From the perspective of lathe, what are the reasons for the pitch out of tolerance of Turning Thread?

(1) The axial movement of the lead screw is too large.

(2) The opening and closing nut is worn, and the coaxiality with the lead screw is out of tolerance, resulting in poor engagement.

(3) The dovetail guide rail is worn, causing instability when the opening and closing nut is closed.

(4) The clearance of the transmission chain from the main shaft through the exchange gear is too large.