Having an odd mischatch with mirrored carves

Hi all. I am hoping someone can help me. I am carving a double sided design that is simply a mirror of the other side. I have set up with pins in the waste board so that when I flip the material it lines up for the mirrored cut. both cuts use the same 0,0,0. fairly simple.

So the problem. The 2 sides dont match but heres the odd part. The start of the cut is fine, the bottom and one side are perfectly lined up, so I know my 0,0,0 is correct. But when it get to the top part of the design it goes out of alignment by 2mm on the y axis. I have checked the design and even re mirrored and re set the pins but the same each time.
Its almost as if the machine is bending the design in one direction. I cannot fathom the problem.

Thanks in advance


You may want to verify that your router / end mill is trammed (truly perpendicular relative to X/Y plane
Any deviation in flex in X and Y will affect things aswell (if X is stiffer than Y, the carve will be more true in X)
Finely tuned step/mm per axis`
If you carve a circle of like 8" is the dimension in X and Y direction exactly a match?

Ah yes I see. I did lossen off the Y . maybe to loose. I will try cutting the circle in the morning

Only thing is that the deviation in the cut is only in the -Y . If the Y was too tight would I not get the deviation in both the + and -

Also check that your X is square to Y before you turn on the machine.

Think I have figured it out. The Y carrage was too tight and the belt not tight enough. Feel a bit silly :slight_smile: