I ordered 4x ballscrews for my 4x4 machine off chai. All are good apart from the y axis one which seems to be bent towards the motor end. This results in the driver stall detect coming into play when the z moves into that area. Was thinking about trying to straighten it myself, but not too sure...
i would e-mail him your concerns, get them bolted in place and run them off the steppers and see how they look then. If you are still concerned e-mail chai to see if he will replace them.