7 Things You Should Know About Swiss-Style Turning Machines

Swiss watch movements have long been regarded as the benchmark for precision craftsmanship, accurate timekeeping and reliability. Even in this digital age, marque Swiss watches command premium prices and are coveted by their owners as symbols of success.

Making these watch components to strict tolerances requires highly accurate cutting machines. Not satisfied with existing technology, Swiss machine tool builders invented the Swiss-style lathe to accommodate their needs. Today, Swiss turning centers also make high-precision, high-volume parts for medical products, dental implants, aerospace and aviation, measuring instruments and many other applications.

Should you consider adding a Swiss-style turning machine to your shop? If you want to enable long production runs of high-precision parts, especially those with small diameters, then a Swiss-Style machine may be a good investment. Like all buying decisions, the more you know about how Swiss-Style turning machines work and how they are built, the better equipped you’ll be to make an informed choice. Here are 7 things you should know about Swiss-Style machines:

1. The primary point of difference between traditional turning machines and Swiss-style is that the former has a fixed headstock that holds the spinning workpiece as a cutting tool moves across to machine the OD. A Swiss-style machine, on the other hand, employs a sliding headstock that feeds bar stock through a guide bushing in the Z-axis past the stationary cutting tool. This configuration means that the cutting tool always engages the bar stock close to the bushing, thus providing the greatest degree of support and, consequently, reducing vibration and tool deflection. As a result, a well-designed and built Swiss-style lathe holds even long, slender workpieces to tighter tolerances and enables hard turning when applicable.

2. Some Swiss-Style turning machines include a sub-spindle for additional machining operations such as drilling and boring. This versatility eliminates the need to move the part from one machine to another, thus reducing overall production time, labor cost, operator error, and idle spindle time.

3. The guide bushing and spindle are at the heart of a Swiss-Style lathe’s ability to hold tight tolerances. Because the spindle is hollow, it’s critically important that the spindle material provides the optimum degree of rigidity. For example, Swiss-Style machine builder Nomura uses SCM415 chrome-molybdenum steel for its spindles. After precise machining, the outside of the spindle is heat-treated for durability, while the inside is conditioned to a different degree of hardness. This proprietary process enables the spindle to maintain greater strength, precision and stability.

4. Although Swiss-Style turning machines by design provide a more stable cutting environment, bar stock is seldom perfectly straight or round and can set up vibrations that impact precision and tool wear. Swiss-Style lathes that don’t rely on a belt drive typically create less vibration and are, therefore, more stable and precise. The sliding headstock must also move smoothly and accurately. Incorporating a linear guide with preloaded roller pads helps achieve this precise motion while the sliding mechanism absorbs much of the harmonic vibration generated by high-speed rotation of the bar stock.


Example of a fully integrated spindle that does not require a belt drive.

5. The guiding surfaces of a Swiss-Style machine should be as smooth and flat as possible to enhance stability and further reduce the effects of vibration. As capable as power-scraping devices may be, nothing matches the precision of hand-scraping by an expert craftsman. A hand-scraped machine surface can provide an ultra-precise surface with sub-micron unevenness of less than 0.0001mm.

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Hand scraping provides exceptional flatness and smoothness.

6. Other details to look for are larger-than-average, heavy-duty ball screws in each axis to more efficiently convey power from the motor to the headstock, tool holders guided by dovetailed slides that move on a thin film of oil, and the use of structurally stable materials, such as cast iron, for key components. Because these types of ball screws and slides reduce the effects of inertia, the machines will last longer and require less maintenance, thus enhancing your ROI.

7. To optimize the productivity of your Swiss-Style machines, the right automatic bar feeder can enable continuous, unattended and even lights-out operation. They also provide additional material support to further reduce vibrations and protect operators from exposed bar stock rotating at high speeds.

Easily accessible technical service, replacement parts, training and ongoing customer support are also critical considerations when choosing a Swiss-style turning machine. Working with the right supplier can reduce your true cost of ownership and provide the greatest ROI.

Want to learn more? The Swiss-style machining experts at NomuraSwiss can answer all of your questions, provide applications assistance and help you find a machine that is a perfect fit.