little help needed
i am cutting a groove at 5mm with a 4mm bit but its always 6mm when it comes out could be becouse i have the stepover set at 3mm
any help appreciated thanks
I would suggest you run a calibration of circles and squares. The step over is irrevelant because the size of the slot is the limiting factor not the step over. The step over is shortened when the slot is cut on the second pass. Full step over is only used when the slot is wider than the bit + stepover. So if you had a 8MM slot and a 4mm bit with 3mm step over the Shapeoko would make the first pass at 4mm then move over to 7mm (4+3) and the third pass would only have a 1MM step over cutting an 8MM slot.
If you machine is not cutting the squares and circles the correct size you adjust the stepper motor steps to adjust so it cuts the exact size you requested. See the forum for calibration.
You might want to scale back the step over. You have a 4mm bit with 3mm step over which is 3/4 of the bit width and is a pretty good bite. That can cause the bit to dig into the material and widen your slot even though the machine and Carbide Motion think it is the correct size.