Add full 4th-axis capability to your mill with a rotary table or trunnion. Centroid supports A-axis (rotation around X) and B-axis (rotation around Y).

• True simultaneous 4-axis interpolation
• Wrapped geometry, helical cuts, cylindrical contouring, and multi-sided machining
• Precise indexing for complex 3D parts, engraving, impellers, and more

Program your rotary axis from any CAD/CAM software or use Centroid's easy Intercon conversational programming system for fast simple 4th axis work.

Centroid's G-Code Smoothing works on rotary axes! Smoothing pre-processes short-vector toolpaths to create fluid motion with reduced jerk and vibration — delivering superior surface finishes on rotary contours.

Centroid's Inverse Time feed mode (G93) gives precise control over move timing, ensuring consistent chip load and cycle time during complex 4-axis moves as well.

Upgrade your CNC lathe to a true mill-turn center with live tooling and full C-axis control.

• Continuous C-axis interpolation and positioning
• Polar and cylindrical interpolation for off-center milling, drilling, tapping, and keyway cutting
• Polygon turning and complex face/diameter contouring without removing the part

Create programs in CAD/CAM or with Intercon conversational. G-Code Smoothing and Inverse Time mode further enhance motion quality and timing precision on C-axis operations.

• Automated Rotary Setup — Multi-point probing automatically calculates true center and diameter. The axis rotates 180° to cancel runout for high accuracy on any workpiece size.
• High-resolution closed-loop control with direct-drive encoders (~0.01 mm precision).
• Fast, repeatable probe cycles for quick alignment.
• Seamless synchronization of linear and rotary axes.

4th Axis Engraving a Scale with Acorn DIY CNC

Watch a complete workflow demonstration of 4th axis engraving on a rotary table using a Centroid Acorn DIY CNC mill. Uwe Mattern shows the full process of creating precise engraved scales on a cylindrical workpiece with simultaneous 4-axis toolpaths. This practical example highlights how easily Centroid controls handle wrapped geometry and rotary engraving — perfect for scales, dials, or decorative cylindrical parts

Vertex HV6 CNC 4th Axis

Watch the first steps in building a DIY CNC 4th axis using a Vertex HV6 rotary table on a mill controlled by Centroid CNC. Uwe Mattern demonstrates the initial mechanical setup, including mounting the stepper motor, worm gear coupler, and aluminum components to create a functional rotary axis. This practical build video shows how straightforward it is to add 4th-axis capability to your Centroid-controlled milling machine.

C-Axis milling on a hobby lathe with Acorn DIY CNC

Watch a practical demonstration of C-axis milling on a hobby CNC lathe controlled by Centroid Acorn. Uwe Mattern shows how to quickly add live tooling capability by fabricating a simple bracket to mount a more powerful router, then performs real C-axis milling operations on the lathe. This video highlights how straightforward and fast it is to enable productive C-axis work — even on a small hobby lathe.

Acorn DIY CNC Lathe with C-Axis Polyform Milling

Watch C-axis polyform milling in action on a DIY CNC lathe controlled by Centroid Acorn. Uwe Mattern demonstrates machining an excenter (eccentric shape) using coordinated C-axis rotation and live tooling. The video shows the full process, including toolpath generation in a spreadsheet (LibreCalc) and G-code modifications for roughing passes — all performed with a single grooving tool.A great example of advanced C-axis capabilities, turning a simple lathe into a versatile machine for complex off-center and polygonal milling.

Adaptive Mill Turning with Acorn6 on a DIY CNC Lathe with C-Axis

Uwe Mattern demonstrates machining a part with coordinated C-axis rotation and live tooling, while developing and testing a custom post processor for Fusion 360. The video covers G-code handling, tolerance adjustments, G-code smoothing, and multiple light passes to achieve excellent surface finish on complex C-axis operations.A practical example of advanced CAD/CAM integration and high-quality C-axis milling on a hobby-level lathe.

C-Axis Broaching with a Acorn DIY CNC Lathe

Watch C-axis broaching (keyway cutting) on a hobby CNC lathe controlled by Centroid Acorn. Uwe Mattern demonstrates a flexible G-code program that performs internal or external broaching of single or multiple keyways/grooves using live tooling and coordinated C-axis rotation. The program requires only a few parameters and automatically handles different starting and ending diameters.A practical example of how Centroid's C-axis capabilities turn a simple hobby lathe into a versatile machine for precise grooving and keyway work.

4th axis setup

• Automatic Workpiece Centering: Probes 3 points on the workpiece to calculate the diameter and find the true center.
• Runout Compensation: Rotates the axis 180° while probing both sides of the part to cancel out any runout for much higher precision.
• No Manual Adjustments: Everything is automatic — no manual adjustments needed for different diameters.
• Upgraded Precision: Uwe also mentions upgrading the rotary table with a direct-driven encoder for closed-loop control, which eliminates backlash and stick-slip. This gives roughly 0.01 mm precision at the outer diameter.