RACO trapezoidal thread spindles (TR) consist of a vortex or optionally ground spindle in combination with a spindle nut made of special bronze. Depending on the choice of spindle geometry and the drive, self-locking at standstill is achieved for this design. Even high static loads above the nominal dynamic load rating are safely held in any intermediate positions. Higher positioning speeds and lower friction are achieved by using multiple trapezoidal spindles.

At the same time, the surface quality prevents the "slip-stick effect", which describes the jerky sliding of solid bodies moving against each other. RACO also manufactures so-called hydrostatic spindles for this purpose.

Grinding in an air-conditioned room requires both compliance with tolerances for holding the workpieces in the machine and their dimensional accuracy in terms of concentricity and axial runout. The pitch distortion caused by heat input (whirling & hardening) is corrected and thus eliminated during grinding.

We produce trapezoidal screws using the so-called whirling process, a metal-cutting process in which a tool gyroscope rotates around the raw material rod. In the process, the gyroscope is displaced from the centre of the axis and thus cuts a chip from the raw material. If the gyroscope is now provided with an axial feed, a thread is produced.

Advantages of the whirling process:

• The tools are independent of diameter, profile and pitch.
• Low tool costs
• Cost-effective for small batch sizes

Parameter Name	Parameter Value
Options	trapezoidal bronze