Many machining processes rely solely on rotational movement. This project by MakersEase presents a departure from that traditional approach, synchronizing the lathe axis motion directly with the spindle rotation. Instead of relying on standard chuck adjustments, the maker achieves complex geometries like a square profile combined with a circular center feature on a simple round metal bar. This technique is presented as an almost practical application, suggesting it might allow for centering stock without needing to adjust the main chuck, though this comes with speed limitations.
The setup utilizes a small Emco lathe, despite its weak spindle. To enable the specialized turning, a high-resolution encoder is mounted on the spindle, providing 20000 counts per revolution. The machine runs under LinuxCNC control, which handles the complex mathematics at the motion control level. The control system reads the spindle position from the encoder and uses that data to sync the axis movement. The spindle itself is only tasked with maintaining RPM while the control manages the shaping.
While the finished part looks successful, showing the square end and coolant, a challenge arose from the weak Emco spindle visibly slowing as soon as the square cut began. Furthermore, the maker noted that the tangle of chips produced was unexpected. It remains an open question what specific type of metal and what specific lathe model was used to achieve this result!
Project by MakersEase. Watch it on their YouTube channel: