CNC turning: CNC turning is a machining process in which the workpiece spins while a cutting tool removes material, producing round parts such as shafts, pins and bushings.
On a CNC lathe, bar or a cut blank is gripped in a chuck or collet and spun. Tools on a turret cut outside diameters, faces, grooves, threads and bores. Anything rotationally symmetric suits turning, and a bar-fed lathe can make many parts in a row with little operator time.
What it means for the price
Turned parts are often cheaper than milled parts of a similar size, because setups are simple, round stock is close to the part’s shape, and cycle times are short. The cost drivers are the stock diameter and length (including an allowance for facing and parting off), cycle time, the number of operations, and any milled features that need a second machine or a mill-turn centre.
Example: a shaft 20 mm across and 80 mm long might be cut from 22 mm bar, with a few millimetres extra on the length for facing and parting off, so the material is priced on that slightly larger piece. The figures are an example.
Common confusions
A flat, a cross-hole or a keyway on a turned part is a milling operation, even when it is cut on a lathe with live tooling. Quotometry prices CNC turning today; a part that is not mostly round goes to the shop’s review with a suggestion to mill it. Read CNC milling vs turning or see the CNC turning process page.
Go deeper: CNC milling vs turning: which process for which part