Not sure what exactly you meant by pulled in 20-30 degr., are you saying you encountered Tool deflection meaning the tool gets pushed away from the surface?
Are you using the stock leadscrews?
A 2 flute or a 4 flute, carbide or hss cutter?
What feedrate did you use, and coolant or dry?
What was the Spindle Speed?
If you give us some more info we may be able to make some suggestions.
Congratulation on getting your mill converted, is this stepper or servos.
How did you do you Z-Axes?
I converted the same Machine, actually still finishing up on it.