Power Drills: The Basics
Drills are probably the most common power tool people tend to have around their homes, and it’s easy to see why. They are amazingly versatile.
They can be used to bore holes of varying diameter through wood, plaster, metal and brick, in preparation for screws, wiring, pipes or other fittings; they can be adapted to take screwdriver, cutting and polishing bits; they are easy to use and generally fairly cheap. As ever, they come in all different shapes and sizes, and there are a few things to look out for if you’re buying a new one.
Drill features
The first thing to think about is whether you should go for a cordless or plug-in drill. In most cases the corded drill will mean superior power, lighter weight, lower cost and longer use, so there has to be a good case for going for the battery model.
Other than that, the type of drill you opt for will depend on what you need it for. Check the power and speed specifications; more powerful drills will be more robust but heavier. Many have a variable speed control, either in the form of different settings or on the trigger itself, depending on how far it is depressed.
This is useful because faster is not always better. If you are drilling into tough materials like brick or concrete, you will need a fairly slow speed and high torque (turning force), which allows the bit to keep turning at low revolutions, even into hard surfaces.
Some drills have a hammer action, which also helps to bore holes into hard materials like masonry. Low, controlled speeds are important when using the drill as a screwdriver (as is a reverse gear), and many drills disengage when a certain resistance is reached to prevent over-tightening.
Pic credit: http://www.flickr.com/photos/dcantrell/
