Shaft couplings and special screws made by Nabeya Bi-Tech Kaisha

In 2003, PM started a strategic partnership with Nabeya B-tech Kaisha (NBK) from Japan. It includes the distribution and promotion of their extensive range of flexible shaft couplings and specialized screws. On this page, we give a short introduction to the NBK brand shaft couplings and special screws. They are linked to other pages with more in-depth technical information.

NBK - 450 years of craftsmanship

The rich history of NBK dates back to 1560 when Mr. Taro-Uemon-i Okamoto founded the company. It began as a metal foundry for casting pots, tea kettles, and temple bells.

In 1940 NBK was re-established in its today's form by Mr. Tomokichi Okamoto with the poduction of pulleys. Today, NBK is renowned for its pioneering designs, exceptional product quality, and remarkable delivery capabilities.

Nowadays, the main products of NBK are the miniature shaft couplings (over 100 models!) and the special screws.

To download the company profile of NBK click here.

Some facts about NBK flexible shaft couplings and special screws

Did you know about NBK couplings that:

  • they offer 130 models divided over 9 shaft coupling product groups
  • is the Japanese market leader in flexible shaft couplings

  • offers customisation of couplings and screws

  • has 99,96 on-time delivery score

Selection procedure of miniature shaft couplings

With over 9 types and over 100 models of shaft couplings, it is difficult to select the right coupling.

The selection of shaft couplings is done in 4 simple steps:

  1. Determine coupling type based on application

  2. Select a coupling material suitable for the operating environment

  3. Select a coupling size suitable for the applicable torque, space, and shaft bores

  4. Determine shaft and coupling fastening method

Determine the right shaft coupling based on the application

Miniature shaft coupling applications can be broadly divided into two distinct categories.The first category, known as "motion control," focuses on regulating the movement of a device. This involves using couplings specifically designed for servomotors or stepping motors.

The second application pertains to "power transmission", where couplings are employed in conjunction with general-purpose motors to facilitate efficient power transfer.

After selecting the appropriate shaft coupling in step 1, the subsequent three steps can be executed with relative ease. The NBK website serves as a valuable resource in this process, as it facilitates the selection procedure by enabling users to choose based on specific criteria.

Shaft couplings for "motion control"

In the past, it was recommended to use disk couplings, which had an all-metal body and offered high torsional rigidity. However, with the significant improvement in motor performance, high-gain rubber couplings are now considered the ideal choice.

High-gain couplings provide excellent vibration absorption and optimal torsional rigidity, effectively preventing system resonance and allowing for maximum motor performance.

Nevertheless, depending on the specific equipment and environment, there may still be a preference for traditional types of couplings. In such cases, we recommend slit couplings with a simple integrated structure. These couplings are suitable for applications where rigidity is important, and they offer superb precision in connecting two shafts. They are particularly advantageous as they do not tolerate misalignment and exhibit extremely high coaxiality.

The below-listed types of shaft couplings are designed for motion control:

  • High-gain couplings

  • Slit type couplings

  • Bellows type of flexible couplings

  • Disk-type shaft couplings

  • Cross-joint type flexible couplings

  • Rigid or solid type of shaft couplings

Click on this link to visit the page with all types of miniature shaft couplings.

Shaft couplings for "power transmission"

Jaw couplings, also known as spider couplings, are generally considered to be highly advantageous due to their ability to transmit high torque and their excellent tolerance for misalignment. Additionally, these couplings possess vibration absorption properties, making them suitable for a wide array of applications. However, for even greater misalignment tolerance, it is recommended to utilize Oldham-type couplings.

Click on this link for more information about

The below-listed couplings are used for power transmission. 

  • Curved jaw shaft couplings

  • Oldham-style flexible couplings
  • Serration-type flexible couplings

Click on this link to go to the page with all types of miniature shaft couplings we offer.

Special Screws

For high-tech applications, where standard screws are not compatible to use, NBK manufactures special screws from miniature sizes to special materials, coatings, and platings. These screws can be used in applications such as:

  • Ultra-high vacuum

  • Cleanroom

  • High-temperature

  • Anti-reflection

  • Lightweight

  • Anti-theft screws

  • Non-magnetic

Click on this link for more product information about the special screws.

When it comes to special materials, NBK uses a wide range of them. Just to name a few:

  • Inconel

  • Titanium

  • Phosphor bronze

  • Molybdenum

  • Hastelloy



  • Stainless steel 304, 310, 316L

  • Ceramics

NBK strengths for special screws

One of the strengths of NBK is that many of these screws can be supplied from stock. They are available in small batches, on request 1-piece is available. As an extra service, the special screws can be cleaned and packed.

Click here for information about the special screws.