If you have two motors on your gantry this is usually a result of one motor losing connection. If you reset your controller box it will normally reconnect. In my situation I identified it was a cable issue. I replaced the cable and it fixed it. I'm preparing the replace the cable on the other side this weekend. To identify if this is your issue, after you observe this problem, use your hand to gently put pressure on each side of the gantry. When the motors are connected they should hold the gantry rock solid. If one side has movement, that motor may have lost connection.why the wavy cuts? mine does that on and off but can't figure out exactly when or why.
Man. That's frustrating. You might take a look at whether it just happens on either the X or Y axis only and whether it happens in just one area of the table. You'll have to burn some steel but I'd lay out an array of 3" squares over the entire 2x2 area, all separated by 1/4". Cut them all and analyze the results. If you see an issue I would do it again to confirm. And then work from there.it's hard because one cut may do it and one may not. the next day it may be fine
I cut rather decent size parts so it's not one area of the table.
Also the torch mount is rock solid. I check it often, plus like i said it's weird. It will do it one day then I come back the next day and it's perfectly fine
Anything you recommend to spray on the drive screws?