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When your motion-control build demands consistent tooth engagement and reliable torque transfer, undersized or poorly machined gears become the weakest link in the chain. Engineers, makers, and automation hobbyists working on CNC routers, 3D printer extruder drives, robotic arms, and custom gearboxes need pinion gears that hold tight tolerances across every cycle. These 1 Mod spur gears are machined from 45# medium-carbon steel, delivering the rigidity and wear resistance that plastic or low-grade metal alternatives simply cannot match.
Each gear in this series follows Module 1 (Mod 1) standards with a flat face thickness of 10mm (0.394 in). The tooth count range spans 12 T through 25 T, with corresponding outer diameters from 14mm (0.551 in) up to 27mm (1.063 in). The bore diameter and keyway dimensions vary by tooth count — see variant options for exact bore specs. All gears feature a standard 20° pressure angle, consistent with the DIN/ISO Mod 1 gear system.
Typical use cases include: replacing worn pinion gears in 1 Mod CNC rack-and-pinion linear drives, building compact reduction stages in DIY servo gearboxes, and assembling multi-stage spur gear trains for robotics joint actuators. Long-tail applications such as "1 mod steel pinion gear for CNC router" and "Mod 1 spur gear 45 steel 10mm thick" are well served by this range.
Machined from 45# carbon steel for a balance of machinability, surface hardness, and tensile strength — suitable for moderate-load continuous-duty gear drives.
Conforms to the international Mod 1 gear standard. Meshes directly with any compatible Mod 1 rack or mating gear, simplifying system design and replacement sourcing.
Uniform 10mm (0.394 in) face width across the full 12–25 tooth range ensures consistent load distribution and straightforward axial alignment in your gearbox or drive assembly.
Fourteen tooth-count options (12 T through 25 T) with outer diameters from 14mm to 27mm let you dial in the exact gear ratio and envelope size your design requires.
Available in 1, 2, 5, 10, and 20-piece packs. Order a single gear for a repair or stock up in bulk for production runs and prototyping batches — priced to scale.
Dimensioned to standard Mod 1 specifications, making these gears a reliable drop-in replacement for worn or damaged pinions in existing CNC, robotics, and automation equipment.
| Module | 1 (Mod 1) |
|---|---|
| Pressure Angle | 20° |
| Tooth Count Range | 12 T – 25 T (14 options) |
| Outer Diameter Range | 14mm – 27mm (0.551 in – 1.063 in) |
| Face Thickness | 10mm (0.394 in) |
| Material | 45# Medium-Carbon Steel |
| Finish | See variant options |
| Bore Diameter | See variant options |
| Keyway | See variant options |
| Gear Form | Spur (straight tooth) |
| Pack Quantity | 1 / 2 / 5 / 10 / 20 Pcs |
Select the tooth count based on your required gear ratio and the available envelope space. For a given module, a higher tooth count means a larger outer diameter and a lower speed ratio when paired with a smaller pinion. Use the formula: Gear Ratio = Driven Teeth ÷ Driver Teeth. If you are replacing an existing gear, match the tooth count and module (Mod 1) of the original part.
45# medium-carbon steel offers a tensile strength typically in the range of 600–800 MPa depending on heat treatment. These gears are suited for moderate-load, continuous-duty applications such as CNC router drives, robotic joint actuators, and small gearbox stages. For heavy shock loads or high-speed industrial drives, consider hardened or alloy steel alternatives.
45# carbon steel has limited inherent corrosion resistance. For indoor or dry-environment applications, standard lubrication (grease or gear oil) provides adequate protection. For humid, outdoor, or washdown environments, consider applying a rust-inhibiting coating or selecting stainless steel gears instead.
Yes — provided your rack or mating gear is also Module 1 with a 20° pressure angle, these pinion gears will mesh correctly. Module and pressure angle must match between mating gears. If your existing system uses a different module (e.g., 0.8 Mod or 1.5 Mod), these gears will not be compatible.
Bore diameter varies by tooth count in this series. Please refer to the variant detail page or contact us to confirm the exact bore diameter for your selected tooth count before ordering. Measure your shaft diameter with calipers and allow for any keyway or set-screw retention method you plan to use.
Yes. Because the full 12–25 tooth range is available in the same Mod 1 standard, you can combine multiple tooth counts to build multi-stage spur gear reductions. Ensure adequate center-distance spacing between shafts: Center Distance = (T1 + T2) × Module ÷ 2, where T1 and T2 are the tooth counts of the mating gears.
For prototyping or a single repair, the 1 Pcs or 2 Pcs options let you validate fit and function before committing to larger quantities. For small production runs or to maintain a spare-parts inventory, the 5, 10, or 20-piece packs offer better per-unit value. Bulk packs are also useful when building symmetric gear trains that require identical pinions on multiple axes.
