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| Cordless or corded? |
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| For newcomers to DIY, a cordless drill with rechargeable battery
may be the best option. Though less powerful than corded drills, they are lightweight, easy to handle and safe,
and can be used almost anywhere. For lengthy jobs, a second/spare battery and/or quick charge facility prevents
time being lost waiting for the unit to recharge. More experienced and confident users may appreciate the extra
power and torque of an electric (corded) drill. Suitable for more demanding or frequent use, these mains-powered
drills also offer a number of features not available on most cordless models. |
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| Advantages |
- Flexible and convenient - great for hard to reach places, especially working up ladders, in trees, in the loft or working outside.
- Can also be used as an electric screwdriver, removing the need to manually insert and remove screws.
- No trailing flex to get in the way, so safer to work with.
- Lightweight and easy to handle.
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| Disadvantages |
- You must remember to charge the battery.
- They do not have as much oomph as corded models and may run out of power mid way through a project.
- Some models are not ideal for drilling through masonry.
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| Advantages |
- More oomph.
- Continuous power when you need it.
- Greater power and torque.
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| Disadvantages |
- The cord can be restrictive and sometimes an extension cable will be necessary when working away from a power source.
- Often heavier than cordless models.
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| Power rating |
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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 |
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| 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. |
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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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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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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 |
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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 |
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| 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 |
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| 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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- Pick up the drill and check you can lift it comfortably. Too heavy and you may struggle when drilling overhead. Too light and the drill may be unable to cope with more demanding tasks.
- Is the handle comfortable? If you are left-handed check the drill is comfortable. Look for a rubberized or 'soft grip' anti-slip handle to allow you to maintain a better hold.
- T-shaped handles are usually easier and more comfortable to use because the battery is centered and the drill feels more balanced.
- How long is the life of the battery, how long does it take to recharge and does it have a one hour fast charge facility?
- Is it possible to purchase an additional battery? Are the batteries interchangeable between other power tools of the same brand?
- Does the drill come with any useful extras such as carry case, drills and accessories?
- How long is the guarantee?
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There is a huge range of additional features available but some of the most practical are:
- Magnetic surface on the top of the drill for holding small drill bits, screwdriver bits or screws.
- Integrated spirit level, useful for drilling accurately.
- Automatic shaft arresting - the spindle automatically locks into place when the drill is off, making it easier to turn the chuck.
- Front secondary handle to provide additional control, useful for steadying the drill.
- Depth stop for drilling to a predetermined depth (for example, when using a wall plug).
- Lock on button for greater comfort and ease during lengthy drilling
- Moveable 180 degree head, provides greater access for driving and drilling
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