Universal joint can be divided in many different types which used is different machines to have different functions. It is really difficult for the user who want to choose a suitable universal joint but have no thoughts about how to choose universal joint.
A normal, simple "u-joint" has a single cross, and 4 cup style needle bearings. If the shaft angles are perfectly aligned, and nothing ever moved laterally or vertically, you could eliminate the u-joint and drive the car with a shaft of metal. As universal joints have different types into different machines, which type of universal joints should be used correctly? What is the difference between universal joints and CV joints?