Cordless drill reviews: Features explained
Drill features explained on video
Learn about batteries, chucks, hammer-drilling and torque-settings
DIY and drilling expert Roger Bisby takes us on a tour of his drill to explain the key features to look out for when buying a drill, including battery-weight, types of chuck, rotary and hammer drilling and torque settings. Watch our video below to find out more about cordless drills.
Types of cordless drill
Combination drills combine high-speed rotary drilling, screwdriving and hammer drilling. It’s the hammer drilling that helps to set combination drills apart from other cordless drills and drill drivers. It also means they can be put to work on very hard surfaces that cordless rotary drills can’t handle.
Hammer mode: This lets you drill into hard materials such as concrete. Rotary drilling is supplemented by a hammer action, which allows the drill bit to strike the surface thousands of times a minute and puncture extremely hard and dense surfaces. Use tungsten carbide-tipped drill bits when hammer drilling.
Rotary drilling mode: When drilling into metal or wood, set your combination drill to this mode. It provides the high-speed drilling needed for surfaces like this. When drilling through wood or metal, you won’t need to use hammer mode.
Screwdriver mode: Cordless hammer drills also come with a low-speed screwdriver mode. This provides lower speeds, with more torque, or twisting force.
Cordless drill drivers can be used for high-speed rotary drilling for most jobs around the home, such as drilling in wood, interior walls and metal.
Look for a drill with more than one gear. Most drills have two gears now. The first gear gives low speeds and higher torque (twisting force) for screwdriving, the second gives higher speeds for rotary drilling. If a drill only has one gear, it’s unlikely to be able to be successful at both drilling and screwdriving.
Cordless drills come with variable torque settings – handy when using the drill in screwdriver mode. Get the torque setting right, and the clutch will disengage the drill motor when the screw is flush with the surface being screwed into. The torque setting you need will depend on how hard the surface you’re driving screws into is.
The chuck is the part of the drill that holds the drill bit. Most chucks are now keyless and drill bits are attached and removed simply by twisting the chuck. If you have an older drill, it’s likely to come with a chuck key. Make sure you keep this in a safe place, preferably with the drill – without it, you’ll struggle to remove or safely attach drill bits.
Lithium-ion (Li-Ion) batteries are becoming more common and provide the best energy storage available for cordless drills. Nickel Cadmium (NiCd) batteries don’t offer the energy storage capacity of Li-Ion.
This can vary dramatically between drills. In our tests, we found that the very best drills we tested can drill more than 100 holes in sandstone on a single charge. The worst can manage only around 30.
Spare batteries for drills
If you buy a cordless drill, either a combination drill with hammer action or a drill driver, it’s a good idea to buy one that comes with two batteries. If the drill you’re looking to buy only comes with one, consider buying a spare.
If your second battery is charging while you’re drilling, you won’t have to stop work if your battery runs out of charge mid-job.
Rotary drills are ideal for basic DIY tasks, such as drilling holes to hang pictures. They rely on fast rotation (around 3,000rpm) so are best for small holes or on softer materials such as wood, metal or plastic.
Percussion drills rotate at around 3,000 revs per minute (rpm) but for more power their hammer action pounds the turning drill bit at around 40,000 blows a minute.
Simple DIY jobs, and softer stone such as limestone or light concrete, are no problem. Hard stone, such as granite, produces strong vibration and noise because you need to push harder to activate the hammer action.
Most percussion drills have one gear but two gears give better screwdriving control.
Hammer drills are best for sustained or heavy-duty drilling in hard materials, such as granite or very hard concrete. They have a pneumatic action, giving around 5,000 blows a minute to the rotating bit. This provides most of the force, so high speed isn't necessary.
For light jobs, with no hammer function, they're slow and can be awkward to handle. Chisel attachments can be added for removing lumps of masonry.