Free Pinion Gear Generator | Motor Pinions & Small Driver Gears

Design custom driving pinions for stepper motors (NEMA 17, NEMA 23), DC hobby motors, and servo actuators. Customize low-tooth-count pinions with profile shift to eliminate undercutting, and add precision motor shaft D-bores, keyways, and set screw clearances.

Key Features

• Profile shift modification to prevent tooth undercutting on pinions with <17 teeth
• Custom bore diameters for standard motor shafts (3mm, 5mm, 6.35mm, 8mm)
• ANSI and DIN standard keyways for high-torque mechanical transmission
• Direct meshing compatibility with racks, spur gears, and internal ring gears
• Instant export to CAD DXF, vector SVG, and 1:1 scale printable PDF
• Free forever with local in-browser calculation speed

Frequently Asked Questions

What is undercutting in pinion gears and how do I avoid it?

Undercutting occurs when a pinion has fewer than 14 to 17 teeth and the generating tool removes material at the tooth base, weakening it. In GearDXF, apply positive profile shift (+x) to widen the base.

How do I size a pinion for a NEMA 17 stepper motor?

NEMA 17 motors commonly use a 5mm diameter shaft (often with a D-flat). Set the center bore to 5.0mm (or 5.1mm for 3D printing clearance) in the gear properties panel.

Does a smaller pinion increase torque or speed?

Driving with a smaller pinion into a larger gear reduces output speed but increases output torque proportionally to the gear ratio.