Ahh. What might be happening is that when you 'print' the plot to your
plotter from Eagle, it might be trying to shift the output to the left so
that the left hand sides match up or something like that.
What you need to do is plot the top and bottom to separate HPGL files. Then
load those HPGL files up in a HPGL file viewer on top of one another. Most
likely they won't line up correctly.
To solve this problem, draw a single box of copper (like a wire in the shape
of a box) that completely encases your design. Put these copper boxes on the
top and bottom layers. They will be the largest part of the plot, so even if
the printer driver is trying to align the outputs, it won't have to shift
them any.
∗Brian
> Thanks to all who replied! I just noticed something, when i was first
> trying to plot double sided pcbs, I would first plot on paper then
> try to lineup the alignment holes i made on to the paper. However,
> even though i put the paper down on the holes, the plotter would
> always print the holes to the left on the pcb. I am using Eagle Cad
> if that helps diagnose my problem.