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| Power rating | ||
| Voltage (cordless only) is directly related to the power of the drill - the higher the voltage the more powerful the drill. Voltages range from 7.2 volts to 24 volts. A higher voltage drill delivers more power, so you'll finish the job faster but as a general rule, the higher the voltage, the heavier the battery. A larger battery doesn't necessarily mean the drill can operate for longer. A 9.6-volt battery may operate for the same amount of time as an 18-volt battery before it needs recharging, but the higher voltage drill will get through more work in that time.
Wattage (corded only) - a higher wattage gives more power for heavier tasks and can work for longer without the risk of overheating. Generally, the higher the voltage or wattage, the higher the price of the drill. |
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| Chuck type and size | ||
| The chuck is the mechanism that holds the drill bit securely in place. There are three main types of chuck: keyless, keyed and SDS. Chuck capacity dictates the largest size of bit or other accessory the drill can take (though the maximum diameter of hole that can be drilled may be larger). A minimum of 10mm is adequate for most purposes. | ||
| Keyless chucks Most drills come with a standard 13mm chuck, which allows you to change the drill and screwdriver bits without having to use a special key to release and tighten them. Changing drill bits is quick and easy - this is useful if the job involves frequent bit changing. |
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| Key-operated These drills are tightened using a locking key. Changing bits takes a little longer but the bit can be more tightly locked in place, which prevents bit slippage when drilling through hard materials. Chuck keys can easily get lost - beware! |
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| SDS chuck This is a quick locking keyless bit system that is found on higher specification models and is designed for drilling into hard materials such as concrete. |
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| Gears and torque | ||
| The gears in a drill are like the gears in a car - they are there to transmit power from the motor to the chuck and the drill bit.
For general drilling one gear is adequate and this is usually what the simplest and cheapest drills come with.
If you want to use the drill as a screwdriver it's worth paying extra for the second gear: the first gear offers greater torque (twisting force) at lower speeds giving greater control of the drill when driving screws, whilst the second gear is for drilling with a lower torque but a higher speed. It is possible to buy models with a third gear but these are designed for the professional. Most drills come with five torque settings suitable for tackling the range of materials most amateur DIYers will encounter and a reverse gear useful for undoing screws or freeing stuck drill bits. |
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| Variable speed | |
| The speed of a drill, measured in RPM (revolutions per minute), is important to its overall performance. Single-speed, low-end power drills, will be of limited use with materials of differing toughness. More versatile is a variable speed control, which allows you to match the speed to the job, and material you are working with. For accuracy, it is always wise to start drilling slowly and then gradually increase the speed by squeezing the trigger harder. Drills with 'fast stop' will stop quickly when the trigger is released. This gives you greater control, making for a neater result. | |
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| Hammer action | ||
| Many drills now come with a hammer action setting designed for drilling into heavier and harder materials such as masonry. Drilling into hard materials is made easier by the striking action of 10,000 beats per minute or more - at the same time as they drill. You will need specially toughened tungsten carbide tipped (TCT) masonry bits. | ||
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| Before you buy | ||
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There is a huge range of additional features available but some of the most practical are:
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| Roll over menu items for a quick description of each section. |
| Advantages and disadvantages - what type of drill will be right for me? |
| How much power do I need? |
| A guide to using different types and styles |
| How many do you need? |
| A guide to speed and performance |
| An extra option for even easier drilling |
| A handy checklist to read before you buy |