Arduino Controlling a stepper motor How can I get an Arduino to do the following to a Stepper Motor installed on a "Lead-screw" attached to my table-saw's Fence?


Turn the "lead-screw" clockwise when I press a given button, UNTIL I release the button.
Turn the same "lead-screw" counter-clockwise, when I press another button, UNTIL I release the button.
Adjust a "speed" knob, to control the motor's speed when the fence is moving; from very fast to very slow; and even stop when the control is completely counter-clockwise.
Turn a switch off, which will remove all control to the motor; so I can turn the shaft manually without resistance, whenever I do not want the fence to be under control of the motor.


That is ALL I need.

It is that simple. So what do I need? What do I need to purchase? I am a novice.
I've got to ask here.  Why use a stepper?
This would be fairly easy with two button switches and a regular DC motor.  One switch provides power to drive the motor CW the 2nd motor drives it CCW.  

You would still need to choose a motor with the right torque but IMHO this method would be WAY easier than using a stepper, and arduino, writing code, etc.