calibration of a cnc

ok now i need some more help, im just about ready to smash this bloody thing. so all the axis are working but now trying to get the voltages right so they run. i dont know what im doing wrong but its getting very frustrating. im getting loud noises, clicking. and when i kinda had it right i decided to run some g code just to see how it went. and well lets just say it was nothing like a square. ive calculated the step via an online calculator.

im using the cnc shield - http://ift.tt/13eZgKk

and the cnc - http://ift.tt/1jtuPLA

steppers - x and y - Nema 23 Stepper Motor 1.26N.m (6.35mm shaft)
and z Nema 17 Stepper Motor 560mN.m

any help would be greatful