This Boston Gear JP623/8 single universal joint is a molded coupling for connecting two rotating shafts at angles up to 45 degrees. It compensates for angular misalignment and shaft separation and has a single joint configuration for high torsional stiffness and torque capacity. It has a molded polymer body for vibration dampening and electrical insulation, and it has a nickel-plated brass spider and insert for resistance to corrosion. Set screws secure the joint into position on the shafts, and each hub has a .375" bore for connecting shafts of the same diameter. It has a maximum ambient temperature of 180 degree F. This universal joint provides a uniform speed ratio between driving and driven shafts, and is suitable for applications requiring moderate torque transmission, such as farm implements, material handling equipment, and drive shafts.

Universal joints (also called U-joints, universal couplings, Cardan joints, Hooke’s joints, or Hardy-Spicer joints) are used to transmit motion and rotational power, or torque, between two shafts that are offset at an angle. Most universal joints consist of two yokes and a middle assembly; the hub end of each yoke attaches to a shaft while the yoke ears attach to and pivot around the middle assembly to accommodate shaft misalignment. The type of middle assembly determines its usage—pin and block joints are suitable for transmitting high torque, needle bearing joints are used to handle high rotational speeds, and ball and socket joints are used in applications requiring low backlash (play between moving parts). The body of the universal joint may include a single joint to accommodate only angular misalignments between shafts, or two joints to accommodate both angular and parallel misalignments. Available in a variety of materials and configurations, universal joints are used in applications including motor vehicles, conveyors, medical and optical devices, forestry and mining equipment, robotics and space exploration, and aeronautics, among others.

Boston Gear manufactures gears, gear drives, bearings, valves, shaft collars, couplings, and other power and fluid transmission components. The company, founded in 1877, is headquartered in Charlotte, NC, and meets International Organization for Standardization (ISO) standard 9001:2008 standard.