My first attempt at 3D carving on my Chinese 6040 router came out really well and so did the next one, but now when I start the Z axis is getting higher the longer it runs, on a file that is 200 x 150mm after a quarter of the way through it ends up being 8mm above zero, I’ve checked to make sure everything is tight and running freely, not sure what is going wrong. Regards, Attachment 27523Mike.