Turning is a machining process in which the part, held in a chuck or guided in the spindle, rotates on its own axis while a cutting tool, carried on a turret, advances to remove material. It produces parts of revolution: cylinders, cones, grooves, flat faces, bores and threads.
A standard CNC lathe drives two axes: X for diameter and Z for length. Lathes fitted with a C axis and driven tools can also mill and drill off-centre, and multi-tasking machines with a sub-spindle automatically pick up the second face of the part, which avoids a second set-up. The material arrives either as cut-off pieces or as bar fed through the spindle by a bar feeder. Tools are generally interchangeable carbide inserts, supplemented by grooving and parting-off tools and boring bars. Typical operations are straight turning (the outer cylindrical surface), facing, drilling, boring and threading.
Turning is used for anything round: shafts, pins, bushes, sleeves, pulleys, hydraulic fittings, cylinder components, special screws. For a non-cylindrical part, milling is preferred. For very large quantities of small parts, bar turning (Swiss-type machining) becomes more economical: the guide on bar turning or CNC turning helps you choose. Turned parts are ordered under the CNC machining capability.
In a quote request. Give the maximum diameter and length, the material and its delivery condition (bar or blank), the quantity and the tolerances on the diameters. For fits, state the concentricity or run-out between the different diameters: a tight coaxiality requirement means everything must be machined in the same clamping. Specify threads with their full designation, and the roughness of bearing surfaces.