My ACRO 1010 pen plotter is still a work in progress. Started running initial tests with a pen holder I designed and 3D printed. Created a simple svg image in Inkscape to start with, with 3 simple objects - Square, oval, and polygon - which I converted to gcode in CAM, then plotted with BB Control software. Noticed oval does not close its path exactly where it started. It is offset. Ran this test 3 times and got the exact same result. Then plotted "hello world" svg created and plotted the same way. Multiple places where some of the "Os" as well as most of the straight line paths do not terminate exactly where they start. Separate issue (I think) notice the pen paths have a certain amount of line "wiggle". Perhaps this is due to my pen holder design not being solid enough to withstand the drag on it. Not sure about that yet. It feels very solid, but going back to take a closer look at my design. The pen pressure is not spring loaded. It relies on the weight of the moving part of the holder to meet the drawing surface. But either way, it would not explain why the pen paths don't come back to their starting coordinates so consistently. Is there a calibration procedure to perform that will solve this problem?