Rack and pinion

A round pinion meshing a straight rack — rotary to linear.

A rack and pinion converts rotation to straight-line motion (and back): a round pinion rolls along a straight toothed rack — the drive used for 3D-printer axes, steering, and sliding doors. The two share a module so they mesh, and the pinion is dropped onto the rack’s pitch line and phased so a tooth sits in a rack gap. Both are separate editable bodies.

1. Open the Generate panel from the left sidebar and choose Rack & pinion (under Gears & drives).
2. The rack and pinion drop in meshed as separate parts. The parameters open in the Properties panel, where you set them.
3. Set the shared module and pressure angle.
4. Set the pinion tooth count, the rack length in teeth, thickness, rack back depth, and bore.