The rack and pinion is a mechanical system used to convert rotary motion into linear motion, or vice versa. In the context of a lathe, it is typically used in the carriage assembly to move the carriage along the bed. The pinion is a small gear connected to a handwheel or drive mechanism, and the rack is a straight, toothed bar mounted parallel to the bedways.
When the operator turns the handwheel, the pinion rotates and engages the teeth of the rack, causing the carriage to move smoothly along the length of the lathe. This system allows for controlled manual movement of the cutting tool during setup or machining operations. Because it provides direct mechanical linkage between the handwheel and the carriage, the rack and pinion system offers a simple, reliable means of positioning the tool with precision and repeatability.
