Circuit - The continuous closed path of recirculating balls in a ball nut.

Ground Threaded Ballscrew - A ball screw that has threads that have been precision ground.

Lead - Actual distance the screw or nut travels during one revolution.

Lead Error - Deviations of motion which are due to manufacturing variations.

Machined Threaded Ballscrew - A ball screw that has threads that have been machined on a mill or lathe.

Major Diameter - The outside diameter (largest cross section )of the ballscrew shaft.

Rolled Threaded Ballscrew - A ball screw which has threads that have been produced on a thread forming (rolling) machine.

Minor Diameter - Diameter of the screw measured at the bottom of the ball track (smallest cross section).

Multiple Lead Screw - A screw thread which has more than one start. This directly affects the motion of the nut or screw in that the lead multiplied by the pitch equals motion. i.e. a 4 start screw with a .100" pitch will cause .400" motion per revolution.

Self Locking - A screw and nut that will not backdrive is self-locking. Single lead Acme screws are self-locking. Other multiple lead screws may backdrive.

Pitch - The pitch of a screw thread is the distance from one thread groove to the next measured axially.