Method of and apparatus for grinding control edges of a control bush

Apparatus for a control bush of a rotary slide valve for use in hydraulic steering of motor vehicles for subsequent centerless grinding of control edges of the control bush, comprising:

• support means for securely holding a control bush that defines an interior space and is formed with a plurality of circumferentially spaced grooves bound by edges to be ground for formation of control edges of the control bush;
• grinding means including a grinding wheel for machining the control bush;
• a mandrel press-fitted in the interior space of the control bush for adjusting an angular position of the control bush in relation to the grinding wheel;
• measuring means for determining a reference point of the angular position of said grooves and forming signals commensurate with each reference point being determined;
• and
• control means receiving the signals for calculating from the individual reference points an optimum reference point for positionally adjusting the mandrel and thereby setting the angular position of the grooves of the control bush for allowing formation of control edges through grinding in accordance with a given angular pitch of the control edges.