Those who use an electric drill as a lathe might be interested to look at these pictures. You'll see a device that allows you to control the drill's revolution and have both your hands free. The point is that you fix the controlling knob of the drill in a position that gives the number of revolutions you need.
Step 1: A View of the Device
This is another view of the device. I give you a general idea, you are free to improvise as to shape, dimensions, etc.
Step 2: The Set-up Screw
You establish the required number of revolutions by turning this screw.
Step 3: The Nut Is Fixed This Way
The nut of the set-up screw is fixed with 6 small pieces of wood that form a kind of a star. You can choose another arrangement. You can also install a kind of knob on the screw's head, to turn it with your bare hand and not with a screwdriver