To big steppers?

[Sven]

Don't need 8Nm for machine that size if slaved motors 3 or 4nm nema 23 will be more than enough provided the gantry is less than 80-90Kg and your using ballscrews. If used with good motion control card you'll get 12nm or more.

I wouldn't use 2Nm because while they spin faster there will be very little torque left at the Mid/higher end of speed curve which is were you want it while cutting.

8nm would mean Nema 34 which would actually run slower with the same amount of volts. So you'd need more voltage which means larger drives and PSU. Really Large steppers need high power drives that run at mains voltage for best performance.

At 10800 mm/minute (is 10.8 m/minute with 10 mm pitch) the 2 Nm had 0,8 nm of torque left, which is enough for my machine.
The cutting force was set at 100N in these calculations.

I cant run higher speeds on a ball screw of the length I am using.
Steppers with higher torque had a torque curve that plummeted as soon as they start rotating, the 2 and 3 nm motors were comparatively flat.