Mod 1 Steel Pinion Gear Spur Gears 12-30 Teeth 6-15mm Bore With Screw Hardened

The gear ratio between two meshing Mod 1 spur gears equals the ratio of their tooth counts. For example, pairing a 12-tooth pinion with a 24-tooth gear gives a 2:1 reduction. Choose a smaller tooth count (12–16 T) for higher speed output and a larger count (24–30 T) when you need more torque at lower RPM. Always verify center distance: for Mod 1 gears, center distance = (T1 + T2) / 2 mm.

Match the bore to your motor or shaft diameter exactly. Common DC hobby motors use 3 mm, 4 mm, 5 mm, or 6 mm shafts; NEMA 17 stepper motors typically use a 5 mm shaft; larger servo or gearbox outputs often use 6 mm, 8 mm, or 10 mm shafts. The 6.35 mm (1/4 in) bore suits imperial-standard shafts. If your shaft is 14 mm and requires a key, select the 14 mm + Keyway 5 mm variant.

The gears are machined from carbon steel with surface hardening, giving them significantly higher fatigue strength than brass or plastic alternatives. Exact load ratings depend on operating speed, lubrication, and duty cycle. For continuous high-torque applications, we recommend applying a light gear grease and ensuring proper shaft alignment to maximize service life.

Hardened carbon steel offers good mechanical strength but has limited inherent corrosion resistance. For indoor robotics, CNC, and dry environments these gears perform reliably without additional treatment. In humid or outdoor environments, apply a thin film of anti-rust grease or consider periodic re-lubrication to prevent surface oxidation.

Yes — any Mod 1 spur gear meshes with any other Mod 1 spur gear of the same pressure angle (20°), regardless of tooth count. These gears are not compatible with Mod 0.5, Mod 0.8, Mod 1.5, or DP-standard gears. If you are unsure of your existing gear's module, measure the outer diameter in mm and divide by (tooth count + 2); a result close to 1.0 confirms Mod 1.

Both options ship the same gear in the same specification. Selecting 2 PCS means you receive two identical gears in one order — useful when building a matched pinion pair, replacing both gears in a drive stage simultaneously, or keeping a spare on hand. The per-unit price is slightly lower on the 2 PCS option for most configurations.

The radial set screw uses a standard hex (Allen) socket head. A metric hex key in the appropriate size (typically 1.5 mm – 3 mm depending on the screw size) is required. Tighten the set screw firmly against a flat on the shaft where possible to prevent rotation under load.