There does seem to be a problem with the Warco Mini mill. I have just recently bought one and the X Y axis are not at 90 degrees. I too will have to get mine machined. The error I measured was 0.25mm over 100 mm on the Y axis. This is a pain to have to correct on a brand new machine. It came with a test certificate that stated it was measured at 0.025mm over 150mm. Clearly the machine was not measured.

John