Q: What do the variable clutch and drive speed settings on a cordless drill really mean?
A: Before we all started plugging batteries into our drills, our corded predecessors had one speed control at the trigger and no clutch. You got the full dose of torque with every squeeze. These days, manufacturers provide a clutch on cordless drill/drivers with numeric settings on the collar. Its purpose is to disengage the transmission at a range of torque thresholds to prevent overdriving screws in delicate surfaces such as drywall, or damaging small or fragile screws. The higher the number on the collar, the more torque the drill will apply before the chuck stops spinning, and vice-versa. It gives us added control. That second switch for speed settings enables you to choose a higher speed range for faster drilling and driving tasks or a slower range for driving larger bits, mixing paddles and so forth.