if its working OK other than the parts are too big with mach 3's default settings

how big is the error in size ?

you will need to set up mach 3 as in the mach 3 manual


in mach 3

the units may be set up incorrectly what units are you working in ?

eg mach set in inches instead of mm would make parts 25.4 times too big
if Ucancam is set to mm


then you need to check the steps per unit

the pitch of your lead screws may not be the default pitch

John