Method for machining opening in workpieces

Procedure for machining openings in work pieces, in particular of windows in ball cages for constant velocity joints, with the following steps:

• Providing a cutting tool, which rotates around an axis of rotation having two cutting blades positioned alongside of the axis of rotation with a distance to one another (11, 12), which determine a cutting blade axis running through both.
• Supporting a work piece near the cutting tool in a way that an imagined opening axis (9), which runs through two oppositely positioned opening edges (6, 7) to be machined in a predetermined alignment to the cutting blade axis, and
• Machining of the opening edges of the work piece by cutting one opening edge with one cutting blade and the other opening edge with the other cutting blade with both opening edges showing a required distance (8) to one another alongside the opening axis in finished state, characterized by the following steps:
• Positioning of the two cutting blades (11, 12) along the cutting axis (13) at a distance to one another (14), which is greater that the required distance (8) between the opening edges (6, 7),
• Inclination of the opening axis (9) and the cutting blade axis (13) in an initial position at an acute angle (α) to one another so that the distance between the cutting blades (11, 12) parallel to the opening axis (9) is equal to the required distance (8) of the opening edges (6, 7), and
• Reduction of the inclination angle (α) with a wear of the cutting blades (11, 12) so that the cutting blade distance parallel to the opening axis (9) continues to correspond to the required distance (8) of the opening edges (6, 7).