Mill-Turn vs Pure Milling vs Pure Turning

Mill-turn machines — machines that combine a lathe spindle with live tooling and sometimes a B-axis milling head — are getting more common. But they're not always the right answer. Here's our take after running all three types for over a decade.

Pure Turning: When It Makes Sense

Pure turning (no live tooling) is the fastest way to make cylindrical parts. If your part is a shaft, a pin, a bushing, or a ring with only turned features — diameters, chamfers, radii, threads — a dedicated 2-axis lathe is the cheapest and fastest option. Cycle times are short, setup is simple, and the machine rate is lower than a mill-turn or machining centre.

We run Mazak QT lathes for pure turning work. Typical parts: shafts up to 600mm, pins, threaded fasteners, and simple bushings. Tolerances: ±0.005mm on diameter. Surface finish: Ra 0.4µm as-turned.

Pure Milling: When You Need It

Milling is for prismatic parts — brackets, housings, plates, enclosures. Parts that don't have a dominant axis of rotation. If your part fits in a vice and needs features on multiple faces, a milling machine (3, 4, or 5-axis) is the right tool.

We run Haas VF for 3-axis, Mazak VCN for 4-axis, and DMG MORI DMU 80 for 5-axis. The choice between them depends on complexity, not cost per hour. See our axis comparison guide for details.

Mill-Turn: The Hybrid Option

A mill-turn machine (also called a multi-tasking lathe or B-axis machine) combines turning and milling in one setup. The part is held in the lathe spindle, and a milling head can access it from multiple angles. This eliminates secondary operations: you turn the OD, mill a keyway, drill a cross-hole, and thread the end — all in one program.

When does mill-turn make sense? Parts that are generally cylindrical but have milled features: hydraulic spools with cross-drilled holes, motor shafts with keyways or flats, fittings with hex features, aerospace pins with complex end geometry.

When does it NOT make sense? Simple cylindrical parts (a plain shaft) are faster and cheaper on a pure lathe. Complex prismatic parts (a bracket) are better on a machining centre. Mill-turn is for parts that sit in the middle — cylindrical enough that turning is the primary process, but with enough milled features that a second setup would cost more than the mill-turn premium.

Real Numbers: Cost Comparison

Per-part estimates at 100-piece quantity. Tooling and setup amortised.

What We Recommend

We have all three capabilities in-house. When you send us a drawing, we don't just quote it on one machine type — we look at the geometry and decide which approach makes the best part at the lowest cost. Sometimes that's a mill-turn. Sometimes it's a lathe followed by a quick milling op. Sometimes it's all on a 5-axis. The right answer depends on the part, not on what machine we're trying to keep busy.