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When a stripped or undersized gear brings your RC car, CNC router, or robotics project to a halt, finding a replacement that matches your exact bore and tooth count is critical. This 1 Mod Pinion Spur Gear is designed for hobbyists, makers, and engineers who need a reliable, drop-in drive gear without custom machining.
Each 1 mod pinion gear is machined from 45# medium-carbon steel and secured with a set screw for a firm shaft grip. Available in three tooth counts — 10T, 12T, and 14T — with outer diameters of 12mm (~0.47"), 14mm (~0.55"), and 16mm (~0.63") respectively. Bore options span 4mm, 5mm, 6mm, 6.35mm (1/4"), and 7mm to accommodate a wide range of motor and shaft sizes.
Typical applications include 1:10 scale RC car drivetrain upgrades, stepper motor pinion replacement in desktop CNC machines, and gear-reduction stages in DIY robotic arms. The 1 mod tooth profile also makes these gears a direct match for standard 1 mod rack-and-pinion linear motion systems.
| Module | 1 Mod (Module 1) |
|---|---|
| Tooth Count (T) | 10T / 12T / 14T (see variant options) |
| Outer Diameter | 12mm (~0.47") / 14mm (~0.55") / 16mm (~0.63") — see variant options |
| Bore Diameter | 4mm / 5mm / 6mm / 6.35mm / 7mm — see variant options |
| Material | 45# Medium-Carbon Steel |
| Shaft Locking | Set Screw (included) |
| Tooth Profile | Standard Involute, Module 1 |
| Pressure Angle | Typically 20° |
| Thickness | See variant options |
| Finish | Natural steel (uncoated) |
| Quantity per Order | 1 piece |
Tooth count determines your gear ratio. A 10T pinion paired with a larger spur gear gives higher speed and lower torque — ideal for fast RC cars. A 14T pinion produces more torque and lower top speed, better suited for rock crawlers or CNC feed drives. Match your tooth count to the mating gear's tooth count and your desired ratio.
Measure your motor shaft diameter with calipers before ordering. Common sizes: 4mm and 5mm are typical for small hobby motors; 6mm and 6.35mm (1/4") are standard for mid-size brushless motors; 7mm suits larger brushed motors. The set screw allows a small amount of adjustment, but the bore should match your shaft as closely as possible for concentricity.
45# steel (equivalent to SAE 1045) has a tensile strength of approximately 600–700 MPa, making it suitable for moderate-to-high torque hobby and light industrial applications. For extreme shock loads or continuous industrial duty, consider heat-treated or alloy steel gears. For RC cars, CNC routers, and robotics, 45# steel is a well-proven choice.
45# steel is not stainless and will oxidize if exposed to moisture without protection. For indoor CNC or robotics use, a light coat of machine oil is sufficient. For RC applications in wet or muddy conditions, apply a thin layer of grease to the gear mesh and wipe down after use. The natural steel finish can also be treated with a rust-inhibiting spray if long-term outdoor exposure is expected.
Yes. Steel pinions are commonly paired with nylon or acetal (Delrin) spur gears in RC drivetrains to reduce noise and absorb shock. The steel pinion wears more slowly than the plastic gear, which acts as a sacrificial component — a deliberate design choice that protects the motor and drivetrain from damage.
The model designation refers to the tooth count of the pinion gear: 1-10T has 10 teeth (12mm OD), 1-12T has 12 teeth (14mm OD), and 1-14T has 14 teeth (16mm OD). All three share the same Module 1 tooth profile and are interchangeable within a Mod 1 gear system — only the ratio and physical size differ.
Yes, provided your rack is also Module 1. These pinion gears mesh directly with any standard Mod 1 rack. The 10T–14T range is commonly used in compact linear actuators, pen plotters, and small CNC gantry systems where precise, repeatable motion is required.
