It is not a good idea to use a measuring system to calibrate your axis. The result can only be as good as your measuring. I cannot get down below 1/1000 of an inch with mine, which would leave Mach totally inaccurate for my purpose - which is turning steel. At 1/1000th of an inch over, a steel axle will not fit a steel wheel.
The only method of calibrating is to calculate your steps per unit.
The first thing to do is to decide on which units you are going to settle on and set the machine accordingly on Config/Select Native Units. This does not mean that you can only use what you select (G20 [inches] or G21[millimeters] takes care of that when running programs) but it is the base system on which you set up your machine and all the subsequent tool and program offsets.
It is normally tied to your leadscrew. If you have an imperial leadscrew e.g. 10 turns to the inch, or a metric leadscrew e.g. 5mm pitch generally determines which units you must use. You now calculate and enter enter this in Config/Motor Tuning/Steps per unit.
The calculation then goes like this - AND IT IS EASY, AND ACCURATE
Your motors, if standard steppers, will use 200 pulses for 1 rev. (200). Your drives will have microsteps 8 or ten are usual - my Gheckos have 10 (200 x 10 = 2000). You may have step down gearing to your leadscrew, mine is 3 to 1 (2000 x 3 = 6000) and lastly your leadscrew. I had an imperial leadscrew at first - 10 turns to the inch (6000 x 10 = 60,000) I have just changed to a metric ball screw one turn to 5 mm (6000 / 5 = 1,200).
So my answers for steps per unit were 60,000 steps per inch, or latterly 1,200 steps per mm. The two are NOT the same since changing leadscrew altered the whole dynamics of the lathe table and having changed, I had to set up my offsets and tooling again.
This number DOES NOT CHANGE. You cannot alter it to improve accuracy, it is a matter of fact. If your calculation is clearly way out, you can use a measuring system to check it, but the calculated system is the one that is accurate. i.e. in my case 1,200 steps per mm, not 1,195 or 1,204 or any near number - 1,200 is the correct answer.
Once you have caluculated and entered the figure, then you can check if your table is moving correctly. If it is not, then some other factor is affecting it, but not steps per unit. This may be backlash, you may be missing steps for some reason, or whatever, but deal with that when you have your steps per unit set accurately.