hi
i bought this old maxnc10 used a few years ago..never really used it until now

my max nc is very old version is from 1997-1998

all original components..no mods

using the orig maxnc software in DOS and using mach3 software to control machine produces same results

all circles are not round see photo

i have calibrated xy steps and are very accurate
stepper motor couplings are tight
lowered feed rate to 4ipm..no change

im thinking this could be a backlash issue or maybe worn out stepper drives that affect when xy move at same time

i did about 10 holes in aluminum and also HDPE at various depths and all looked very similar ....i did some squares and overall the squares were ok.

any thoughts on this?

note: in the image i attached i used the cad file and node editing to simulate the look of the hole when machined on the max...the hole in cad is round.