Whether you are busy diy-ing every weekend, or only ever put up the odd shelf, a power drill is one piece of equipment every home should have. Finding the right drill for your particular needs depends on many things, but possibly the most important quality the average diy-er’s drill should have is versatility.
Chuck size and type
The two main things you need to think about when choosing a new drill are chuck size and power. Chuck sizes range from 1/4 inch (7mm) up to over 1/2 inch (13mm). Larger sizes are available, but very few, if any, diy jobs will require a chuck bigger than 1/2 inch. A good average size to look for is 3/8inch (10mm) as this will be able to handle most diy jobs. It is possible to buy drills with a selection of interchangable chucks for different sized jobs.
Several years ago, your only choice for type of chuck would have been one with a chuck key, a round, toothed key to undo the chuck. Nowadays, most drills use a keyless chuck which are tightened and released by turning the two locking barrels in opposite directions. There should be no real difference in how either locking option works, other than time taken.
A third type of chuck is available, and that is SDS. SDS (Special Direct System) drills are designed to increase the hammer action when drilling masonry, etc, but can also be used without hammer and even with just hammer and no rotation. SDS chucks are completely different to normal chucks, meaning standard drill bits will not fit without an adaptor. In most cases, you will not need SDS for diy jobs.
Drill power is measured in two ways, depending on whether it is a corded or a cordless model.
The power of Corded Drills is measured in terms of Watts and range from 500w to over 1200w. Corded drills tend to offer more power than cordless drills of the same price, but it is always worth considering where you will need to use the drill most. You will obviously be restricted to where you can use it by the length of the cord, unless you also have a heavy duty extension lead.
Cordless drills are measured by Volts and range from 9.6v to 24v. You can buy higher voltage cordless drills but they are usually very expensive and not really needed for most diy tasks. Cordless drills are obviously a lot more portable than corded drills, but it is worth considering the battery. If possible, buy a cordless drill with a spare battery, so when working, you can always have one battery charging up ready to use.
There are three main battery types used in cordless drills. Ni-Mh (Nickel Metal Hydride), Ni-Cd (Nickel Cadmium) and Li-ion (Lithium Ion). The main difference between Ni-Mh and Ni-CD is that a Ni-Mh battery can hold 2 or three times the charge that a Ni-CD battery can. This is usually reflected in the price and the charging time. Li-ion batteries are the best of the lot, being lighter and holding more charge than the other two types. Again, this is reflected in the price.
Most modern drills offer variable speed controlled by the amount of pressure on the trigger. For the average diy-er, variable speed is a must! You can get single or duel speed drills, but they will not offer anything a variable speed drill offers, so why not have the option of a range of speeds, rather than just one or two?
The added bonus of a variable speed drill is that it will usually be able to be used as a screwdriver as well. Single or duel speed drills will not, as they spin too quickly. Variable speed drills have a low speed start and high torque. This means starting a hole in a piece of material can be easier and more accurate.
Both corded and cordless drills are available with variable speed.
The above features are the main things to consider when buying a new drill, but there are several other things you might also want to think about.
Not all drills feature hammer action for drilling into masonry. It is, however, a very useful option to have on any drill you buy. Using the hammer action a lot, or putting too much pressure on the drill, could reduce its life. If you have a large amount of holes to drill in masonry in one go, consider hiring a SDS drill.
Variable Torque and reverse
Lots of modern drills have the ability to increase or decrease the torque. This ensures the drill does not overscrew or strip a screw when driving it. Better drills could have up to 16 torque settings.
Reverse gear is standard on all bu the very cheapest drills. Useful for backing out drill bits which have jammed in the material, and also for unscrewing screws quickly. If the drill you are considering does not have the reverse function, think about a different drill!