Ruland rigid couplings are available in one and two-piece designs, with and without keyways, in aluminum, carbon steel, and stainless steel. A large number of standard sizes are available in straight and step bore combinations to fit shafts ranging from 1/8" to 2" in the inch series and from 3mm to 50mm in the . Inch to metric conversion couplings are also available by special order. Shaft couplings are stamped with the Ruland name and the bore sizes for easy identification.

The one-piece rigid coupling wraps around the shaft, providing high torsional holding power without the shaft damage and fretting inherent when a set screw style coupling is used. The two-piece rigid coupling has the additional benefits of allowing for disassembly and maintenance without removal of other components. Two-piece couplings also feature opposing hardware for dynamic balancing.

Extra steps are taken in the manufacturing of rigid couplings to provide important performance benefits. As one of these steps, the bores of Ruland straight bore couplings are precision honed. Honing of the bores provides several benefits that enhance the overall performance of the coupling. Applications that require strict control of shaft alignment benefit greatly from honing, which assures both bores are collinear. Honing also corrects any residual distortions caused by stresses introduced during the manufacturing process, resulting in a round, precisely sized bore. Proper sizing and geometry assures a large percentage of shaft contact and greater torque transmission ability.

The rigid coupling comes with Ruland's unique Nypatch® socket head cap screws for increased performance and reliability. Nypatch® is a proprietary process that involves depositing a 360 degree coating of Nylon on several threads of the socket head cap screws. This coating is designed to reduce screw vibration, which can cause the screws to loosen and torque transmission ability to diminish during the course of normal use. The Nylon also provides the necessary dissimilar material to reduce galling of the screw threads in stainless steel couplings.

The benefits of a rigid coupling include its economy, high torque capacity, and zero-backlash. It is suitable for applications when misalignment is neither present nor desired, including connecting line-shafting and attaching a motor to a gearbox. Rigid couplings are increasingly being used in precision motion control applications with properly aligned components.