A gear hobbing cutter is a specialized cutting tool used in gear hobbing—a machining process that produces spur, helical, and worm gears. The cutter (or "hob") has helical cutting teeth that progressively generate the gear profile through a synchronized rotary motion with the workpiece.
1. Types of Gear Hobbing Cutters
By Design
| Type | Description | Applications |
| Straight Tooth Hob | Teeth parallel to the axis; simplest form. | Low-precision spur gears. |
| Helical Tooth Hob | Teeth at an angle (like a worm); better chip evacuation. | Helical & high-precision gears. |
| Chamfered Hob | Includes chamfers to deburr gear edges during cutting. | Automotive & mass production. |
| Gashed Hob | Deep gashes between teeth for better chip clearance in heavy cuts. | Large module gears (e.g., mining). |
By Material
HSS (High-Speed Steel) Hobs – Economical, used for soft materials (aluminum, brass).
Carbide Hobs – Harder, longer life, used for hardened steels & high-volume production.
Coated Hobs (TiN, TiAlN) – Reduce friction, extend tool life in tough materials.
2. Key Parameters of a Gear Hob
Module (M) / Diametral Pitch (DP) – Defines tooth size.
Number of Starts – Single-start (common) vs. multi-start (faster cutting).
Pressure Angle (α) – Typically 20° (common) or 14.5° (older systems).
Outside Diameter – Affects rigidity & cutting speed.
Lead Angle – Matches the helix angle for helical gears.
3. How Gear Hobbing Works?
Workpiece & Hob Rotation – The hob (cutter) and gear blank rotate in sync.
Axial Feed – The hob moves axially across the gear blank to cut teeth progressively.
Generating Motion – The hob's helical teeth create the correct involute profile.
Advantages of Hobbing
✔ High production rates (vs. shaping or milling).
✔ Excellent for spur, helical, and worm gears.
✔ Better surface finish than broaching.
4. Applications of Gear Hobs
| Industry | Use Case |
| Automotive | Transmission gears, differentials. |
| Aerospace | Engine & actuator gears. |
| Industrial | Gear pumps, reducers, heavy machinery. |
| Robotics | Precision motion control gears. |
5. Selection & Maintenance Tips
Choose the right hob type (HSS for soft materials, carbide for hardened steel).
Optimize cutting speed & feed rate (depends on material & module).
Use coolant to extend tool life (especially for carbide hobs).
Inspect for wear (chipped teeth, flank wear) to avoid poor gear quality.
6. Leading Gear Hob Manufacturers
Gleason (Precision hobs for spiral bevel & cylindrical gears)
LMT Tools (High-performance HSS & carbide hobs)
Star SU (Custom hobs for specialized applications)
Nachi-Fujikoshi (Japan, high-quality coated hobs)
Post time: Aug-15-2025