Stepper motor driver not working properly
The &quot;metal screw&quot; is a &quot;trim potentiometer&quot; that is used to set the current used to drive the motor. It sounds like you may be altering the current when you push against it. Try turning it to different angles to see what effect that has on the motor.
Alternatively if it only ever works when you push on it then it could be that you have a faulty potentiometer on your board.