Drills, Drivers, & Bits
Hand screwdrivers
Screwdrivers are tools used to drive screws, with many styles and configurations available for purchase. At the most basic level, screwdrivers feature a driver bit that projects from an ergonomic handle. Traditionally, the bit is machined into the shank of the driver, with a set of drivers being composed of many different driver types. These tools are basic in their construction and affordable to buy, with each size and type of drive being useful for its individual applications. Many companies sell sets of these drivers, with a collection of the most common drive types and sizes in one handy case or holder. Owning a set of these to keep in the van is very useful and cost effective and are useful when assembling furniture or fitting mounted components.
More compact and useful ratcheting varieties of screwdriver are available as a modern adaptation of the basic concept. The ends of these drivers feature a magnetic hex slot, capable of receiving any standard hex shanked driver bit. The ratchet can be adjusted to turn clockwise or anticlockwise. Other more expensive varieties feature other improvements such as adjustable handles that can change angle of presentation or be turned perpendicular to the shank to increase the torque of the driver. Whilst screw drivers are not used in modern carpentry as much as other trades, owning a set is still recommended. The advantage that they possess over electric drivers is that one can feel the torque they are exerting through a screwdriver, whereas electric varieties can quickly strip out a screw.
Bit brace
Bit braces are a traditional form of driving tool that have been used in construction for centuries. In recent times the bit brace has been replaced with electric drill drivers, though they still see much use in workshop and joinery applications. These tools have seen many iterations over the past few hundred years, with improvements being made as technology advances. The tool itself features a central “U” shaped metal body, with a few free moving handles for holding. The back of the tool features a spinning wooden knob that can be grasped comfortably in the hand. This knob provides the solid foundation for the effective use of the tool. The other point of registration on this tool is the free spinning handle located at the peak of the “U” shaped body. With the rear knob firmly held in place, and often braced against the body, the other handle is spun, in turn spinning the front chuck. Traditionally this chuck was a simple 2-jawed keyless chuck, capable of receiving the iconic diamond shaped brace bits. As technology advanced, these chucks were replaced with more practical 3-jaw keyless chucks, with many models also being fitted with ratcheting mechanisms. The 3-jaw system allows for the use of hexagonal shanked bits. The relatively large radius at which the body can be spun allows for a fast rate of spin at the business end of the brace. With a sharp bit installed, holes can be effortlessly and effectively drilled through wooden components. Whilst modern electric drill drivers are capable of outputting more torque and faster speeds, the bit brace still sees many practical applications in modern construction. The main advantage they possess over their electric counterparts is the control one has over them. When working on delicate components, such as drilling into the side of doors, it's not so unlikely that the rapid speed and power of an electric drill can get away from oneself, causing damage to the user or the component. With the slower turning speed and increased control of the bit brace, these tools allow for safer and more controlled working practices.
Hand Drill
Hand drills are a form of hand powered, gear driven, drill driver. Whilst these tools have been superseded by faster and more powerful battery powered drill drivers in fast paced modern construction, these tools are by no means obsolete in their use. These drills are intended for smaller driving applications and can be used to great effect in the workshop, as well as being a great addition for general tool kits. The drill features a straight wooden or composite handle that is attached to a metal frame style body. Within the centre of the frame a large gear is located, with a handle attached to the side of it. At the business end of the drill, a keyless chuck is attached to another gear that interlocks with the larger one. When the handle is turned, the chuck spins, with the direction of spin relating to the direction the handle is turned. The three jaw keyless chucks are capable of receiving an array of smaller drill bits, as well as hexagonal shanked driver bits for driving screws. Whilst they are marginally slower than electric drill drivers, the advantage they have is that no electrical power is required. As such, there's never a time when they won't work.
Drill bits
Drill bits are cutting accessories that are used in conjunction with some form of drill in order to bore holes through materials. The basic design of a drill bit sees a cutting head attached to a shank that can be inserted into a drill driver or other driving tool. When spun in a driver, the rotational behaviour of the drill bit cuts or abrades waste from the surface of the material that is being drilled. Many different types of drill bit are available for use with different materials, in order to achieve a variety of criteria. Here is an explanation of the most common styles of drill bits and their intended use.
Shank styles
Amongst the large array of modern drill bits, there are a variety of shank styles that are designed for specific applications and use with different tools. Some shanks styles are designed with a sole application in mind, with others being more universal.
Straight rounded shank
The most common style of drill bit shank, being the most affordable to purchase and most cost effective to manufacture due to the limited machining requirements. The shank projects away from the cutting end of the bit in a straight fashion, typically at the full diameter of the blank that is used to create the bit. This shank can be inserted into common three jaw chucks, though this arrangement relies on the friction of the jaws pinching the shank to hold it in place, as opposed to other positive holds. Smaller rounded shanks can also be chucked up in an older style 2 jaw chuck that is commonly found in bit braces.
Hexagonal impact shank
This style of shank is primarily intended for use with impact drivers, though the hexagonal shape itself was designed to work in conjunction with any 3-jaw chuck. The hexagonal shape of the shank receives into the mouth of the impact driver, with the quick release detent in the shank allowing a spring-loaded ball to retain the shank in the jaw of the impact driver. Whilst primarily found on the common hex shank screw driving bits, most styles of drill bit can be purchased with a hex shank for use in an impact driver, though they are typically a little more expensive. The hexagonal shape of the shank can also be chucked up in a regular 3 jaw chuck, with more security than a regular rounded straight shank. They can also be installed in a 2-jaw chuck with limited success, as aligning them can be difficult.
Square tapered shank
This traditional style of shank was originally designed for use with the traditional style of 2 jaw bit braces. The tapered shape of the shank receives into the serrated jaws of the chuck as it is tightened. The shape of this shank is not suited for use in other modern styles of chucks, though some manufacturers still reproduce them for use with antique bit braces.
SDS (slotted drive shank)
The SDS is a modern shank style most commonly used with masonry drill bits. Special SDS drills have been created for use with this shank style. Hammer drills that are designed to receive this shank style can only use bits that feature this shank style. When the bit is installed, retaining ball bearings lock into elongated alignment grooves in the shank. As such, when secured in the chuck, the bit can still move forwards and backwards slightly, whilst being held captive. This reduces the wear and strain on both the bit and the drill under the heavy percussive forces exerted during use.
Wood bits
In the context of carpentry, it goes without saying that wood bits are the most commonly used and widely available. Here is a rundown of the most utilised styles of wood bits and their intended use.
Brad point bit
The brad point bit is a general-purpose wood bit that is available from most tool and building merchants. The very centre of the cutting end features a sharp point that helps to align the drill bit in the desired drilling location, preventing it from drifting in the bore hole whilst drilling. The main shank features 2 helical flutes that come up to sharp cutting edges at the top of the drill bit, just below the central point. As these edges come into contact with the wood, they score and sever the fibres of the timber, with the waste material being removed from the bore hole via the helical flutes. They are effective for lightweight timber boring applications, especially in the workshop, but can often be brittle and snap easily in heavier duty site applications. That being said, they are cheap to buy and replace. Sizes commonly range from fine 0.5mm diameter bits all the way to around 10mm bits, before they begin to be replaced with heavier duty auger bits. The most common shank style is the straight round style. Some styles can be purchased with an impact hex drive shank, though the impact action of a regular impact driver will easily sheer the bit off.
Spade bit
The spade bit is a very cost-effective boring bit that is used for a range of hole boring applications. The cutting end is a wide flat “spade”, that is the diameter of the hole. Diameters can range all the way to around 50mm, though at this width the bits can be bogged down in the hole with the amount of material to be removed. The top outside corners of the spade feature two sharp points that score the timber to define the outside diameter of the hole. The very centre of the bit also features a long sharp point that is used for locating the bit on the intended drilling point. The shank is most often the hexagonal impact style for use with impact drivers. They can rapidly bore a hole through timber, though the quality of the hole is not necessarily as clean in comparison to other styles of bit like the auger and brad point bits. Modern varieties on the market can feature a threaded centre point that pulls the bits through the timber for rapid hole drilling. Due to this feature, other trades such as electricians and plumbers opt for this style of bit for quickly installing cables and pipes through timber. A sharp and well-maintained set of spade bits are preferable over other type of wood boring bits for boring holes in modern doors, as we’ll look at later. This style of drill bit can be sharpened relatively easily with a file, though they are also cheap to replace.
Auger bit
The auger bit is a style of wood boring bit that is used to great effect in the workshop and on site for heavy duty drilling operations. Traditionally, the bit features a small diameter inner shank, with a single sharpened flute that travels helically around the centre towards a sharp cutting edge at the top of the bit. The very top of the drill bit features a threaded point that helps to pull the drill bit into the wood. The deep flute of the bit is very effective at removing waste material from a deep hole during the boring process. Due to the relatively thin shank in comparison to the diameter of the bit, these bits are typically wider, as the smaller diameters are more susceptible to breaking. These bits can be purchased in a range of standard sizes such as 18mm ¾”, 25mm 1”, and 32mm 1 ¼”. Modern adaptations of these bits see dual or tri-threaded varieties, intended for rapid boring capabilities that match the speed of modern construction. The sharp cutting head of this bit allows for a very clean hole to be bored though finer workpieces. Quality bits of this style are generally more expensive than other styles, though they can also be sharpened relatively easily, reducing the necessity to replace them when blunted. We will look at how these drill bits, along with the other sharpen-able varieties can be sharpened later on in the book.
Forstner bit
The Forstner bit is a wood boring bit designed for drilling large diameter, clean holes. This style of bit is most often found in drill presses or other stabilised drilling machines for the repeated boring process within a workshop environment. The outer diameter of the bit features a sharpened blade that cleanly severs the outer fibres of the wood to create a clean hole. The inner portion of the cutting face features sharpened blades that remove layers of the material as the bit is advanced into the hole.
Combination countersink/drill bit
This style of drill bit is a speciality combination bit that helps to speed up the process of installing screws in finished applications. The shank of the bit is a hexagonal impact style that can fit in both impact and drill drivers. Just above this, a sharpened counterboring assembly is fixed to the shank. The centre of the shank is drilled out to receive a specific diameter of wood drilling bit, often a small brad point. The bit is held securely in place with a set screw that can be undone via Allen key or flat head driver, to allow replacement of the bit in the event it snaps. When drilled into timber, the pilot brad point bit drills a hole to receive a screw, with the countersink bit counterboring an appropriate slot for the head of the screw. This saves time and is more efficient, reducing the number of actions to be performed for the installation of each screw.
Centre finding bit
The centre finding bit is a specialist wood drilling bit that is designed to drill centred holes for ironmongery. The mechanism often features a hexagonal impact shank that can be chucked into a 3-jaw chuck or used in an impact driver. The end of the bit features a spring loaded, rounded sleeve that covers a smaller inner wood drilling bit. The rounded sleeve can be placed in a countersunk hinge or latch hole, and the bit will centre itself. The trigger of the drill can then be pressed, plunging the drill bit out the end of the sleeve and drilling a perfectly centred hole in the middle of the desired location. This is useful for accurately drilling pilot holes for ironmongery.
Non-wood bits
Alongside this selection of wood drill bits, there are a handful of alternative drill bits that are used for boring holes in other materials. These drill bits are fairly common on site for the non-carpentry related applications. Here is a rundown of the most common types and their features.
HSS (High Speed Steel) Metal bits
HSS bits are hardened drill bits that are intended for drilling holes through metal, though they can also be used to drill holes into softer materials like timber also. The drill bits feature a slight point for aligning the bit, though they are not necessarily sharp like a wood bit. The two flutes of the bit allow the shavings of metal to be removed from the hole as the bit cuts. The bits feature hardened edges on the top of the flutes that scrape away the surface of the softer metal that is being drilled.
Step drill
Step drill bits are designed for boring large diameter holes in thin sheet metals. The bit features multiple stepped diameter cutters that remove material incrementally in set diameter intervals. Some styles feature a flute down the edge of the bit to clear the waste material away from the hole as it is being drilled. The bit is made from a hardened metal like most standard metal boring bits.
Masonry bits
Masonry bits are drill bits designed for drilling holes into masonry such as bricks, blocks, and concrete. Smaller diameter bits often feature a straight rounded shank that can be installed in a three-jaw chuck, with larger diameter bits typically featuring an SDS adapter for use in hammer drills. The additional percussive force of the hammer drill function, either from an SDS drill or a hammer drill combination function, aids the bit in boring the hole. Whilst the shank is typically made from hardened steel, an even harder alloy insert is installed in the tip of the drill bit to resist the rough treatment that occurs during the drilling process. These bits can be used to drill through wood also, though the hole is not very clean at all, due to the lack of a physically sharp edge.
Tile and glass bits
Tile and glass bits are specifically designed drill bits that are intended for drilling through tiles and glass. These materials are brittle by nature and typically crack or chip when drilled with other conventional drill bits. These special drill bits feature cutting edges made from alloys such as tungsten carbide, with others that are diamond tipped - drilling holes in these harder materials by eroding the surface with their harder cutting edges.
Additional drill bits
Aside from the primary drilling bits that we’ve looked at, there are also a selection of specialty bits that are for performing niche tasks. Here is a rundown of these most common alternative bits.
Countersinks
Countersinks are special wood bits that are designed for boring shallow holes in timber that match the head contour of regular wood screws. By countersinking a hole in timber before installing a screw, the head of the screw can be wound below the surface of the timber without damaging the surface fibres or pulling too hard on the workpiece. Varieties with depth stops can be purchased to bore consistent depth countersunk holes.
Hole saws
Hole saws are large diameter saws that are intended for boring wide holes in timber or masonry. Both timber and masonry hole saws possess a different construction respectively. The timber hole saws are hollow circular saw blades that feature actual saw teeth for cutting the fibres of the wood. The masonry hole saws feature diamond tipped edges that grind away at the masonry. Both styles are attached to a threaded arbour that can be chucked up in a regular 3 jaw chuck. Larger masonry hole saws may feature an SDS chuck, as the masonry drilling process can be too intense for smaller hand drills. The hollow nature of the hole saws allows large diameter to be bored without drilling or grinding away all of the inner material. Instead, a radius is cut around the waste material until it is separated from the main body of material, at which point the circular waste can be removed easily. Both styles of saw are used for creating holes to allow ducting, pipework, and electrical cables to pass through surfaces such as walls and floors.
Chuck adapters
Chuck adapters are special inserts that are designed to adapt existing chucks to receive alternative styles of shank. For example, a three-jaw chuck with an SDS shank on it can be placed into a hammer drill, allowing regular circular and hexagonal shanks to be installed into an SDS drill. That being said, the increased torque exerted by an SDS in comparison to a hand drill or drill driver can damage bits that are not designed for this application. Adapters can also be purchased for impact drivers that convert them to 3 jaw chucks or SDS chucks.