Hi guys, 1. In this video: Could someone explain me how the linear stepper motor responsible for drawing/injecting the syringe works? I mean, the threaded rod going through the motor is suppose to turn around its axis in order to advance linearly and in this mechanism there's a rail to the right/left to make sure it dosen't. So how does it still move linearly ? 2. With external stepper motors could someone please explain if the external linear nut rotates and moves along with the threaded rod or does the threaded rod simply rotates without moving linearly like a non-captive motor and the nut rotates and moves along it? Example: http://www.haydonkerk.com/LinearAct...size_8_external_stepper_motor_linear_actuator 3. Is there a way to reduce step angle from the typical 1.8 deg per step to 1.4 deg without using gears? Like when using linear stepping motors, is there a way to control that via the threaded rod? Thanks a lot!