CNC Turning

During the turning process, rod stock is rotated while a tool is held against the stock to remove material and create a cylindrical part. We employ a CNC lathe with live tooling so features like axial and radial holes, flats, grooves, and slots can be machined. Outside diameter (OD) and inside diameter (ID) threading is also available. Our range of metals, including soft metals and steel, allows parts to be made with the desired material properties, and good tolerances yield parts suitable for form, fit and functional testing.
1 to 200+ parts
Shipped in 1 to 3 days
Parts start at $65

Design Guidelines


  • Maximum part diameter: 2.95 in. (75mm)
  • Minimum part diameter: 0.16 in. (4mm)
  • Maximum part length: 9.0 in. (228mm)
  • Minimum part length: 0.05 in. (1.3mm)

Small features

Small features may be allowed, but the diameter in any region should not be less than 0.030 in. (0.76mm). Sharp conical points are allowed; angles should be greater than 30 degrees. Walls thinner than 0.020 in. (0.5mm) typically do not survive the machining process.


In general, tolerances of +/- 0.005 in. (0.13mm) are expected.
Holes and grooves part

Holes and grooves

Proto Labs can add on-axis, axial and radial holes to turned parts. We only support holes that are either parallel or perpendicular to the axis of revolution, and cannot accommodate holes at odd angles.
Minimum hole size:
  • On-axis and axial: 0.04 in. (1mm)
  • Radial: 0.08 in. (2mm)

  • Minimum OD groove width: 0.047 in. (1.2mm)
  • Maximum OD groove depth: 0.95 in. (24.1mm) — varies with groove width
  • ID grooves not currently supported
Radial holes and axial holes illustration

Live tooling

Proto Labs' lathe machines contain live tools that allow additional milled features to be added to turned parts including flats, slots, grooves, axial and radial holes.


Sharp inside corners on a part will be radiused (rounded) as a natural result of the live tooling machining process. Our automated quotes highlight areas where these radii will occur. Turned outside corners will typically include a 0.005 in. (0.13mm) chamfer.

Text on parts

Text is not supported on turned parts at this time.

Surface finish

Parts that are turned typically have a very smooth surface finish. The as-machined surface finish of the cylindrical areas will typically be much smoother using the lathe than the mill, so consider this when selecting the machining method for those parts that qualify for either method. Areas cut with live tooling, such as flats and slots, may have visible tools marks. If desired, the metal parts can be lightly bead blasted leaving a fine matte finish. Hard metals like steel and stainless steel can also be de-burred with a light bead blast to remove metal slivers, and sharp or rough areas.

Threaded features

Proto Labs' CNC turning supports UNC, UNF and metric sizes for internal threads, coil insert threads and external threads:
Standard internal threads: UNC and UNF threads are supported for standard holes from #4 through #8 (UNC) and #10 (UNF). Metric threads are supported from M3 through M5. Additionally, we support up to 1/4 (UNC), 1/2 (UNF) and M10 (metric) for on-axis holes.

Coil insert threads: We support coil insert threading for UNC and UNF from #2 through #8 (UNC) and #10 (UNF) and metric threads from M2.5 through M5. Additionally, we support up to 1/4 (UNC) and 1/2 (UNF) and M8 (metric) for on-axis holes.

External threads: Outer diameter on-axis threads are also available in UNC and UNF #4 to 3/4 and metric from M3.5 to M20.

Because of the lack of standards between CAD packages for specifying threads, our automated system decides where to place threads by looking for potential inner and outer diameters that are suitable. Avoid modeling threads on parts uploaded to Proto Labs. More details.


Proto Labs offers turned parts in a variety of metals. See full list of machined materials.
  • Aluminum
  • Stainless Steel
  • Steel Alloy
  • Steel Mild Low Carbon
  • Titanium