN 5480, ANSI B92.1, etc. |
| Module / Diametral Pitch | Customizable |
| Pressure Angle | 30°, 37.5°, 45°, and other angles available |
| Shaft Diameter | Customizable |
An involute spline shaft is a transmission shaft with involute spline teeth machined around its outer circumference. It normally works with a matching internal spline sleeve to form a spline connection, allowing multiple tooth flanks to share torque while providing reliable connection and axial positioning.
Compared with conventional keyed shafts, involute spline shafts distribute loads across multiple teeth, providing good load capacity, stable engagement, and interchangeability. Depending on the equipment and operating conditions, tooth count, module, pressure angle, shaft diameter, spline length, fit tolerances, material, and heat treatment can be customized. Drawing-based, sample-based, and non-standard machining are also available.
An involute spline shaft consists mainly of the shaft body and spline section, with teeth evenly distributed around the shaft according to the applicable spline standard. Key parameters such as tooth count, module, pressure angle, shaft diameter, and spline length are determined by the required standard and mating conditions to ensure proper assembly with the internal spline sleeve.
An involute spline shaft normally works with a matching internal spline sleeve, transmitting torque through tooth flank contact. Depending on the application, the connection can be designed as either fixed or axially sliding. Proper control of tooth geometry, fit tolerances, and centering method helps maintain stable power transmission and reliable connection.
Involute spline shafts provide good torsional strength, fatigue resistance, and connection rigidity, making them suitable for medium- to high-torque and continuous-duty applications. Proper material selection, heat treatment, and fit accuracy can further improve wear resistance, fatigue performance, and operating stability.
Involute spline shafts combine standardized tooth geometry, reliable torque transmission, and stable mating performance. They are widely used in automotive transmissions, construction machinery, agricultural machinery, gear reducers, machine tools, and industrial transmission systems.
Spline parameters, centering method, fit tolerances, material, and heat treatment can be customized according to specific transmission and connection requirements.
| Parameter | Standard Mass-Production Model (General Service) | High-Precision Custom Model (Precision Transmission) |
| Core Transmission Specifications | ||
| Spline Type | Involute External Spline | High-precision involute spline; non-standard designs available |
| Spline Standard | Specified according to drawing and mating spline standard | GB/T 3478, DIN 5480, ANSI B92.1, and other standards supported |
| Module / Diametral Pitch | Designed according to transmitted torque and structural requirements; module or DP available | Optimized for load capacity, transmission performance, and precision fit |
| Pressure Angle | Determined according to the applicable standard and mating spline | Determined according to the mating internal spline and accuracy requirements |
| Number of Teeth | Designed according to torque, shaft diameter, and structural requirements | Optimized for load, service life, and fit accuracy |
| Shaft Diameter | Designed according to installation space, load, and mating spline sleeve | Precision control of shaft diameter, concentricity, and fit tolerances |
| Spline Length | Customized according to connection length and equipment structure | Optimized according to load and precision fit requirements |
| Fit Type | Fixed or axial sliding connection | Precision fixed or sliding fit |
| Fit & Accuracy Specifications | ||
| Centering Method | Flank or major diameter centering, according to standard and mating structure | Precision control of centering accuracy and fit |
| Accuracy Grade | Determined according to application, fit tolerances, and applicable standard | High-precision dimensional, tooth profile, and fit control available |
| Profile Accuracy | Standard precision machining | Optimized tooth profile, lead, and tooth thickness accuracy |
| Fit Accuracy | Standard spline fit control | Precision control of fit tolerances, concentricity, and backlash |
| Materials & Manufacturing Capabilities | ||
| Material Selection | 45 Steel, 40Cr, 42CrMo, stainless steel, and other materials | 42CrMo, 20CrMnTi, 20CrMo, and other high-performance alloy steels |
| Heat Treatment | Quenching and tempering, induction hardening | Induction hardening, carburizing and hardening, and other surface hardening treatments |
| Machining Processes | Gear hobbing, shaping, cold rolling, and sizing | Precision hobbing, shaping, spline grinding, cylindrical grinding, and finishing |
| Surface Treatment | Black oxide, phosphating, and rust-preventive oil coating | Precision corrosion protection and special surface treatments |
| Remarks | The above are standard machining parameter ranges for our involute spline shafts. Special sizes and non-standard structures can be custom-made according to your drawings or samples. For a quotation, please provide the spline standard, module or DP, pressure angle, number of teeth, shaft diameter, material, accuracy requirements, and quantity. | |
High-quality blanks are forged and normalized to eliminate internal stress and stabilize material structure.
Turning, milling and hobbing/shaping are applied to form the target tooth profile with strict accuracy control.
Carburizing quenching or tempering processes to improve tooth surface hardness and core toughness.
Grinding of tooth flanks, bores and datum faces to correct deformation and enhance meshing precision.
Full-dimensional verification by gear measuring center and CMM to qualify products before release.
Professional anti-rust and protective packaging to keep products intact during storage and transit.
High-precision gear grinding delivers tooth surface roughness as low as Ra 0.4, with tight meshing, low vibration and noise for smoother equipment operation.
Premium materials matched with precise heat treatment ensure wear-resistant tooth surfaces and impact-resistant core, cutting maintenance and replacement costs.
Custom solutions for high-speed heavy load, corrosion resistance and food-grade scenarios, eliminating trial-and-error costs in product selection.
Scaled production supports tiered pricing for bulk orders with consistent quality; full-process control guarantees stable lead time and complete after-sales support.
Representative Grades: 45 Steel / C45
45 steel offers a good balance of mechanical properties, machinability, and cost. After quenching and tempering, it provides good strength and toughness, making it suitable for involute spline shafts used in general machinery, agricultural equipment, and medium-load transmission systems.
Representative Grades: 40Cr, 42CrMo
40Cr and 42CrMo provide high strength, toughness, and fatigue resistance. Quenching and tempering or induction hardening can improve spline flank hardness and wear resistance, making them suitable for construction machinery, gear reducers, and medium- to high-load industrial transmission systems.
Representative Grades: 20CrMnTi, 20CrMo
20CrMnTi and 20CrMo develop a hard surface layer and tough core after carburizing and hardening, providing good wear resistance, fatigue strength, and impact resistance. They are suitable for automotive transmissions, heavy-duty machinery, and high-load spline shafts for continuous operation.
Representative Grades: 304, 316, 420
Stainless steel offers good corrosion resistance and environmental durability. 304 and 316 are suitable for light-load transmission in humid or corrosive environments, while 420 can achieve higher hardness and wear resistance through heat treatment. Typical applications include food, pharmaceutical, and chemical equipment.
Representative Grade: 38CrMoAl
38CrMoAl can achieve high surface hardness, wear resistance, and dimensional stability after nitriding while retaining good core toughness. It is suitable for precision gear reducers, machine tools, automation equipment, and other high-precision transmission systems.
Representative Grades: QT450, QT500
Ductile iron combines good strength, wear resistance, and vibration damping. It is suitable for larger involute spline shafts used at low speeds and under medium loads, including general machinery, agricultural equipment, and industrial transmission systems.
In transmissions, drive shafts, clutches, and other automotive components, involute spline shafts provide reliable connections between shafts, gears, and sleeves. Their stable torque transmission and good interchangeability make them suitable for both mass production and replacement applications.
In construction machinery, tractors, harvesters, and other agricultural equipment, involute spline shafts connect drive shafts, transmission shafts, and actuating components. Their ability to handle torque and fluctuating loads makes them suitable for long-term operation under demanding working conditions.
In gear reducers, transmission boxes, and industrial drive systems, involute spline shafts connect input shafts, output shafts, and other transmission components. Their stable fit and reliable load transmission make them suitable for medium- to high-torque and continuous-duty applications.
In CNC machine tools, automation equipment, and precision mechanical systems, involute spline shafts are used where accurate fits, reliable positioning, or axial movement are required. Precise control of spline dimensions and fit tolerances helps improve connection accuracy and operating stability.
In industrial robots, automated actuators, and precision motion equipment, involute spline shafts connect drive shafts with actuating components. They support reliable torque transmission and repeatable positioning, with spline dimensions and fit accuracy customizable to specific equipment requirements.
In lifting equipment, conveyors, and material handling systems, involute spline shafts connect transmission shafts with gears, couplings, and other drive components. Their multi-tooth load sharing provides reliable torque transmission for medium- to high-torque and continuous-duty applications.
Inner VCI vacuum anti-rust process fully seals tooth flanks and critical machined surfaces, effectively resisting salt spray and moisture during ocean and air freight to keep precision gears corrosion-free throughout long-distance transit.
We select cost-effective logistics channels with stable transit time and controlled costs. Full logistics tracking is available with real-time status updates to ensure reliable and punctual delivery.
All products are covered by a 1-year warranty. Quality defects caused by non-human factors are fully guaranteed, removing your procurement concerns.
Our professional technical and after-sales team is always available to respond quickly to inquiries and after-sales needs, and efficiently resolve issues during installation and operation.
We support full-parameter OEM/ODM customization based on 2D/3D drawings or physical samples, including module, tooth profile, material and heat treatment specifications. You only need to provide core gear parameters, detailed drawings or physical samples to start the customization process.
You can send physical samples to us via international courier. Upon receipt, we will complete full-dimensional measurement and parameter verification, then arrange sample production after confirming the solution, ensuring the finished product fully matches the original in installation dimensions and transmission performance.
Prototype orders usually ship within 15–25 days, subject to heat treatment and grinding scheduling. Lead time for bulk orders will be confirmed after process finalization, with stable and well-managed production schedules.
We adopt a tiered pricing policy — the larger the order quantity, the more favorable the unit price. All orders follow the same production and quality inspection standards with strict accuracy control. Quality will never be compromised for larger order volumes.
We can include dimensional inspection reports, hardness test records and material certificates with each shipment. For high-precision key projects, professional inspection data from CMM and gear measuring centers is also available.
All products come with a 1-year warranty covering material defects and manufacturing quality issues under normal use. We also have a professional technical team to provide full-process consultation and selection support.
Spur gears feature a simple structure and no axial load, ideal for medium-low speed general transmission with higher cost-effectiveness. Helical gears run smoother with lower noise and higher load capacity, suitable for high-speed heavy-duty applications. We can recommend the optimal solution based on your actual requirements.
+86 184 3796 0706 
info@destinytrans.com 
