Wider selection of series products

Wider selection of series products

Ruland now offers rigid couplings with combinations of metric and imperial bores as a standard product. This means that users now have a larger selection of couplings available as standard.

This expansion is the latest addition to the coupling specialist's standard metric-to-oil bore products, which already includes seven types of motion control couplings as well as universal joints. Rather than reworking or custom ordering couplings, using off-the-shelf couplings with metric-to-inch bore combinations saves time and money.

Ruland rigid couplings are often used to couple motors or gearboxes to ball screw drives or lead screw linear actuators. Many designers prefer rigid couplings because they are more precise and can transmit significantly more torque than flexible couplings of the same size. One-piece couplings allow for easier assembly, while two-piece couplings are balanced by design to ensure smooth operation at speeds up to 4000 rpm. Ruland supplies clutches in clamp design with high-quality DIN 912 screw material, which exceeds the requirements of strength class 12.9. They are coated with a patented Nypatch anti-vibration coating that ensures optimum performance in terms of holding force and torque transmission in most industrial operating environments.

"Ruland is known in the flexible coupling world for the widest range of standard bore sizes, including combinations of inch and metric bores," says Bill Hewitson, President of Ruland. "Expanding our line of rigid couplings to include these metric-inch bore combinations gives design engineers more flexibility to find the coupling that best fits their application - whether it's a rigid or flexible coupling."

Ruland sources the bar stock used for the couplings from selected steel mills in North America. The rigid couplings are available in high-strength aluminum 3.1355 for low weight and low inertia, in lead-free 1.0736 steel for optimum torque transmission and in stainless steel 1.4305 or 1.4401/1.4404 for increased corrosion resistance. The couplings are manufactured in Ruland's ISO 9001:2015 certified production facility near Boston in the USA under strict quality controls and using proprietary processes. They are RoHS3 and REACH compliant and in accordance with the Conflict Minerals Rule.


  • Ruland is expanding its range of metric-inch couplings to include rigid couplings, giving users a wider choice of couplings available as standard
  • The standard product line with metric-inch bore combinations includes seven types of motion control couplings and universal joints
  • Metric-inch bore combinations give designers more flexibility in selecting the right coupling for the application
  • End users save time and money when using couplings with metric-inch combinations
  • Rigid couplings from Ruland do not introduce any misalignment or vibrations into the system and are therefore suitable for high-precision servo applications and shaft-to-shaft connections
  • Ruland is the only manufacturer of straight bore rigid couplings with precision honed bores that provide excellent fit and optimum torque transmission and alignment