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When a slipping or undersized gear causes your drive system to lose torque or skip under load, the fix starts with the right pinion. This Mod 1 steel spur gear with 15 teeth is engineered for hobbyists, makers, and engineers who need a dependable transmission component for RC vehicles, CNC builds, robotics platforms, and custom mechanical assemblies.
Each gear is machined from carbon steel and features a Module 1 (Mod 1) tooth profile — the most widely used metric gear standard. The bore diameter ranges from 4 mm (0.157 in) to 8 mm (0.315 in), covering the most common motor shaft sizes. A set screw is included for secure shaft fixation without additional hardware. Gear outer diameter is typically 17 mm (0.67 in) based on the Mod 1 / 15T formula (OD = (T + 2) × Module).
Typical use cases include: replacing worn pinion gears in 1:10 scale RC cars and trucks, building compact Mod 1 spur gear transmission pinion assemblies for CNC axis drives, and integrating into robotics joint actuators where a standardized metric gear pitch is required for meshing with Mod 1 rack-and-pinion or larger spur gears.
| Module (Pitch) | Mod 1 (1 mm/tooth) |
|---|---|
| Number of Teeth | 15T |
| Outer Diameter | Approx. 17 mm (0.67 in) |
| Bore Diameter | 4 / 5 / 6 / 6.35 / 7 / 8 mm (see variant options) |
| Gear Width (Face Width) | See variant options |
| Material | Carbon Steel |
| Finish / Coating | See variant options |
| Pressure Angle | 20° |
| Shaft Fixing Method | Set screw (included) |
| Compatible Gear Module | Mod 1 only |
| Typical Application | RC vehicles, CNC drives, robotics, DIY transmissions |
| Weight | See variant options |
"Mod 1" (Module 1) is a metric gear standard where the module equals 1 mm per tooth. This gear will mesh correctly with any other Mod 1 spur gear or Mod 1 rack, regardless of tooth count, as long as the pressure angle is also 20°. It will NOT mesh with Mod 0.5, Mod 0.8, Mod 1.5, or imperial pitch gears.
Measure your motor or drive shaft diameter with a caliper. Select the bore that matches exactly — for example, choose 6.35 mm if your shaft is 1/4 inch (a common size on brushed DC motors). A bore that is too large will cause wobble even with the set screw tightened.
Yes, a set screw (grub screw) is included with each gear. You will need a hex key (Allen key) to tighten it — the exact size depends on the screw supplied, typically M2 or M2.5. We recommend applying a small amount of thread-locking compound for high-vibration applications.
The gear is machined from carbon steel, which provides good tensile strength and wear resistance for moderate-duty continuous operation. It is suitable for RC vehicle drivetrains, light CNC axis drives, and robotics joints. For very high-torque or high-RPM industrial applications, consult the load rating of your specific assembly.
Carbon steel has limited natural corrosion resistance. For outdoor or damp environments, we recommend applying a light machine oil or grease to the gear teeth and bore area. If corrosion resistance is a primary requirement, consider a stainless steel or brass gear alternative.
The gear ratio equals the number of teeth on the driven (larger) gear divided by 15. For example: pairing with a 45T gear gives a 3:1 reduction ratio, meaning the output shaft turns at one-third the speed of the input shaft with three times the torque. Use this formula to design your target drive ratio.
Yes — Mod 1 gears are commonly used in CNC machine axis drives and some extruder gear train designs. Verify that your existing driven gear is also Mod 1 and that the bore matches your stepper motor shaft (typically 5 mm for NEMA 17 motors). The 6.35 mm bore variant suits NEMA 23 motors with 1/4-inch shafts.
