Below are the first cuts on CNC Jr. on some scrap MDF. The bottom "TEST" is at 500 mm/min, the middle at 200 mm/min and top at 100 mm/min. This is G-Code from F-Engrave, just to test the machine. I used a serif font on the top two to make more steps out of it. The line through the bottom TEST is a lesson in not to use return-to-zero in UGS after a job is done. At the lower speeds, it's going haywire. I am thinking this is my X-Axis driver having issues, but it doesn't seem to be overheating once I put a fan on it. I'm using DRV8825's, 12V PS, CNC Shield, GRBL. I have a 24V PS, perhaps I should try that to get the current down? Any tips?