STAR sliding headstock lathes: the excellence of precision CNC turning

A legacy of innovation: STAR from watchmaking to global industry

STAR (Star Micronics) is a Japanese machine tool manufacturer founded more than seven decades ago. The company started out in the 1950s producing watch and camera parts. To meet its own precision requirements, STAR then developed its first automatic lathe in order to machine watch components in-house. This pioneering choice – ‘machines created by users for users’ – laid the foundations for a long history of innovation. From 1962, STAR began exporting its sliding headstock lathes to Europe, enjoying immediate success thanks to the quality of its products and their originality.

Over the decades, STAR has established itself as a major player in the sliding headstock CNC lathe industry (also known as the ‘Swiss’ automatic lathe). Historically designed for watchmaking, this Swiss technology makes it possible to machine small parts with great precision. STAR has perfected the concept: increased rigidity, optimised automation and reliable CNC (Fanuc numerical controls are very widespread) have enabled its machines to conquer new sectors. Today, the brand has a global network (factories in Japan, China and Thailand, subsidiaries in Europe and the USA) and its machines serve a variety of industries - from medical to aerospace - all over the world. STAR's reputation is based on its ability to supply robust, high-precision machines that meet the needs of the most demanding industrial users.

 

Cutting-edge applications in multiple industrial sectors

STAR sliding headstock lathes are popular in many fields where precision and repeatability are essential. Here are some typical application sectors for STAR machines, with examples of parts produced on these automatic CNC lathes:

 

Medical & Dental: manufacturing of precise medical parts in special alloys. For example, osteosynthesis screws (bone screws), dental implants, prosthesis components (hinges, rods) or miniature surgical instruments are machined on STAR lathes. These parts, often made of titanium or stainless steel, require a flawless finish and tight tolerances to ensure biocompatibility and reliability – a result that CNC sliding headstock turning achieves in a single operation.

 

Watchmaking & Micromechanics: a traditional sector for sliding headstock lathes, luxury watchmaking requires the machining of tiny components with extreme precision. STAR automatic lathes produce watch arbors, tiny screws, pinions and complexly shaped watch parts (such as tourbillon cages or barrels) with a guaranteed flawless surface finish. Similarly, precision micromechanics (measuring instruments, miniature connectors) benefit from the ability of STAR machines to produce identical series with almost perfect dimensional control. In this field, STAR lathes sometimes compete with processes such as electrical discharge machining to produce complex shapes, while offering the productivity of mass production turning.

 

Electronics & Connectors: the manufacture of high-precision electronic connectors and connector components in brass, copper or special alloys is another ideal playing field for STAR lathes. Lugs, pins, contacts, adjusting screws, sensor axes... all these small components are machined in large quantities. For example, a coaxial connector or a precision plug has turned components with grooves, transverse holes for pins, etc. The automatic CNC lathes with sliding headstocks produce these complex geometries (multiple radial drillings, threading, trimming) without repositioning, ensuring perfect final assembly of the electronic components.

 

Automotive & Aeronautics: in the automotive and aerospace industries, many small components require reliable mass production. STAR lathes are used, for example, in the machining of fuel injectors (a part with very fine calibrated holes), hydraulic or pneumatic connectors, valve pins, special engine screws and parts of aeronautical fittings. A concrete example is the production of high-pressure steel connectors for ABS braking systems: these complex parts, which are tapped, deep-drilled and equipped with sealed bearing surfaces, can be produced on a STAR 32 mm lathe in a single multi-tool pass. Similarly, in aerospace, small critical parts such as bushings, spacers or light alloy fasteners are entrusted to sliding headstock STAR lathes to guarantee consistent precision in large production runs. STAR's manufacturing quality ensures the reliability that is essential in these sectors.

 

Other sectors (optics, agriculture, luxury): thanks to their versatility, STAR machines are also used in optics (spectacle frames machined from brass or titanium), the luxury sector (prestige pens, mechanical jewellery components) and the manufacture of electrical tools and components for industrial machinery. Wherever it is necessary to machine parts of revolution or prismatic parts with precision from a few millimetres to a few centimetres, STAR sliding headstock lathes provide an effective solution. They offer an excellent balance between productivity (fast automated cycles) and precision (repeatability for batches of thousands of units), which explains their adoption in a wide variety of fields.

 

STAR SR range: automatic CNC lathes for every need

The STAR SR series includes iconic automatic CNC lathes with sliding headstocks, available in several models to cover different machining diameters and varying levels of complexity. The SR-32 (32 mm) and SR-20 (20 mm) models are among the most popular. They share the common STAR DNA – rigid dovetails, high precision, high productivity and reliability – while having their own technical specificities.

 

STAR SR-32 – Versatile and robust 32 mm lathe

The STAR SR-32 is a sliding headstock lathe capable of machining bars up to Ø 32 mm. It is one of the brand's historic models, recognised for its robustness and versatility. Designed for high-precision parts of medium diameter, it already offers the advantages of the ‘sliding headstock’ concept. The original SR-32 has a high-speed main spindle (approx. 8,000–10,000 rpm) and a sub-spindle to pick up the workpiece and machine its reverse side, thus producing the complete workpiece in a single pass.

 

 

STAR SR-32J and its Type N version – Technological evolution and flexibility without a guide bush

The STAR SR-32J represents the new generation of the SR-32. Visually and technically, it retains the compact format of a 32 mm sliding head lathe while incorporating notable improvements. STAR has reinforced the rigidity of the machine via an inclined bed structure (prismatic dovetail guide) to absorb vibrations during demanding machining operations. The power output of the motors has been increased, both for the main spindle and for the motorised tools, in order to machine difficult materials or larger diameters efficiently. The SR-32J also stands out for its improved rapid traverse speed of the axes (over 20 m/min), reducing downtime between tool passes and increasing productivity.

 

The Type N version of the SR-32J eliminates the guide bush and operates in so-called ‘tailstock without guide’ mode: the bar is no longer supported just before the tool, which limits the machinable length per pass (in practice, about 2.5 times the diameter, i.e. ~80 mm max for Ø 32). On the other hand, this reduces the waste at the end of the bar to just a few centimetres, optimising the material used. The SR-32J Type N therefore excels in the production of short and relatively large diameter components, with a significant economic gain on the raw material. Conversion between mode with or without guide bush can be done via adaptations, offering maximum flexibility depending on the type of production (long revolutions or small prismatic components).

 

 

STAR SR-20R – Precision on small bars and mass production

The STAR SR-20R is a sliding headstock lathe designed for bars with a maximum Ø 20 mm. This smaller diameter makes it suitable for machining very high-precision components, often with finer or lighter dimensions. Historically, the SR-20R has been one of STAR's best sellers for industries requiring large-scale production of small-sized components (connectors, watchmaking, instrumentation, etc.). Thanks to its sliding headstock technology, it excels in the machining of long, thin components such as axles, screws, spindles and pins, without flexing or vibrating, ensuring an excellent finish.

 

 

STAR SR-20RII – Improvements in productivity and machining capacity

In the wake of the success of the SR-20R, STAR has introduced the SR-20RII, an improved version that builds on the proven foundations of the initial model, adding technical refinements. Externally similar, this second-generation 20 mm sliding headstock lathe incorporates a more recent Fanuc CNC and reinforced motorisations. The SR-20RII is characterised by increased power of the main spindle (more than 3 kW at peak) and optimised axes to support even more complex machining. The total number of tools that can be accommodated has been increased, with, for example, the addition of additional transverse motorised tools. Where the SR-20R had, for example, 4 rotating tools, the SR-20RII can accommodate up to 8 or 10 motorised tools (depending on the configuration) in addition to those intended for conventional turning. This broadens the range of operations that can be carried out in a single pass: milling of complex shapes, multiple lateral drilling, simultaneous machining on several axes, etc.

With the SR-20RII, STAR has also improved ergonomic design and automation: optimised chip removal and cooling for long uninterrupted cycles, a mobile control panel for easy access during adjustments, and quick tool change devices to reduce set-up times. Repeatability and precision remain the strong points, thanks to a rigid monobloc construction that maintains axis alignment. In production, the SR-20RII allows optimal results to be achieved even on a complex product, all with increased productivity compared to the first generation. Industrial users particularly appreciate the SR-20RII's ability to produce in a single operation components that previously required several stages. This translates into time savings, reliability (no repositioning errors) and consistent quality from the first to the last part of a series.

 

New or used purchase: access STAR performance according to your budget

Should you turn to the second-hand market for a proven model? Here are some points to consider for anyone considering purchasing a STAR lathe:

 

Buying a second-hand STAR lathe:

The second-hand market for this type of machine tool is very dynamic. Many workshops are renewing their equipment and reselling older models of STAR lathes that are still in excellent working order. This allows for a much faster return on investment, especially for SMEs looking to increase capacity. On the other hand, availability is almost immediate: as the tower has already been built, it only needs to be delivered and installed, which takes a few weeks at most, whereas a new model could be delivered the following year. For a company with an urgent production need or a contract to be fulfilled quickly, the quick access offered by the opportunity is a major advantage.

 

Reliability and performance are guaranteed:

STAR lathes are renowned for their durability, and a well-maintained second-hand model can still offer optimum performance for many years. Machines built in the 2000s, such as the SR-20RII or SR-32J, generally retain all their precision after recalibration. It is not uncommon to see older generation STAR CNC automatic lathes running 24 hours a day in workshops without a hitch. In addition, standardisation around the Fanuc CNC facilitates maintenance or restarting: spare components (cards, drives, etc.) remain available and many technicians know how to work on these conventional numerical controls. By choosing a dealer in second-hand machine tools, the buyer can obtain a fully overhauled machine, restored to operational condition according to the manufacturer's standards.

 

In conclusion, the second-hand market for STAR sliding headstock lathes offers an interesting opportunity to equip yourself with a high-performance machine. For most common industrial applications (precision bar turning in the medical, watchmaking and connector industries, etc.), a well-chosen second-hand STAR model will enable you to achieve optimal results in machining while maximising the profitability of your investment. The key is to assess your technical needs and production requirements: the STAR brand, with its wide range of reliable and proven models, offers solutions for every scenario, from the small workshop looking for a versatile automatic lathe, to the high-tech factory wanting the ultimate in CNC sliding headstock. In all cases, integrating a STAR lathe into your production flow means choosing quality, precision and productivity – decisive assets for remaining competitive in today's demanding markets.