1400mm axis on 8mm x 1mm leadscrew is a bit iffy, both from a whipping perspective and speed, you'll struggle to get better than 600mm/minute which is a very low traverse speed for a 1.4m axis. That's not to say it can't be done, but its hard to get it any better because the efficiency of the screw is so poor and it ideally needs to be geared up to get the motor running closer to its corner speed. and maintain torque My first build was 800mm on 12mm x 2mm trapezoidal but its tediously slow as the motors cant do more than 400rpm i.e. 800mm/minute and a minute feels like eternity, and anyway the acceleration is so low that the real achievable cutting speed is 1/2 that.