Rigid Shaft Couplings - When the application requires a direct and solid shaft connection and that shaft misalignments during operation are minimal, then the ABR solid or rigid type couplings can be used. To suit shafts from 6mm up to 50mm in diameter as standard.A solid compression-type coupling or rigid coupling as it is sometimes termed has no flexibility but can effectively be used to connect two shafts to make a permanent joint. The solid coupling is usually designed to be capable of transmitting the full torque load capacity of the shaft.