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When a motion-control build demands consistent tooth engagement and reliable torque transfer, undersized or poorly machined gears become the weakest link. Engineers, makers, and automation integrators who need a dependable Module 1 spur gear will find this 45# carbon steel option covers the widest range of tooth counts in a single listing — from compact 8-tooth pinions to large 200-tooth wheels — all sharing a uniform 10 mm (0.39 in) face width for straightforward stage design.
Each gear is machined from 45# medium-carbon steel, a material widely used in mechanical power transmission for its balance of strength and machinability. The tooth profile follows the standard Module 1 (1 mm/tooth pitch) involute geometry. Face width is 10 mm (0.39 in). Bore options range from 2.3 mm to 14 mm depending on the variant selected, accommodating common shaft diameters used in hobby CNC, desktop robotics, and light industrial automation.
Typical use cases include DIY CNC router axis drives requiring a compact spur gear set, tabletop robotic arm joint reduction stages where a module 1 transmission gear keeps the assembly slim, and custom automation fixtures where a 45 steel spur gear with a specific tooth count is needed to achieve a target gear ratio without custom machining.
Machined from 45# medium-carbon steel for a solid balance of tensile strength and wear resistance in open-gear transmission applications.
Full-depth involute tooth form ensures smooth meshing with any other Mod 1 gear, simplifying gear ratio calculations and stage design.
Consistent 10 mm (0.39 in) face width across the range makes it easy to align multiple gears in the same plane without shimming.
A single product line covers 8 to 200 teeth, letting you source both the pinion and the wheel for a wide range of reduction ratios from one listing.
Bore options from 2.3 mm to 14 mm accommodate common shaft diameters used in hobby CNC, robotics, and light automation without additional boring.
Arrives machined to final dimensions — mount directly onto your shaft with a set screw or key (shaft hardware sold separately) and start transmitting torque immediately.
| Gear Module | 1 (Mod 1) |
|---|---|
| Tooth Profile | Standard involute, full-depth |
| Material | 45# medium-carbon steel |
| Face Width (Thickness) | 10 mm (0.39 in) |
| Number of Teeth | 8 – 200 (see variant options) |
| Bore Diameter | 2.3 mm / 6 mm / 8 mm / 10 mm / 12 mm / 14 mm (see variant options) |
| Pitch Diameter | = Number of Teeth × 1 mm (e.g., 20T → 20 mm PD) |
| Pressure Angle | 20° |
| Finish | See variant options |
| Quantity per Order | 1 PCS |
| Suitable Load | Light to medium duty open-gear drives |
Divide the driven gear tooth count by the driving gear tooth count to get the reduction ratio. For example, pairing a 20-tooth pinion with a 60-tooth wheel gives a 3:1 reduction. Browse the tooth-count options in the variant selector and pick the combination that matches your target ratio. Both gears must be Module 1 to mesh correctly.
Choose the bore diameter that matches your shaft diameter. Available bores are 2.3 mm, 6 mm, 8 mm, 10 mm, 12 mm, and 14 mm. If your shaft is metric and falls between these sizes, you may need to ream the bore to the exact dimension — a common practice in precision motion-control builds. Check the "Gear Bore & Amount" option before adding to cart.
Yes. Any two gears of the same module and pressure angle will mesh correctly regardless of tooth count. These gears use the standard Module 1, 20° pressure angle involute profile, so they are compatible with other Mod 1 spur gears from any manufacturer that follows the same standard.
45# carbon steel has a typical tensile strength of approximately 600–800 MPa in the normalized condition, making it suitable for light-to-medium duty open-gear drives such as CNC router axes, robotic joints, and automation fixtures running at moderate speeds and loads. For high-speed enclosed gearboxes or heavy shock loads, consider gears made from alloy steel or with surface hardening treatment.
45# carbon steel has limited inherent corrosion resistance. For indoor dry environments — typical of CNC machines and desktop robots — the bare steel surface is generally adequate with periodic light oiling. For humid or outdoor environments, apply a rust-inhibiting grease or consider a zinc-plated or stainless alternative for your application.
These spur gears are designed for open-gear, light-to-medium duty drives. For high-speed applications (typically above 1,000–1,500 RPM at this module), ensure adequate lubrication, check for dynamic balance on larger tooth-count variants, and verify that the bore-to-shaft fit is within acceptable tolerances to minimize vibration and noise.
For a Module 1 gear, the outer diameter (addendum circle) equals the number of teeth plus 2, multiplied by the module: OD = (T + 2) × 1 mm. For example, a 30-tooth gear has an OD of 32 mm. Use this formula to verify the gear fits within your housing or frame before ordering.
