“Precision Starts at the Micron Level” – Advantages and Applications of NSK Super Precision Bearings

While standard rolling bearings already offer high levels of precision when installed correctly, certain applications, such as those in the machine tool industry, demand even greater accuracy. These environments also subject bearings to high rotational speeds and significant loads. To meet these challenges, several leading manufacturers offer specialized Super Precision bearings, often referred to as spindle bearings.

We spoke with Jörg Wagner from NSK about what sets these precision bearings apart, how they differ from standard bearing types, and what trends are shaping the future of Super Precision bearing technology.

Mr. Wagner, could you briefly introduce yourself and the company NSK?

Jörg Wagner: My name is Jörg Wagner, and I’m the Sector Manager for Machine Tools at NSK. I’m responsible for driving our machine tool business in Europe, with a focus on linear motion and Super Precision bearings. NSK is a Japanese company with over 100 years of history. The name stands for “Nippon Seiko KK,” which translates to “Japanese Precision Components.” We are one of the world’s leading manufacturers in both rolling bearings and linear motion technology.

What exactly defines a Super Precision bearing, and how does it differ from a standard bearing or NSK’s HPS bearings?

Jörg Wagner: As the name suggests, Super Precision bearings are manufactured with extremely tight tolerances and outstanding accuracy in terms of runout and dimensional stability – down to a few microns. This level of precision is essential to meet the performance demands of today’s machine tools, particularly when tight machining tolerances and high rotational speeds are involved.

Standard bearings are designed for less demanding environments. Our HPS (High Performance Standard) bearings represent a high-end standard solution, offering increased load capacity, optimized internal geometry, and extended service life. They're ideal for applications like electric motors or industrial machinery, where a full Super Precision bearing might not be necessary.

Which bearing series does NSK offer in the Super Precision range, and how should customers approach their selection?

Jörg Wagner: We offer several Super Precision bearing series, each tailored to specific application needs. For example, our 70, 72, and 79 series use larger balls, making them well-suited for applications with high radial loads and moderate speeds.

For significantly higher speeds, our Robust Series is the preferred choice. These bearings use medium-sized balls and can achieve very high speed ratings – up to 3 million dm*n, which corresponds to 30,000 rpm at a 100 mm pitch circle diameter (about 80mm bore). For customers who require both high speed and high load capacity, we recommend our RobustDyna Series, which combines both characteristics through an optimized internal design. We also offer cylindrical roller bearings in single- and double-row configurations, designed for applications requiring especially high radial stiffness.

Ultimately, the ideal bearing depends on the specific demands of the application – whether speed, load, space constraints or thermal performance are the priority.

What makes NSK’s high-precision bearings stand out compared to other manufacturers?

Jörg Wagner: At NSK, maintaining consistently high manufacturing quality is a top priority. Our runout and tolerance standards strictly adhere to ISO specifications. In addition, we ensure above-average reproducibility through the use of state-of-the-art manufacturing technologies – an especially crucial factor for high-speed spindles, where even the slightest deviations can significantly impact performance.

Another differentiator is our cage technology. Our SURSAVE cage, for example, is engineered for optimal oil flow, minimal imbalance, and low thermal expansion – contributing to extremely smooth operation, even at very high speeds.

In our hybrid bearings, we combine silicon nitride ceramic rolling elements with ultra-clean, high-purity steels. This pairing significantly reduces micropitting and extends bearing life. We also offer a wide range of preload options, precisely graded and factory-marked, ideal for vibration-sensitive environments.

Our lubrication solutions are another strength: Our portfolio includes a wide range of high-performance lubricants, as well as various bearing designs for oil or grease relubrication. Of course, we also offer Super Precision Bearings with non-contact seals that enable reliable lifetime lubrication.

Notably, NSK bearings can achieve extremely high dm*n values. In some cases, these reach up to 3 million, positioning us as a leader in ultra-high-speed applications such as aerospace and high-frequency spindles.

Quality assurance is another core strength: every NSK Super Precision bearing is traceable by lot number, individually tested, and inspected for noise and vibration. This level of control sets us apart in terms of both technological expertise and process reliability.

In which industries or applications are high-precision bearings typically used?

Jörg Wagner: The primary market is the machine tool industry, especially in main spindles of milling, turning, and machining centers. Super Precision bearings are also commonly used in live tooling units and high-performance spindle modules. Beyond that, they are found in applications such as printing machinery, gearboxes, and specialty equipment – anywhere precise, repeatable movement is critical.

How does the international ISO standard differ from the Japanese JIS, the German DIN, or other well-known standards and what should customers be aware of when selecting bearings?

Jörg Wagner: The dimensional tolerances and running accuracy of NSK radial bearings comply with the specifications outlined in “Accuracies of Rolling Bearings” according to ISO 492, 199, 582, and 1132-1, as well as “Rolling Bearing Tolerances” under JIS B 1514. In addition, NSK also manufactures angular contact ball bearings in precision classes ABEC 5, 7, and 9, based on Standard 20 of the American Bearing Manufacturers Association (ABMA).

Ultimately, however, all these standards follow the same basic principles – whether it’s JIS (Japan), DIN (Germany), ISO (international), or ABEC/AFBMA (USA). While the designations may differ, the technical content is nearly identical. That means the various standards are largely interchangeable.

For example, our P2 tolerance grade under JIS aligns with DIN P2 or ABEC 9 in the U.S. Ultimately, what matters most is not the standard’s name, but an understanding of what the specific tolerance class entails in terms of performance.

What technological trends and developments do you expect in the Super Precision bearing market?

Jörg Wagner: Focusing specifically on Super Precision bearings for machine tools, I’d say the current market is experiencing a degree of uncertainty, especially with the ongoing transformation of the automotive sector. Many previously stable applications are being disrupted by the shift to electric mobility.

As a result, customers are increasingly looking for versatile bearing solutions – products that can deliver both high speeds and high load capacities. Our RobustDyna Series is designed exactly with this in mind: a universal solution that offers the best of both worlds without compromise.

Thank you for the insightful conversation, Mr. Wagner.

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