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When a stripped or undersized gear brings your drive system to a halt, every hour of downtime costs you. Engineers, robotics builders, and machine designers who need a reliable, drop-in Module 5 spur gear know that tooth count and material integrity are non-negotiable. These Module 5 spur gears are engineered for demanding power-transmission applications where dimensional accuracy and surface hardness directly affect system longevity.
Each gear is machined from C45 medium-carbon steel and subjected to a hardening process that raises surface durability while retaining a tough core. The flat-face cogwheel profile follows standard Module 5 geometry, with a tooth pitch of 5 mm (0.197 in) and available tooth counts from 12 to 35 — corresponding to pitch circle diameters ranging from approximately 60 mm (2.36 in) to 175 mm (6.89 in). Bore diameter and keyway dimensions vary by tooth count; see variant options for exact bore specs.
Typical use cases include CNC router spindle drives requiring a module 5 motor pinion gear replacement, robotic arm joint actuators where a hardened steel spur gear reduces backlash, and industrial conveyor or gearbox assemblies that demand a C45 steel cogwheel with consistent tooth profile across production runs.
| Module | 5 |
|---|---|
| Tooth Count Range | 12 – 35 teeth (see variant options) |
| Pitch Circle Diameter | See variant options (60 mm – 175 mm / 2.36 in – 6.89 in) |
| Tooth Pitch | 5 mm (0.197 in) |
| Pressure Angle | 20° |
| Material | C45 Medium-Carbon Steel |
| Surface Treatment | Hardened |
| Gear Type | Spur Gear (Flat Face) |
| Bore Diameter | See variant options |
| Hub Width / Face Width | See variant options |
| Sold As | 1 pc per unit |
The tooth count determines your gear ratio when paired with a mating gear. Divide the driven gear tooth count by the driving gear tooth count to get the ratio. For example, pairing a 12-tooth pinion with a 36-tooth gear gives a 3:1 reduction. Select the tooth count that achieves your target output speed and torque based on your motor's RPM and the load requirements of your machine.
Module (Mod) is the standardized unit of gear tooth size used in metric gear systems. Module 5 means the pitch circle diameter equals 5 mm × tooth count. These gears will mesh correctly with any other Module 5 spur gear, rack, or pinion that follows ISO/DIN standards. They are not compatible with Module 4, Module 6, or imperial diametral pitch gears.
C45 steel spur gears with surface hardening typically achieve a surface hardness in the range of 45–55 HRC at the tooth contact zone, while the core remains at a lower hardness (approximately 20–30 HRC) to retain toughness and resist shock loads. Exact hardness values depend on the specific heat treatment batch; contact us to confirm if your application has a strict hardness requirement.
C45 carbon steel is not inherently corrosion-resistant. For outdoor, humid, or washdown environments, we recommend applying a compatible gear lubricant or grease to the tooth surfaces and housing the gear in a sealed enclosure. If your application requires corrosion resistance, consider stainless steel or nylon gear alternatives, or apply a protective coating after installation.
Bore diameter and keyway dimensions vary by tooth count and are listed in the variant options on this page. Please select your tooth count variant and review the detailed dimension drawing before ordering. If you need a custom bore size, the C45 steel material is machinable and can be bored out by a local machine shop to your required shaft diameter.
Yes. The flat-face hub design is well-suited for direct mounting on motor output shafts. Verify that your motor shaft diameter matches the bore of the selected variant, and use a set screw or key (if a keyway is present) to secure the gear axially. For high-speed servo applications, confirm that the gear's pitch circle velocity does not exceed the rated surface speed for the lubrication method you are using.
For Module 5 gears, the pitch circle diameter (PCD) is calculated as: PCD = Module × Tooth Count = 5 × Z (mm). For example, a 20-tooth gear has a PCD of 100 mm (3.94 in), and a 30-tooth gear has a PCD of 150 mm (5.91 in). Use this formula to match center distances in your gearbox layout before selecting your variant.
