Drill Bits

A drill is only as good as the drill bit used to do the drilling. There's no point having an expensive multi purpose cordless drill with hammer action, variable speeds, depth gauge, torque control, quick release or keyless chuck and multiple batteries if the drill bit is of inferior quality. It's the part that does all the work. Takes all the punishment dished out by timber or masonry. It's grinds and cuts, get hot, incredibly hot and spews out debris along it's Archimedes screw of a body. The tail of the drill bit which is gripped by the chuck is called the shank. When you lean on the drill body to drive home the bit it takes the strain and bites into the timber with it's precision engineered and beautifully symmetrical steel cutting bit. The head of the bit can often be made wider, for boring larger holes with the narrower shank used to hold it in the drill, this gets around the problem of only being able to drill a whole as wide as the opening on the chuck.

But before we start boring we need to choose the right bit for the job. Try and drill into timber with a masonry bit and you won't get far. Likewise if you try it the other way around. Let's look at the common bits using pictures where possible.

Masonry bits
The flat nose of the bit helps it to grind away the stone. One a hammer action drill the stone is pounded and grinded away.










Twist and centre point drill bits
The flat, blunt nose of these drills can make it difficult to start drilling without wavering off course. Making a small indentation where to middle of the hole should be can sometimes help.

Spade bits
Spade bits are flat with a very precise centre point for accurate drilling and a wide blade for drilling larger holes through timber.

Countersunk bits
You might be familiar with the countersunk screw. The head of the screw is not flat. Instead it looks like a cylindrical pyramid. The countersunk drill bit creates a recessed in the timber to accommodate the head of the screw giving a nice, neat finish.

Cordless drills

With so many options available when it comes to buying a drill it can be daunting trying to decide which drill tool is best for you. The first decision you’ll have to make is if you need or even want the extra power of a a corded, electric, drill, or if the flexibility of a handheld drill is what you need.
When you say the word ‘drill’ to most people, especially those new to DIY, nearly everyone will think of the pistol shaped handheld cordless drill. For most jobs, DIY or professional they are powerful enough. Corded drills can even be too powerful when it comes to using the drill as a screwdriver, delivering so much oommmppphh that it is hard to delicately control the movement of the drill, or screw bit as is required when the screw first bites into the timber. Home assembly of furniture is a widely used application for electric drills these days so being able to screwdrive well is a must for most people and cordless drills are excellent at this giving fine control over the application of power to the screwdriver bit.

Along with the inconvenience of supplying power and running a cable the corded drill is, in most cases, best left to specialised applications that need the extra grunt power. Drilling into masonry or stone for example can often require a powered drill tool depending on the number or depth of holes to be bored. Heavy duty use too, where the drill will be in action all day needs power, although a rapid charger kit and two cordless drill batteries can overcome this deficiency of cordless drills.

There is a third option. The drill press. Fixed to a workbench they give excellent, quick precision but have the obvious drawback of not being able to be moved. I’m not going to dwell on these here but will probably come back to them over to coming months.

We'll look at some of cordless drills on offer (from the big manufacturers) over the next fews posts.

Overview of Drill Tools

Before purchasing any drill tools it is useful to have a good understanding of the components that make up a drill, their correct names and the different features that each component can have. Let's start with a run down on the basic anatomy of a drill and how it works.

Drill Bits
Starting at the end that does the work there is the drill bit. Drill bits used on timber work by slicing thin shavings out of the wood. The rest of the drill bit i.e. the shaft is an augur (or Archemedes screw), a helical shape shape used to carry materials, in this case shavings, out of the hole. Masonry bits work slightly differently to timber bits, crushing the stone or brick as the drill bit rotates. Some drills have a hammer action to aid this crushing process.

Hello Chuck
The drill bit is held in place by the chuck which clamps onto the drill bit and forms part of the body of the drill. Traditionally the chuck was opened using a key. The drill bit was then inserted and the key could be used to close the chuck up and grip the bit tight. This was a time consuming and tedious process but luckily most drills these days have keyless chucks that can be opened and tightened by twisting with your hands. More expensive drills have quick release chucks which can be 'popped' off. The drill bit goes with it when the chuck is removed but if you're swapping between drilling and screwing, say to pre-drill a hardwood timber before screwing into it, then it is much quicker to swap between two quick release chucks. (But not as quick as having two drills!).

Pistols or egg whisks?
Looking at the main body of the drill we can see it's shaped like a pistol. This is the shape we all associate with drills these days but I can remember seeing and using hand powered drills which were more like kitchen whisks in their shape. There's still a certain satisfaction to be had from feeling the hand powered intermeshing cogs pull against each other and hearing the sound of the bit as it rips the timber. But back to pistol drills... Where the chuck connects to the body there's usually a clutch. This ring or dial adjusts the torque or the amount of power applied to rotate the drill bit. There's also a switch to reverse the direction of the rotation of the drill bit, essential when the bit gets stuck.

Powered Drill
Finally we get to the power source. The most convenient drills to use are cordless, battery powered drills. It's often useful to have two batteries. Drills, like all battery powered devices have a tendency to give out at the most inappropriate times. Also a 14v or above battery will have enough power for most DIY jobs. But if you'll be drilling a lot of stone, using a hammer action drill, then a corded drill might be best for you.

We'll take a look at different types of drill tools in more detail over the next few posts.

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Drill Tools

Welcome to Drill Tools! This site provides reviews, tips and techniques for all things drilling. If you want to find out which is the best hand drill or powered drill or if Makita is better than Bosche then stick around for comparisons of drill tools makes and models.