A spring automatically lengthens or shortens these U-joints to fit your application, making them a good choice for assemblies with frequent changes. And since they connect to shafts using the included set screws, there’s no drilling required, unlike U-joints that use spring pins. As double U-joints, they connect and transfer torque between two shafts that are either parallel to each other or are misaligned at an angle. They also keep parallel shafts moving in sync by making the output shaft move at the same rate as the input shaft. With a pin-and-block joint, they handle higher torque at lower speeds than other joint types, making them a good choice for most applications. Made of steel, they’re strong and withstand a good amount of torque.

To extend their life by keeping lubricant in and contaminants out, use the grooves on their body to add a cover (sometimes called bellows or boots).

Your shafts’ misalignment will affect the speed and torque the U-joint will be able to transmit. The more the shafts are misaligned, the less speed and torque the U-joint will be able to transmit.