You can setRange(0, 50), setSingleStep(1) and divide by 50 instead of 10 to get the step size of 0.02.

To make the step even smaller you can setRange(0,1000), setSingleStep(1) and divide by 1000.

pageStep defines how much internal counter changes when PgUp/PgDown are pressed.

pageStep : int

This property holds the page step.

The larger of two natural steps that an abstract slider provides and typically corresponds to the user pressing PageUp or PageDown.