After another weekend trying to fix this weird issue, a friend had the idea that I should try running an old gcode created before any changes, such as new motors or breakout board. I did this & my machine suddenly performed as normal. I ran 2 small clock parts. I pulled up that DXF & ran it through aspire again & the new gcode again, created undersized parts with the cog teeth not in proportion. The problem was not my new motors, break out board, backlash or any mechanical issue, it was aspire!!! I have aspire on another computer that runs a CNC milling machine so I created the same gcode on that & transferred it to to my router computer on a USB & it ran fine. Also put that DXF through artcam on the router computer & that worked too. How can aspire corrupt itself in this way. I uninstalled & re installed aspire & while it dumped my tool list, it seemed to have kept some settings & was still not working properly. Time to look for some free CAM software!!! Hopefully this might help someone as it's not always the usual suspects, backlash, play in guide rail or some other mechanical issue. Thanks for all the replies