@GeoffH I am opting for 0.02-0.04mm precision on the accuracy of the whole system ... It's a bit optimistic for a wooden CNC but I always have high hopes

 

What do you mean with "Beauty Star" is it a supplier/brand/... ?

I have opened one of the drives and found out that there isn't a TB6600 chip inside... Instead there is a TB67S109AFTG inside which got similar ratings... I have ran a test at still 1/4 (800steps/rev) microstepping which resulted in following errors (roughly):
-50% +- 0.01mm
-40% +- 0.02mm
-10% +- 0.05mm



Video to one of the tests...(the sound is a bit lousy because it's recorded with a toaster when you hear nothing it's running Y or Z axis moves like ramping in and out or so)
___WA.mp4

 

I have found a seller on amazon that hat quite a good page on TB6600 and confirms that there is a TB6600 chip built in.. I won't by the yet but if my drivers doesn't work and the a4988 are overloaded or even fried by the 2Amp motors I would buy them (In case you really don't suggest that / suggest a better supplier / suggest other drivers (I don't like to buy drivers for 40€ each )

 

Unfortunately they don't ship to Germany... But I now bought those ones I posted before...(pray for me that these work)