CNC Milling Machine as a Lathe
Bertho Boman


I needed a lathe to make small accurate identical parts so the obvious answer was to use a CNC lathe. I have several manual lathes that could have been converted to CNC, and I previously built a custom CNC lathe (there is a link below), but this time there were more complex tooling steps required so I decided to use my small custom CNC mill as a lathe.

The mill is using a Taig spindle, a Consew brushless motor with speed control, PoKeys CNC57 motion controller, and Mach4 operating software. It is on my To-Do list to write up a description of it.

Lathe vs. Milling Machine:
The basic difference between a lathe and a milling machine is that the lathe has a rotating work piece and a "stationary" tool vs. the milling machine with a rotating tool and a "stationary" work piece.

Shaft Shaft
Cone Cone

Typical Parts Made

A lathe without a tool changer is limited to a single tool per operation plus maybe a rear cutoff tool. Using the mill there can be multiple tools at different fixed locations on the milling table. The desired tool is selected by moving the table to the tool location and then performing the desired operation.


Typical Tool Setup

The front left red tool is a regular lathe bit. Behind it is a cutoff tool, on the front right is a drill bit and in the center right side a "V"-tool bit. There is space for several more tools on the milling table.

Writing the G-code is an interesting challenge since there are extra tools to keep track of and the cutting directions can vary depending on the tool position relative to the spindle. All the G-code was hand-written. The speed and feeds have not been optimized in the video.

A video of the machine can be seen on Youtube:

Youtube Video

Previously a custom CNC lathe was built for a specific application also using the Taig spindle. That project can be seen here:


Hopefully this will inspire some people to try using a mill as a substitute for a lathe. There are obvious limitations but also additional features are available. For example, at the end of the lathe operation, the part can be locked into a holder and a milling bit used for regular milling operation.

Bertho Boman
Vinland Corporation
Fort Lauderdale
Florida USA
(954) 475-9093
Email: Boman33 at Vinland dot com