testing for squareness

Responses to the questions from Craig Libuse on the Sherline
list: "Instructions on squaring up a machine can be found on our web
site at

www.sherline.com/2000inst.htm.

<<I was told one way to test for squareness is to machine a circle.
If the x and y axes are not 90 degrees to each other, the circle will
not be a perfect circle.>>

"Keep in mind that when machining a circle with a CNC machine that
does not have ball lead screws, any backlash in the X and Y will show
up as an "out of round" condition as backlash is pulled out of the
leadscrew with a change in direction. This is not a function of it
being out of square."