The modern variable-speed drill is a versatile power tool. Most of them have a reversing motor making it possible to use them as a screwdriver as well. With a cordless drill/driver you are no longer limited by the length of the power cord. A keyless chuck makes it easy to change bits quickly. Modern drills have convenient features such as a magnetic bit holder and a built-in LED light.

Despite all the impressive features of the drill/driver you still need to know a little bit about drilling techniques. But first you need the right drill bits. Today you have accessories that can turn your drill into a grinder or sander, just two mention two possibilities. But for drilling, you need a set of standard high speed steel (HSS) twist bits. These can be used both for wood and metal. If you are going to drill in really hard materials such as concrete and masonry materials, you need harder drill bits. But for most tasks around the house, HSS bits will do. You can get good HSS bits at reasonable prices, harder drill bits tend to be much more expensive.

If you are going to drill large holes in wood, you need spade bits. If you are going to use your drill as a screwdriver, you need a magnetic bit holder plus some Pozidriv, Philips and slotted bits.

The two main things to get right are drilling speed and the amount of pressure to exert, known as the feed pressure. As a rule of thumb, the larger the hole and the harder the material, the slower the speed you should use. Another old rule of thumb says, use slow drilling speed when working with hard material and use fast drilling speed when working with soft material. Also remember to lift the drill frequently, to clear the flutes of the drill bit and to increase air flow. It is often a good idea to create a small indentation before drilling to guide the bit’s initial cut and prevent it from spinning out of control.

When drilling through wood, always be careful to prevent the drill from splintering the exit hole. Most people put a piece of scrap wood behind so that any splintering occurs on the scrap wood. If you don’t have any scrap wood, you can slow done just before you break through the wood and stop once the tip of the drill bit emerges on the other side. Now, carefully drill from the backside, guided by the small hole that the tip of the drill bit created.

When drilling in metal, patience is often required. First, make an indentation so the drill bit does not slip. Of course, make sure that the drill bit can handle the metal before you start. Then hold the drill steady and drill slowly. You also need to lift the drill frequently. Just take your time and don’t lose your patience. Note that the metal slivers can be very hot so goggles are very important.

The battery in your cordless drill is very important. A good battery makes life much easier, you get a powerful drill and can work a lot before the battery needs to be charged. Poor batteries on the other hand don’t last long and may still take a long time to charge.

Today, you have three main types of batteries to choose from. They are:

• Nickel Cadmium (NiCd or NiCad)
• Nickel Metal Hydride (NiMH)
• Lithium Ion (Li-Ion)

Nickel Cadmium batteries were the first batteries to be used in cordless drills and they are still used today. They are relatively cheap and can be charged many times, up to 1,000 times. Additionally, they can be charged quickly, although not as quickly as Li-Ion batteries, and Ni-Cad batteries are less sensitive to temperature than NiMH. The latter means that they can be used in both cold and hot environments. But if the battery itself is hot, charging can become a problem. The main drawback is that they are toxic. Cadmium is a heavy metal that needs to be recycled properly. Ni-Cad batteries also have memory effect problems. Note that Ni-Cad batteries are banned in EU.

Nickel Metal Hydride batteries are newer than Ni-Cad batteries. Compared with Ni-Cad they have higher capacity and are less toxic. NiMH batteries have memory effect problems but less so than Ni-Cad batteries. But NiMH batteries can not be recharged as often as Ni-Cad batteries. They also have higher self-discharge rate than Nickel Cadmium batteries. The self-discharge is generally 30% per month or more, compared to 10% for Ni-Cad batteries and between 5-10% for Li-Ion batteries.

Lithium-ion batteries are the newest of the three main battery types. Lithium is light-weight and possesses very good electrochemical characteristics. But it is an unstable metal, for safety reasons pure lithium is not used in batteries. For most purposes, Li-Ion batteries are the best but also the most expensive. They have the highest capacity, are light-weight, no memory effect and low self-discharge rate. The life time of Li-ion batteries is about three to five years, regardless of how much they are utilized. As expected, most high-end tools are using Li-Ion batteries. If you are going to use your drill a lot, paying extra for the powerful but light-weight Li-Ion batteries is well worth considering. The Li-Ion batteries are also considered to be environmentally safe.

Ni-Cad and MiNH batteries suffer from memory effect. It refers to the fact that batteries have lost their maximum capacity after being repeatedly recharged before the battery was flat. For some unknown reason, the batteries seem to remember the smaller capacity and forgotten the original capacity. Note that Li-Ion batteries have no memory effect. Also note that memory effect has nothing to do with the age of the battery. All rechargeable batteries will lose storing capacity over time, due to secondary chemical reactions within the battery.

Batteries have an Amp Hour (AmH) rating.  It indicates how much energy can be stored in the battery, thus measuring the capacity of the battery. It is the current flow, in Ampere, multiplied by the time of discharge, in hours. If a battery is rated at 20 AmpH, it can sustain a 1 Ampere draw for 20 hours. Just bear in mind that the listed AmH for different batteries may not have been measured in the same way, so higher AmH does not guarantee that the battery is better.

Fast battery chargers are very handy, not just for professionals. If you are using power tools for longer periods, a rapid battery charger makes it possible to work all day with just two batteries. The modern rapid charger charge batteries in 30 minutes or less. But several companies are working on much faster charging times, just a few seconds may be enough for charging batteries in the future.

It was not a long ago when rechargeable batteries were almost useless. Even you charged them according to the recommendations, it generally did not take long before they lost most of their power. Charging the batteries required a lot of time and as mentioned, the batteries generally had to be replaced fairly soon. But with the success of cordless devices, battery technology has improved a lot lately. Even better, prices have fallen as well.

Lithium-ion batteries are powerful and have very few shortcomings compared with earlier rechargeable battery types. And with the rapid 30-minute fast chargers, you generally only need two batteries to keep you covered. Additionally, lithium-ion batteries can be charges thousands of times without losing much of their initial capacity.

But not everyone is happy. Especially smartphones with their large displays are draining their batteries quickly. And while it is not really inconvenient to change the batteries of a cordless drill, you don’t want to keep on changing or charging the batteries of your smartphone all the time. So a solution is needed.

One very interesting potential solution is superfast chargers, charging the batteries a hundred times faster than current chargers. It is actually not the charger that is important, the batteries need to have the right internal structure. In theory, it is possible to charge lithium-ion batteries in a minute or two. It is actually relatively easy to construct such a solution on paper. The real problem is to find a way of producing such batteries in a cheap and reliable way.

A number of projects are trying to find a solution that can be commercialized. The market is huge, power tools would be a relatively small market compared with smartphones and laptops.

How fast a battery can be charge is primarily limited by the movement of electrons into the cathode. But one of the main problems is that fast charge times generally mean less capacity. If you decrease the charge time, you also end up with a weak battery. If you want a powerful battery, the charge time increases. As mentioned, there are solutions to this but the real problem is to find a way of producing reliable batteries in large quantities, to reasonable prices.

Cordless drills have become very popular, nowadays they are cheap and powerful. The early cordless drills were not very powerful and the battery did not last very long. Things have changed a lot since the early days, nowadays cordless drills are generally superior to mains powered drills. But for some people, a cordless drill may not be the right solution. Here is an overview of the cordless drill vs. corded drill topic.

An electric drill is the most useful power tool, every now and when you need one. The good old corded drill is cheap but nowadays a cordless drill can be a better choice. For many professionals, cordless drills are the best choice. A cordless drills is not limited by the cord and is suitable for most tasks. By having two batteries, the drill can be used non-stop. Once the battery is flat, replace it and charge it in a fast charger. It will be charged before the other battery is flat. Thanks to the fast chargers, batteries can be charged in less than 30 minutes.

But if you are only using your drill once in a while, then you may find that the battery is flat even if you haven’t used the drill. Self-discharge is still a problem. Most batteries have a self-discharge of about 10% per month. Also, batteries don’t have unlimited lifespan. With a corded drill, you don’t have such problems.

A good cordless drill can be used as a hammer drill as well as a screwdriver. If you buy a drill with hammering action, you can drill holes in concrete. Hammer drills have a switch that enables the hammering action, so they can be used as standard drills. The hammering action will damage softer materials. If you are going to use your drill has a screwdriver, it should have a reversing switch which changes the direction of the rotation. This makes it possible to drive and remove screws. The drill also needs to support slow speeds and preferably have an adjustable slip-clutch mechanism. This prevents the drill from damaging the screw or the workpiece.

Despite that cordless drills have a battery, they typically weight a little bit less than corded drills. But cordless drills are more expensive. So if you are seldom using a drill, a cheap mains powered model may be the best choice for you. Note that if you need a drill with hammering action, i.e. a hammer drill, you may prefer corded hammer drill. The hammering action drains the battery quickly. But apart from the problem with the energy-consuming hammering action, a cordless drills is a very versatile tool and nowadays relatively cheap. In most cases, a Ni-Cad drill is the best budget solution while a lithium-ion drill is the best choice if you need a powerful cordless drill. Ni-Cad batteries are heavier, bulkier and less powerful than the more expensive lithium-ion batteries.