Machining of mirror geometry cylindrical parts

It is difficult, especially for small manufactures and hobbyist to manufacture parts with a better precision and quality. One such case is a simple circular slide (see figure above). The circular slide consists of a rotating part and two fixed side slides. The fixed slides allow the rotating part to rotate only from its periphery and leaving in this way the center area completely free. The slides apply a form closed joint (see figure below) which can be manufactured with very tight tolerances. The rotating part must be concentric with the two slides and the sliding surfaces must have exactly the same size. In different case the parts will jam.

When we try to manufacture the slides with a milling machine (CNC milling), although the tool path will be accurate, the correct clamping (with exactly the same references) will lead to not functional parts. The problem is the part’s orientation prior to manufacturing.
The best approach will be to manufacture the two slides as one part. Observing the two slides carefully we realize that they are identical with mirror geometry (left and right). This make possible to manufacturing both parts the same time with same tool and in one clamping. If the rotating part has been already manufactured, it can be used as gauge during the machining of the slides. Fitting the rotating part we can adjust the clearance of the sliding feature. Frequently identical parts are machined as one (see figure below) and then sawed apart.