Design Guidelines: CNC Turning

Our basic guidelines for CNC turning include important design considerations to help improve part manufacturability, enhance cosmetic appearance, and reduce overall production time.


Maximum Dimensions

Diameter 2.95 in.
Length 9 in.
Diameter 74.03mm
Length 228.6mm

Minimum Dimensions

Diameter 0.16 in.
Length 0.25 in. to 0.030 in
Wall Thickness 0.020 in.
Angle 30°
Diameter 4.064mm

6.35mm to 0.762mm 

Wall Thickness




Typically, Proto Labs can maintain a machining tolerance of +/- 0.005 in. (0.127mm).

applications engineer analyzing CAD model

Design Feedback
For additional questions, please contact an applications engineer at or 877.479.3680.

Live Tooling Capabilities

Our lathe machines contain live tools that allow additional milled features to be added to turned parts including flats, slots, and grooves. We can also add on-axis, axial, and radial holes to turned parts, but only support holes that are either parallel or perpendicular to the axis of revolution, and we cannot accommodate holes at odd angles.

cnc turning capabilities include radial and axial holes


  • Aluminum
  • Brass
  • Low Carbon Steel
  • Steel Alloy
  • Stainless Steel
  • Titanium


a lathe machines metal rod stock into a final part

Surface Finishes

Soft metals like aluminum and brass 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 which removes metal slivers and sharp or particularly rough areas.


PLASTIC As-machined
METAL As-machined, deburred, or deburred with a light bread blast

Threaded Holes

We currently support UNC and UNF threads from #2 up to 0.5 in., and metric threads from M2 to M12. Avoid modeling internal threads on your part design.




Sharp inside corners on a part will be radiused (rounded) as a natural result of the CNC machining process. Resulting radii will be identified before the part is milled. Turned outside corners will typically include a 0.005 in. chamfer.



team of applications engineers

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