That little dial near the end of your drill that has the little numbers and then the symbol that looks like a drill bit. You know you’re supposed to use that, right?
I’m no longer surprised when I find people who use their drill/driver without changing the setting (mainly because I come across SO many people who do it). They both drill and drive without changing that little dial. The clutch, as it’s called, basically keeps the drill from rotating once it reaches a certain resistance. Ever hear that clicking sound coming from a drill when watching home improvement shows? There you go.
You should only set your drill/driver’s clutch strong enough to drive screws to the desired point – in most cases, slightly below the surface of the wood or whatever material is in your project. Farther is not necessarily better in this case. Over driving screws can lead to splitting a project part, which then gives you a weaker assembly. You might not even see the split, so be careful. You can even snap off the heads of screws by having the clutch set too high!
When drilling, be sure to set the tool’s clutch to the highest setting. Most drills now have a little symbol in the shape of a drill bit at this setting. That gives your drill the maximum torque. With cordless drills, the higher the volts, the more torque (18v will give you more than 12v).
One side note on drilling – when making a pilot hole (some people call this pre-drilling for a screw) be sure to drill with a bit that is the size of the shank of the screw, not the threads.