Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
When your motion-control build demands tight tolerances and reliable torque transfer, undersized or poorly machined gears become the weakest link. Engineers, makers, and hobbyists working on CNC machines, robotic arms, and compact automation assemblies need a Mod 0.5 brass pinion spur gear that holds its bore dimension, meshes cleanly, and resists wear over thousands of cycles.
These Mod 0.5 brass pinion spur gears are machined from solid brass stock and hardened for extended service life. Each gear features a precisely reamed bore ranging from 4 mm to 12 mm (approximately 0.157 in to 0.472 in) and a radial set screw for secure shaft retention. Tooth counts span 20 to 60 teeth, giving an outer diameter range of approximately 11 mm to 31 mm (0.43 in to 1.22 in) at 0.5 module pitch.
Typical use cases include small-format CNC router axis drives, servo-driven robotic finger joints, and compact gear-reduction stages in 3D printer extruder assemblies. The consistent 0.5 module tooth profile also makes these gears a reliable replacement for worn pinions in RC vehicle differentials and clock-mechanism prototypes.
| Module (Pitch) | 0.5 |
|---|---|
| Material | Brass (hardened) |
| Tooth Count | 20 / 22 / 24 / 25 / 28 / 30 / 32 / 35 / 40 / 50 / 60 Teeth |
| Bore Diameter | 4 mm / 5 mm / 6 mm / 7 mm / 8 mm / 10 mm / 12 mm (See variant options) |
| Outer Diameter (approx.) | ~11 mm – ~31 mm (0.43 in – 1.22 in), varies by tooth count |
| Pressure Angle | 20° (standard Mod 0.5) |
| Shaft Retention | Radial set screw (included) |
| Gear Type | Spur (straight tooth) |
| Finish | Natural brass / hardened surface |
| Pack Quantity | 1 PCS or 2 PCS (See variant options) |
| Weight (per piece) | See variant options |
Select tooth counts based on your desired gear ratio. Divide the driven gear's tooth count by the driving pinion's tooth count to get the ratio. For example, a 20-tooth pinion driving a 60-tooth gear gives a 3:1 reduction. Smaller pinions (20–25T) suit high-reduction stages; larger pinions (40–60T) work better in near-1:1 or speed-increasing configurations.
Measure your motor or drive shaft diameter with a caliper before ordering. Available bores are 4, 5, 6, 7, 8, 10, and 12 mm. Choose the bore that matches your shaft exactly — the set screw compensates for minor fit variation but is not a substitute for a correctly sized bore.
These Mod 0.5 brass pinion spur gears are hardened to improve surface wear resistance and are suitable for light-to-moderate continuous-duty applications such as small CNC routers, 3D printer extruders, and robotic joints. For heavy-load or high-torque industrial drives, consider steel gears of the same module.
Brass offers moderate natural corrosion resistance and performs well in indoor environments with occasional humidity exposure. For outdoor or marine applications where prolonged moisture contact is expected, apply a light machine oil or consider stainless-steel alternatives for critical assemblies.
Yes. The 0.5 module (Mod 0.5) tooth profile is an internationally standardized metric gear standard. These pinions will mesh correctly with any Mod 0.5 spur gear, rack, or internal gear regardless of brand, provided the pressure angle is 20° (the most common standard). Always confirm the mating gear's module and pressure angle before assembly.
Order 1 PCS for a single-axis replacement or prototype build. Choose the 2 PCS pack when you need matched pairs for dual-axis drives, mirrored gearboxes, or to keep a spare on hand. The 2 PCS variants are priced lower per piece than buying two individual units, making them the better value for paired applications.
The set screw is threaded into a radial hole in the gear hub. Use a hex (Allen) key of the appropriate size — typically 1.5 mm or 2 mm for Mod 0.5 gears. Slide the gear onto the shaft, align it to the desired position, then tighten the set screw firmly. Apply a small drop of thread-locking compound if vibration is a concern.
