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When a slipping or mismatched gear brings your build to a halt, you need a replacement you can trust to spec. Whether you're a CNC hobbyist dialing in a router axis, a robotics engineer prototyping a drive train, or a maker repairing a motorized project, these 1 module spur gears in 45# carbon steel give you the dimensional accuracy and material strength to get back on track without guesswork.
Each gear is machined from 45# medium-carbon steel, offering a solid balance of hardness and machinability. The module is 1 (metric), with tooth counts ranging from 15T to 24T and step (hub) diameters of 14 mm, 15 mm, 16 mm, or 17 mm (approximately 0.55–0.67 in). Bore diameters span 4 mm to 12.7 mm (approx. 0.16–0.50 in), covering a wide range of shaft sizes. Overall gear outer diameters range from approximately 17 mm to 26 mm (0.67–1.02 in) depending on tooth count.
Typical use cases include 1 mod gear rack and pinion systems for linear CNC motion, small gearbox assemblies in 3D printer extruder drives, and custom torque-reduction stages in robotics arm joints. The stepped hub design simplifies shaft alignment and set-screw retention in tight enclosures.
Machined from 45# medium-carbon steel for reliable strength and wear resistance in mechanical drive applications.
True 1 mod tooth profile ensures accurate meshing with any standard Module 1 gear, rack, or pinion without modification.
Six tooth count options (15T, 16T, 17T, 18T, 20T, 24T) let you dial in the exact gear ratio your drive system requires.
Integrated step hub (14–17 mm diameter) provides a positive shoulder for set-screw or press-fit shaft mounting in compact assemblies.
Nine bore diameter options from 4 mm to 12.7 mm accommodate a wide variety of motor and drive shaft sizes out of the box.
Available in packs of 1, 3, 5, or 10 pieces — order a single gear for a repair or stock up in bulk for prototyping runs.
| Module | 1 (metric) |
|---|---|
| Material | 45# Carbon Steel |
| Tooth Count Options | 15T, 16T, 17T, 18T, 20T, 24T |
| Bore Diameter Range | 4 mm – 12.7 mm (0.16 – 0.50 in) |
| Step (Hub) Diameter | 14 mm, 15 mm, 16 mm, 17 mm |
| Outer Diameter (approx.) | 17 mm – 26 mm (varies by tooth count) |
| Pressure Angle | 20° (standard metric) |
| Surface Finish | See variant options |
| Pack Quantity Options | 1 / 3 / 5 / 10 Pcs |
| Application | CNC, robotics, gearboxes, DIY mechanical drives |
The tooth count determines your gear ratio. A smaller pinion (e.g., 15T) driving a larger gear produces speed reduction and torque multiplication. A 15T–24T pairing gives a ratio of approximately 1.6:1. Match your tooth count to the ratio your drive system requires, and ensure both mating gears share the same module (Module 1 in this case).
Measure your motor or drive shaft diameter precisely with calipers. Select the bore that matches your shaft — available options are 4 mm, 5 mm, 6 mm, 6.35 mm (1/4 in), 7 mm, 8 mm, 10 mm, 12 mm, and 12.7 mm (1/2 in). A bore that is too large will require a bushing; a bore that is too small cannot be installed without machining.
The step diameter refers to the raised hub section of the gear that extends beyond the gear face. It provides a shoulder for axial positioning and a surface for set-screw clamping. Step diameters of 14–17 mm are available depending on the tooth count variant. Choose a step diameter that fits within your housing bore or bearing seat.
45# carbon steel offers a tensile strength of approximately 600–700 MPa in the normalized condition, making these gears suitable for light-to-medium duty continuous operation in CNC, robotics, and motorized DIY applications. For heavy shock loads or high-speed industrial use, consider hardened or alloy steel gears. Actual load capacity depends on tooth count, speed, and lubrication.
45# carbon steel has limited inherent corrosion resistance. For indoor or dry environments, the bare steel finish is adequate with periodic light lubrication. For humid or outdoor applications, apply a rust-inhibiting grease or consider a zinc-plated or stainless alternative. Do not use in prolonged contact with water without protective coating.
Yes — any gear or rack manufactured to the Module 1 metric standard with a 20° pressure angle will mesh correctly with these gears. Confirm the module and pressure angle of your existing components before ordering. Module 1 is not compatible with DP (diametral pitch) imperial gears without conversion.
If you need a single replacement gear, the 1-piece option is the most economical choice. For prototyping, where you may need to test multiple gear ratios or bore sizes, the 3- or 5-piece packs offer better per-unit value. The 10-piece pack is ideal for production runs or stocking a workshop with spares across multiple projects.
