Way (machine tool element)

A way (sometimes known as a slideway, guideway, or bedway) is a type of linear bearing, specifically a linear plain bearing, in a machine tool. It facilitates precise linear motion along a given axis. A way is ground, scraped, or (less often) molded to be very flat, and ways often come in pairs to ensure a flat plane for the carriage or sliding element (slide) to move along smoothly. Ways are usually lubricated with way oil (a kind of machine oil specially made to adhere to the ways while vertical).^[1]

Ways have been used since the 19th century and are a critical part of manufacturing processes, especially those requiring low tolerances such as machining. They have been made of various materials over the years, ranging from wood to cast iron, and nowadays including plastic alloys and special polymer materials. They are crafted with painstaking precision, usually being scraped into near total flatness with hand tools. This flatness is required to both provide good results in the manufactured parts, as well as prevent the stick-slip phenomenon (jerking motion due to friction at low speeds). In recent years they have started to be phased out by roller-element bearings ("ball" bearings), or are forgone entirely in some CNC machines.^[1]