An electric drill is the most common tool to be owned and used. When you look to buy an electric drill you will hear many things like:

• Corded or cordless
• Power
• Speed
• Chuck size
• Chuck type
• Hammer function

Corded or cordless:

Corded electric drills have a dangling lead with a plug attached to it. It needs to be plugged into an electrical supply. It limits the distance you can work from an electric socket. Corded drills are more powerful and have higher speeds than cordless electric drills.

Cordless electric drills can also give similar performance like most corded drills. They can be used anywhere until the battery pack gets exhausted. Most models have replaceable battery packs.

Power :

The higher the wattage of a corded electric drill, the more powerful it is. Generally they are available in the range 500 to 1000 W. The wattage indicates the robustness of the whole drill. A drill with higher robustness should have more robust bearings and gearbox etc. The more you want to use a drill, the higher the input wattage should be.

Cordless drills are generally rated by voltage. Generally most models will have battery pack from 9.6 to 16 volts. It will be an advantage to have at least one replaceable battery pack.

Speed:

The ideal speed of a drill bit depends upon the size of the bit and the material being drilled. Larger bits have to turn slower than smaller bits. Otherwise they may overheat and lose their cutting edge. It can also put a lot of strain on the motor as it normally runs fast to compensate for its lack of power.

Single speed drills are available, but cannot perform many tasks. One step better from single speed drills are those that offer fixed speeds. One step forward is variable speed control where the speed can be infinitely variable up to a pre-set limit. A trigger generally controls the speed. When you pull it back, it increases the speed of the drill. Generally corded drills offer higher maximum drilling speeds than cordless ones.

Chuck type:

Traditional drill chucks need a key to open and close their jaws to fit or remove the drill bits or attachments. With the keyless chuck, you can fit or remove drill bits and other attachments with the flick of a wrist. Keyless chucks are very useful, as you need not search for the lost key.

Hammer action :

The hammer action function moves the drill chuck rapidly in and out. It causes the drill bit to hammer its way into bricks and masonry. On most drills the hammer action is created by a ratchet mechanism. It makes the chuck jump up and down as it rotates. It requires pressure to be applied by the user. The harder the material, the more pressure has to be applied. Most models with hammer action have a switch to select or deselect the hammer action. It adds to the versatility of the drill.