Glossary of linear technology | Dr. TRETTER 

In our glossary we would like to explain frequently used terms:

Eco Rail Guide

The Eco rail guides are a low-cost alternative to our premium rail guides from NSK . They comply with the ISO standard and are thus compatible with the connection dimensions of most profile rails...

Shaft Guidance Systems

See also: Ball Bushing Guide

Lead Screws

A ball screw is a machine element in which a shaft is provided with an external thread. This can be a simple screw thread, a trapezoidal thread or a round thread, which is introduced by rolling,...

Ball Spline

See also: Grooved Shaft  

Torque-resistant Ball Bushing

In contrast to a conventional linear ball bushing , which runs on a smooth shaft and thus has to be additionally secured against rotation, e.g. by using a second guide shaft, a torque ball...

Ball Bushing Guide

A ball bushing guide is a so-called round or shaft guidance  in which a linear guide is realized via usually two parallel shafts as a guide element and in which linear ball bearings,...

Cross Roller Guide

In contrast to a profiled rail guideway, a cross roller guideway is a linear guideway for limited stroke lengths.

Ball Screw Spline

A ball screw spline generates a stroke and rotation movement of an output shaft that can be combined as desired via the rotary movement of two drives with simultaneous backlash-free guidance of...

Rotary Ball Bushings

In contrast to normal ball bushings, which only provide a linear bearing support for a guide shaft, a rotary ball bushing can also provide a rotary bearing support for the shaft.

Floor Plastic Caster

The floor plastic caster is primarily designed for easy movement of objects when installed with the ball facing down. In contrast to a swivel caster, it allows faster changes of direction with...

Aluminium Rail Guide

The aluminium rail guide is a 2-row recirculating ball bearing guide with carriage and profile rail made of aluminium with hardened and corrosion-resistant raceway inserts made of steel.

Slipping Clutch

A slip or overload clutch slips when a certain torque is reached, thus preventing damage to mechanical components such as gears, motors, etc. due to overload.

Roller Guide

A recirculating roller bearing guide is a (profiled) rail guide in which, in contrast to a recirculating ball bearing guide, rollers are used as rolling elements.

Track Rollers

See also: Track roller guide

Frictionally Connection

See also: Force-locking connection

Hardened Shaft

For use as guide shafts, the steel shafts must have a hardened surface. This guarantees that the balls of the ball bushings running on them do not run in due to the small contact surface.

Grooved Shaft

Grooved shafts are used in linear technology to transmit torques with simultaneous linear motion. They serve as a torsionally rigid linear guide or as a drive shaft with a linearly displaceable...

Peeled Ball Screws

See also: Whirled ball screws


The repeatability describes the deviation with which a certain position can be reached when approaching repeatedly from the same direction.

Positioning Accuracy

The positioning accuracy describes the deviation from the desired position, resulting e.g. from a calculated number of motor steps, and the position actually reached.

Linear Axes

A ready-to-install linear system consists of an inherently rigid base body.

Round Guide

In linear technology, a linear guide with shafts as a guide element is also referred to as a round guide or shaft guide.


To eliminate backlash and increase stiffness in a linear guide or ball screw , they can be provided with preload

Tolerance Ring

Tolerance rings are slotted sleeves made of spring band material, which have wave-like corrugations.

Whirled Ball Screws

In whirling, the thread is machined by means of a tool rotating around the hardened and ground raw material.

Ground Ball Screws

By grinding the ball screw, the highest precision can be achieved with regard to pitch accuracy of the thread and concentricity, of the usually already finish-machined screw ends.

Rolled Ball Screws

In the case of rolled ball screws , the particularly low-cost version, the thread is produced by rolling without cutting.

Trapezoidal Screw Drive

In this most economical form of lead screw, the negative profile of the trapezoidal lead screw is cut into the nut, so the transmission of the feed motion takes place via sliding friction.

Screw Drive

Screw drives are a drive element that converts a rotary motion into a linear feed motion via a screw thread (lead screw).

Dynamic Load Rating C

The basic dynamic load rating is a measure for the service life calculation of a linear guidance system as well as spherical plain bearings and rod ends.

Torque Transmission

If a shaft-hub connection can also transmit drive or torque forces in addition to axial forces, this is referred to as torque transmission.

Static load rating Co

The basic static load C 0 is a measurement of force or load applied to machine elements .

Ball Screw

Ball screws are a drive element that converts a rotary motion into a linear feed motion via a screw thread

Recirculating Ball Bearing Guide

A recirculating ball bearing guide is a special type of linear guide with ball bearings.

Track Roller Guides

Track roller guideways are economical linear guideways for lower loads and subordinate guideway accuracy.

Rail Guide

A rail guide is a linear guide with rolling bearings based on the recirculating ball / roller principle for unlimited linear movements.

Ball Transfer Unit

A ball transfer unit consists of the load ball and a number of small support balls that roll on a hardened support shell, allowing the ball to rotate in all directions with low friction.

Shaft machining

In addition to the function of shaft guidance , hardened and ground shafts are also used in a wide variety of industrial applications as drive shafts, axles, rollers, pins or centering pins.

Ball Bushing

Linear bushings are roller bearings for longitudinal movements, in which the balls are returned to the load zone by closed orbits in continuous circulation.

Linear Technology

The field of linear technology is a sub-discipline of drive technology that deals with the mechanical components or systems for executing linear movements.

Linear Guide

A linear guide , or straight-line guide, is a mechanical guide element.

Force-Locking Connection

Various types of connection are available for joining two or more components. One of them is the frictional connection.

Shaft-Hub Connection

The term shaft-hub connection is used in mechanical engineering to describe the standardized connection of a rotationally symmetrical inner part to the receiving bore of an outer part