How to Choose Power Drills
Determine the main purpose of the drill.
For common household or hobby projects, a basic variable speed reversible (VSR) drill will work fine. For drilling into stone or concrete, a hammer drill is a better choice.
Assess how much power you need.
Cordless drill power is measured by volts and ranges from 9.6 volts to 24 volts; larger voltage meaning more power. Cordless drills are a good choice for everyday, around-the-house applications. For basic home repair and some light to moderate construction tasks, a 14.4-volt cordless drill or 8-amp power drill will likely be a power tool that will suit your needs.
Figure out the size of chuck that you need.
The chuck is the slot where the drill bit is inserted, so the size of the chuck limits the size of the bit you can use. Available chuck sizes are 1/4 inch, 3/8 inch and 1/2 inch. A good size for most homeowners or hobbyists is 3/8 inch. Chucks are keyed or keyless. If a chuck is keyed, you must use a key to unlock the chuck in order to change the bit. If the chuck is keyless, you can loosen the chuck by hand and change the bit. The keyless chuck is easier to use if you are wearing safety gloves.
Decide on a cordless or corded drill.
Corded drills are often lighter than cordless drills because they lack battery weight. Because corded drills run off regular electricity, they are always ready to use, but the cord may get in the way. Cordless drills are often heavier than corded drills and can run out of battery power before you’ve completed your job, but they are more flexible to use, as they do not depend on an electrical outlet to power them.
Consider whether or not you need a clutch.
A clutch allows you to adjust the torque of the drill when faced with a change of density in materials. Adjusting the clutch can help prevent stripping or breaking screws.