Performance Data.

A universal joint (U-joint) connects two rotating shafts that aren’t perfectly in line, letting power transfer around an angle. It consists of a cross-shaped center piece (the “spider” or “cross”) with four trunnions, each riding in a bearing fitted into a yoke on either shaft end. As the shafts rotate, the cross pivots within the yokes, letting the joint flex through the operating angle while still transmitting torque.

This is a needle-bearing industrial U-joint sized by bore diameter rather than an automotive series number — confirm your shaft is 5/8 in with no keyway or setscrew required, since this joint has a plain round bore. Check the static breaking torque rating (2,500 in-lb) against your application’s load with a real safety margin — static breaking torque is the failure point, not a continuous operating rating, so don’t size a joint to run anywhere near this figure.

Keep your installation’s operating angle within 25°; anything needing a greater angle should use a double universal joint (two joints in series) rather than running a single joint past its rated angle. Also check max speed (6,000 rpm) and operating temperature range (-30°F to 212°F) against your application.

Needle-bearing round-bore U-joints like this one are common in machine design, robotics, test equipment, and light industrial linkages where a precise bore-to-shaft fit is needed rather than a vehicle-specific yoke — anywhere two shafts meet at a working angle and a keyless, set-screw-free connection is preferred.

This NB8B size has a 5/8 in bore (no keyway, no setscrew) and a 1.25 in outside diameter. Lovejoy’s NB series also comes in NB6B (1/2 in bore) and NB10B (3/4 in bore) if you need a different shaft size.