CNC Gear Hobbing for Custom Brass Spur Gears

The brass spur gears shown here were custom manufactured for a customer in the United States. Each gear combines Module 0.5 external teeth, a machined center bore and an internal keyway, requiring both gear hobbing and secondary machining to complete the part.

For this type of component, producing the tooth profile is only one part of the manufacturing work. The gear teeth, bore and keyway need to follow the same engineering drawing so that the finished gear fits the shaft and meshes correctly with its mating component.

YS Precision provides CNC gear hobbing services for custom and non-standard gears, combining gear blank preparation, hobbing and additional CNC machining according to customer specifications.

Brass Spur Gear Project

Starting with a Properly Machined Gear Blank

Before gear hobbing begins, the brass material needs to be prepared to the required blank dimensions.

Depending on the drawing, machining at this stage establishes the faces, gear width, center bore and other reference geometry. These features provide the foundation for the subsequent tooth-cutting operation.

For this component, a typical manufacturing route is:

Brass Stock → Gear Blank Machining → Bore Machining → CNC Gear Hobbing → Keyway Machining → Deburring → Inspection

The actual machining sequence is determined by the part geometry and tolerance requirements.

Preparing the blank correctly is important because the external teeth do not work independently from the center features. Their relationship affects how the finished gear locates and rotates after assembly.

CNC Gear Hobbing for External Spur Teeth

The external teeth are generated using CNC gear hobbing.

For this project, the specified module is 0.5, giving the gear a relatively fine tooth profile. The hobbing setup follows the gear data defined by the customer, including tooth count, pressure angle and gear width.

During hobbing, the cutter and gear blank rotate in a synchronized relationship while the tooth spaces are progressively generated around the circumference.

This process is well suited to external spur gears and provides an efficient manufacturing route for custom gears that need consistent tooth geometry across multiple parts.

Most importantly, the gear is manufactured from defined engineering parameters rather than by approximating the visible tooth shape.

Bore-to-Tooth Relationship Is Part of the Gear Function

The center bore determines how the finished gear locates on its shaft.

For this reason, the bore and external teeth should not be treated as unrelated machining features. Even if individual dimensions are within specification, their relationship can influence how the gear rotates and engages in the final mechanism.

Where required by the drawing, bore tolerance, runout or other reference requirements can be incorporated into the manufacturing and inspection plan.

This is an important difference between simply cutting gear teeth and providing a complete custom gear machining service.

Internal Keyway for Shaft Connection

The internal keyway visible in each gear provides a positive mechanical connection to a keyed shaft.

Its width and depth are manufactured according to the customer's shaft and key specifications so that the gear can be correctly positioned and transmit torque after assembly.

The finished component therefore combines three functional elements:

Spur Gear Teeth + Center Bore + Internal Keyway

By completing these operations within one manufacturing program, the customer can source a finished gear rather than coordinating gear cutting and secondary machining separately.

Manufacturing Gears That Need to Mesh Together

The photograph shows two brass spur gears engaged as a mating pair.

For mating gears, the tooth systems need to be compatible. Module and pressure angle are among the basic parameters that need to correspond, while tooth count contributes to pitch diameter and the required transmission ratio.

This makes the engineering drawing particularly important for custom gear manufacturing.

For a typical gear hobbing project, we review:

Module · Tooth Count · Pressure Angle · Gear Width · Bore · Keyway · Material · Tolerances

If the application includes specific requirements for backlash, runout or gear accuracy grade, these should also be identified on the drawing.

Why Brass Is Used for This Custom Gear

Brass offers good machinability and corrosion resistance and is used for many small gears and mechanical transmission components.

Its machinability is particularly useful for a component like this because several operations need to be completed on the same part, including blank preparation, bore machining, fine-tooth hobbing and keyway machining.

The specific brass grade should still follow the customer's engineering requirements. Load, speed, lubrication, mating material and operating conditions can all influence material selection.

Inspection Based on Drawing Requirements

Different gear applications require different levels of accuracy, so inspection should follow the actual engineering specification rather than a generic "high precision" standard.

Depending on the drawing, inspection for a custom hobbed gear can include:

• bore diameter;
• gear width;
• keyway dimensions;
• specified dimensional features;
• runout requirements;
• drawing-defined tooth characteristics.

Where two gears are supplied as a mating set, functional engagement can also be evaluated when required.

This keeps inspection focused on the features that influence fit, rotation and gear operation.

CNC Gear Hobbing for Custom Production Requirements

Non-standard gears are often required in quantities that cannot be sourced conveniently from standard catalogs.

Some projects begin with a limited quantity for mechanism testing or equipment assembly and later move into repeat production after the design is confirmed.

YS Precision supports prototype gear machining, small-batch gear hobbing and production orders according to customer requirements.

Once the manufacturing route is established, subsequent batches can follow the approved drawing, material specification and inspection requirements.

Custom CNC Gear Hobbing Services

YS Precision provides custom CNC gear hobbing and gear machining services for drawing-based mechanical components.

Depending on the gear design, manufacturing can combine:

Gear Blank Machining · CNC Turning · Bore Machining · CNC Gear Hobbing · Keyway Machining · Deburring · Inspection

For this U.S. project, the result is a complete Module 0.5 brass spur gear with hobbed external teeth, a center bore and an internal keyway manufactured according to the customer's engineering requirements.

For a new gear project, please send your 2D engineering drawing and 3D CAD file where available. Gear type, module, tooth count, pressure angle, gear width, bore, keyway, material, tolerances and required quantity are particularly useful for manufacturing review and quotation.