Oval instead of circle

[cnc_freak]

In a large gantry machine measuring 10 meters in width, I conducted a pen trace and obtained the results depicted in the accompanying images. When I drew a circle in a clockwise direction, the resulting shape appeared as an oval, with the longer diameter rotated approximately 45 degrees clockwise, as shown in picture 1. Conversely, when I executed the same movement in a counterclockwise direction (picture 2), the longer diameter of the oval was rotated 45 degrees counterclockwise. I did not observe any backlash in either the X or Y axes. The Y axis is equipped with two motors configured in a master/slave arrangement. I attempted to misalign the two motors by a maximum of 30 millimeters; however, due to the rigidity of the gantry, further misalignment was not feasible, and there was no significant alteration in the circular or oval traces.
When i did the same pen trace with a bigger circle, (diameter 300mm) the error was about the same 305 mm in the long oval axis and 299 in the small.
Al the three motors are analog servos .

What else should i check?
Regards.

[TomKerekes]

Are the axes tuned well to have small following errors? Set the Max following error to the equivalent of 1mm and see if you get an error.

[cnc_freak]

The following error was very big, when i decreased to 10mm (500, the cnts/mm is 50) i had an following error on ch0 the master/slave are ch0/ch1.

[TomKerekes]

That would indicate the axes are not following well. Check the servo tuning using the KMotion Step Response Screen.