An adjusting handwheel mounted on the hollow axle is rotated, and the spiral wheels rotate accordingly.

The setting component is used so as to ensure that a surface (6) of the control wheel is aligned with a guide surface (18) of an outlet guide (16) so as to facilitate accurate machining.

A centreless grinding machine (2) having a control wheel (4) and a grinding wheel (8) for machining cylindrical workpieces is adjusted prior to a machining operation using a setting component (20) having the same diameter as the workpiece.

Relative movement of the control wheel and the outlet guide enables an electrically conducting portion (22) of the setting component to complete an electrical circuit (28, 34, 36) when the two surfaces (6, 18) are in alignment.