Perhaps, I am wrong here, but 1. this pitch adjustment works. and it make sense to me, because I can explain it - not well made, cheap ballscrews (made in China), so, its precision is far from ideal and it would be reasonable to expect them to perform differently. and difference is not that dramatic - it's just for me makes difference.
BACKLASH is a bit different as I understand it - it is kind of reverse force applied to axis. it is inertia force. it could play significant role when you move your axis fast enough, which is not my case. movements on my machine are very, very slow - because of material I am dealing with and because of cutter type I am using for it. I am using feed rate - 0.09. I wish I could go faster, but experiments told me - I can't.
Do you think I am wrong in what I have said?