Gear blanks are the foundation of high-quality gear manufacturing. Before hobbing, shaping, or grinding, the accuracy of the gear blank directly determines the final gear’s concentricity, load distribution, and service life.
Compared with ordinary disc parts, a gear blank typically requires:
- · High coaxial accuracy between outer diameters and inner bores
- · Stable positioning of evenly distributed holes
- · Consistent step heights and flatness
- · A machining process that can be reliably repeated in batch production
In this case study, we present the machining of a change gear blank using a four-axis machining center, demonstrating how a well-integrated tooling and workholding system ensures precision, stability, and process consistency.
I. Gear Blank Overview and Machining Challenges
Based on the engineering drawing, this gear blank includes the following typical features:
- · Multiple stepped outer diameters
- · A deep internal bore with strict coaxiality requirements
- · Two sets of evenly distributed through holes
- · Datum-controlled faces and step heights
- · Chamfers and transition radii for subsequent gear processes
From a machining perspective, the main challenges are:
- 1. Maintaining coaxiality between outer diameters and the internal bore
- 2. Ensuring accurate angular positioning of distributed holes
- 3. Preventing cumulative errors caused by multiple setups
These requirements make the gear blank an ideal candidate for four-axis machining.
II. Why a Four-Axis Machining Center Was Selected
Although the gear blank has rotational symmetry, using a four-axis machining center provides clear advantages over traditional multi-setup processes.
Key benefits include:
- · Single rotational datum: All circular features are machined around the same axis.
- · Indexing accuracy: Evenly distributed holes can be machined by rotary indexing rather than manual positioning.
- · Reduced setups: Fewer re-clamping operations significantly reduce cumulative error.
- · Process stability: The machining process can be standardized and repeated with confidence.
For precision-oriented gear blanks, the four-axis approach offers both quality and efficiency advantages.
III.Workholding Strategy: Self-Centering Vise + Rotary Table
Workholding plays a decisive role in gear blank accuracy.
In this project, the gear blank was clamped using a self-centering vise mounted on a four-axis rotary table. This configuration provides:
- · Automatic alignment of the workpiece center with the rotary axis.
- · Symmetrical clamping force for improved stability.
- · Consistent positioning across multiple operations.
- · Faster setup and reduced operator dependency.
By establishing a stable and repeatable rotational center, the workholding system supports high coaxial accuracy throughout the machining process.
IV. Machining Process Overview
The gear blank was machined following a structured and repeatable process flow:
- 1. Face machining to establish primary datum surfaces.
- 2. External diameter and step machining using milling operations.
- 3. Internal bore roughing and precision finishing to control concentricity.
- 4. Indexing and drilling of evenly distributed holes using the rotary axis.
- 5. Chamfering and edge finishing to prepare the part for subsequent gear processes.
All critical features were completed under a unified coordinate system, minimizing positional deviation.
V. Tooling System: Complete Coverage from One Factory
This project demonstrates the value of a complete tooling system rather than isolated tools.
The machining process utilized a full range of cutting tools, including:
- · Face milling cutters for datum surfaces.
- · Flat end mills for external profiles and steps.
- · Small-diameter end mills for corner cleanup and fine details.
- · Drills for distributed holes.
- · Boring tools for precision internal features.
- · Chamfer tools for deburring and edge finishing.
Different machining stages were supported by appropriate tool holders, such as:
- · Hydraulic tool holders for precision boring and finishing.
- · ER collet holders for general milling and drilling operations.
Because all tools, holders, and fixtures are supplied by our factory, compatibility and process stability are ensured from the start.
Meiwha CNC Vise
Meiwha CNC Milling Cutter
Meiwha CNC Tool Holder
VI. Quality Control Focus
For this gear blank, the following quality points were closely monitored:
- · Coaxiality between outer diameters and the internal bore.
- · Angular accuracy of evenly distributed holes.
- · Flatness and step height consistency.
- · Burr-free edges and clean transitions.
The combination of four-axis machining, stable workholding, and controlled tooling selection plays a critical role in meeting these requirements.
VII. We Are a Factory: Integrated Gear Blank Machining Solutions
This case reflects more than a single machining result—it demonstrates our role as a manufacturing factory capable of delivering integrated machining solutions.
We provide:
- · A complete range of milling cutters and hole-making tools.
- · Multiple tool holder solutions, including hydraulic and ER systems.
- · Self-centering vises and four-axis rotary tables for precision workholding.
Customers can supply drawings, accuracy requirements, and production targets. We respond with a coordinated solution designed to achieve stable, repeatable results in real production environments.
Machining a gear blank is not only about removing material—it is about controlling geometry, alignment, and repeatability.
By using a four-axis machining center, combined with a self-centering vise, precision tooling, and a structured process, this change gear blank was machined with high stability and consistent accuracy. The approach shown in this case provides a reliable foundation for subsequent gear cutting operations and scalable production.
If you are machining gear blanks or similar precision rotational components, contact us.
Share your drawing and requirements—we will provide a complete four-axis machining solution tailored to your application.
Post time: Jan-22-2026
