While this guide to drill bits focuses on the various aspects and types of drill bits, you are encouraged to purchase a drill bit kit. I’m suggesting that from hard-won experience because you never know when you will need that one drill bit you never thought you would use.
It happened about six years ago, that friends of mine and I were building a cabin in the woods on the side of a mountain by one of the largest lakes in the US. Remote did not begin to describe it.
We were using a portable gas generator to run the power tools, lashing together the pre-built modules we’d hauled there in a trailer.
As we worked, we realized we would need a hole through the floor large enough for the all-weather extension cord to plug into the generator. That was the moment, 72 miles from the nearest major city, that my friend realized he did not have a drill bit big enough.
He’d bought individual drill bits through the years as he needed them and, of course, none were the appropriate size for this because he had never needed to drill anything that large before.
The moral of this story is to purchase a full drill bit kit. You will need more than one size. You will someday need a drill bit you never imagined you would require. Let’s hope you do not have it occur more than 70 miles from the nearest major hardware store.
Therein lies the catalyst for this – the ultimate drill bit buying guide. This examines the size of the various bits, functions, materials from which they’re crafted, some of the best drill bit kits and where to purchase drill bits.
I hope you never need the one bit you do not own and that this buyer’s guide can help you find the right drill bit kit for you.
Related: Types of Drills | Types of Power Tools | Types of Tools | Woodworking Projects that Sell
Different Types of Drill Bits and Their Uses
Types of Drill Bits by Size
The range of sizes of bits varies vastly. You will find about 47 standard sizes. Drill bits go up to two-inch bits, but they do make larger.
Check out this drill bit size chart (it’s mind-blowingly detailed).
Expressed in decimal inch measurements the standard drill bit measurements range from .1250 to .3110.
You might think a chart goes a bit over the top, but not really. You see, drill bits do not have a standard naming convention. Some manufacturers letter them, some use metric measurement, some use inches, others use a numeric naming convention that could be considered rather arbitrary.
Here’s an example:
an 80 drill bit is also an “O” bit that measures a decimal mm size .0135, also known as a 1/8-inch bit, also expressed as a decimal .1250 in inches. Confused yet?
The chart saves you time and money. You probably do not know offhand that the “O” bit the assembly instructions for your new something or other refers to the 1/8-inch drill bit you already own. The chart is not an overkill.
Types of Drill Bits by Purpose/Function
If you just began doing home repairs or do-it-yourself (DIY) repairs, you will probably experience a bit of shock at the plethora of drill bits. Each major type of material requires a different drill bit.
High-Speed Drill Bits
You’ve probably seen and maybe used a high-speed drill bit, also known as a twist bit. You know that piece of metal that resembles corkscrew pasta? That metal rotini is a high-speed drill bit.
It proves handy for drilling small holes in wood and walls. The flutes in the design channel sawdust away from the hole.
Brad Point Bits
When you need to control the depth and create an ultra-precise, clean hole, use a Brad point bit. They feature rubber stoppers that let you select a depth point. Their precision means they often get used in woodworking projects.
On brick, concrete, and stone, use masonry bits. As tough as these bits are made, you have to replace them relatively often because they wear down.
If you need to drill into concrete with one for long enough, it can cause the tip to melt. You can alleviate that problem by periodically lifting the drill from the concrete to let it rest.
Unless you just got a job on a professional construction team, you probably won’t use a rivet bit. This hyper-specialized tool is crafted specifically to drill short rivets into thin sheet metal pieces.
Use a spade bit to make a rough-cut hole you will never see like those in a joist. Typically, these holes are to facilitate running cables. These do not cut pretty, precise holes.
They have a crude, paddle-shaped tip that easily bores into softwoods. Do not confuse this with an installer bit. It takes its name from its design – a flat blade with a sharp point that resembles a digging spade.
Use this specialized twist bit to drill holes to install wiring for security systems and entertainment. Like auger bits, these can be up to 18 inches long. You can drill through plaster, wood and some masonry using them.
The tip of the bit features a small hole. After drilling the hole in the surface, you insert the wire you need to run into the tip’s hole and push it through the hole. Grasp it from the opposite side and pull it through.
If you need to drill into sheet metal, you need a step drill bit. It’s shaped a bit like a descending staircase. Their versatility costs a bit more than other drill bits, but if you work with sheet metal regularly, you need this.
The stepped design of this bit lets you drill holes of various diameters. Another nifty thing these bits do is de-burr holes, so you can clear waste material.
Use auger bits to drill into thick, dry wood really easily. They drill like slicing butter, so you do not have to apply much pressure. These feature a screw tip that starts the hole and serves to pull the bit through. This results in a clean hole.
You can use these on thick pieces of wood since many of these bits come in lengths up to 18 inches. Large flutes in its design help channel sawdust away from the hole. Some come with a hollow center which allows even more chip removal. This lets you bore deeper.
Use a self-feed bit to drill into the wood when you need a compact bit. It has a screw tip that helps better position the bit and moves it through the workpiece. It doesn’t have the standard flutes of a twist bit, so you need to pull the bit back periodically to clear away chips and dust.
Use a Forstner bit to create clean, smooth holes in wood, especially those that will receive dowels. A Forstner bit gives you a neatly cut exit hole. You can also overlap holes. Its pointed tip assists you in positioning the bit exactly where you need it.
This has no flutes and you will need to pull it out regularly to clean off chips and dust. Many applications require a drill press with this type of bit.
Use a hole saw to drill the big holes required to install door hardware or make a wiring pass-through. The hole saw makes a waste plug and a side cut-out in the saw cylinder lets you push it out.
You can attach these to an arbor or mandrel to use a pilot bit for centering the hole and steadying the blade. Smaller hole saws may include a built-in shank instead of a pilot bit.
There are multiple types of hole saw. Use a bi-metal hole saw to bore into wood and metal. Use a carbide edged hole saw to bore into masonry and ceramic tile. Use a diamond-edged hole saw to drill more quickly into tile and masonry.
Use a countersink bit, also known as a screw pilot bit, to drill into wood. This type can drill pilot, countersink and counterbore holes all at once. You can countersink a fastener, then install a plug over it.
Use a plug cutter to bore holes in wood that simultaneously cut the wood plugs you need to conceal recessed fasteners. This helps you do woodworking that approaches professional-grade work, such as the bookcases you would purchase in a furniture store.
A tile bit uses a carbide tip to drill into some types of the tile while reducing the chance of chips and cracks. Check the packaging to determine the tile it can drill.
Adjustable Wood Bit
Also known as an Expansive Wood Bit, the Adjustable Wood Bit is used to create a variety of holes and uncommon bit sizes, taking away the need for bits of various sizes.
Also known as a Core Drill Bit, the Annular Cutter is used to cut a hole in such a way that the core of the material is left intact and then to retrieve the core from the material.
Bit for Metal
Bits for metal cuts through steel, are designed for heavy-duty work, and the most expensive of the drill bits.
Chain Saw Blade
Its sharp teeth are used for cutting wood and is a key component of a chainsaw.
Crown Tooth Fret Saw Blade
The Crown Tooth Fret Saw Blade cuts through plastic, in both stroke directions, and used for specialized projects that require smoother finishes.
Flat Top Grind Saw Blade
A durable, long-lasting, general-purpose blade used for fast ripping and efficient cuts along the grain.
Glass and Tile Bit
The Glass and Tile Bit is used for drilling through glass, tiles, plastic, composite, brick, marble, and hollow brick. It has better resistance to high temperatures, ideal for drilling through deep materials, and speed up dust extraction.
The Hammer Bit is used to cut through a precise test hole in a concrete slab which is necessary for a complete and accurate relative humidity concrete testing.
High-Speed Cut-Off Wheel
The High-Speed Cut-Off Wheel is used for cutting stone, concrete, structural steel, brick, solids, pipes, and tubing. The disc is used on portable high-speed petrol/gas-driven saws.
Plywood Saw Blade
The Plywood Saw Blade is designed to make smooth rip cuts in plywood and crosscuts.
Reverse Skip Tooth Fret Saw Blade
The Reverse Skip Tooth Fret Saw Blade is used for cutting plywood. The design of the teeth prevents tear-outs or splinters on the bottom of the cut. This blade is also good for beginning scrollers.
Rip Saw Blade
The Rip Saw Blade is used for ripping through hardwood and softwood with minimum effort and minimal scoring.
Segmented Diamond Cutting Wheel
The Segmented Diamond Cutting Wheel is durable, long-lasting, and can be used for a wide range of wet and dry cutting applications.
It cuts through concrete, asphalt, block, brick, marble and granite slabs, and other building materials. It is typically used with concrete saws, circular saws, and masonry saws.
Standard Fret Saw Blade
The Standard Fret Saw Blade is used to clear off sawdust as you cut and is a good beginner blade for scrolling.
Spiral Fret Saw Blade
The Spiral Fret Saw Blade is used for intricate and more detailed projects. It can cut through larger projects in smaller saws and cut in multiple directions so there’s no more need to turn the project.
The T-Slot Cutter is used for milling T-slots into tables and beds of machine tools and whenever a good surface finish is required.
Tip: The bigger the drill bit, the more torque it creates while spinning. You need to clamp down your workpiece with larger bits so you do not lose control of the drill or the workpiece. This is especially the case with Forstner bits and hole saws.
Types of Drill Bits by Material
Drill bits come in many various material designs. Steel bits are very common, as are carbides. The material of the bit depends on the application of the drilling.
Low-carbon steel bits prove most common because they cost the least. They hold an edge poorly and you must frequently sharpen them. You can only use these with wood projects. Even then, you are limited to softwoods because the hardwoods wear down the bits so quickly.
High-carbon steel bits provide a heartier boring. They can overheat from friction during drilling. This results in a soft cutting edge. These steel bits work on wood or metal.
The heat resistant, hard high-speed steel (HSS) tool steel bits can drill into hardwood, metal, and most other materials. They work faster than carbon-steel bits.
Cobalt steel alloy bits contain more cobalt than high-speed steel bits. They withstand higher temperatures better. You can use them to drill hard materials such as stainless steel. They are more brittle than high-speed steel though.
Use tungsten carbide and other carbide bits when you need an extremely hard, tough drill bit that can go through nearly all materials. It can hold an edge longer than other bits.
They are more brittle than other steels and typically only get used for drill-bit tips. The material costs more but is a required bit type in job shops.
Virtually the toughest tool material out there is a polycrystalline diamond (PCD). This tough bit does not wear down easily. Comprised of a layer of diamond particles, 0.5 mm (0.020 of an inch) thick, it bonds as a sintered mass to tungsten-carbide.
These bits typically get used in aerospace, automotive and other industries. Use them to drill aluminum alloys, other abrasive materials and carbon-fiber-reinforced plastics, but not on ferrous metals.
Common Drill Bit Coatings
Even with tougher drill bit materials like high-speed steel, some applications require a coating on the bit. The most common of these include:
- diamond-coated bits for drilling into glass,
- black oxide coats bits to enhance heat resistance, corrosion resistance and lubricity,
- titanium nitride coated bits are typically a twist high-speed steel bit and the substance extends the cutting life by three times,
- titanium aluminum nitride coating extends tool life by five times,
- titanium carbon nitride functions similarly to titanium nitride,
- diamond powder coating helps a drill bit handle abrasive materials such as tile, and stone,
- zirconium nitride coating adds strength.
Three Best Drill Bit Kits
If you are new to drill bit shopping or accustomed to purchasing a single bit at a time, this guide should help you jump start your shopping experience.
The following kits represent the three best that Amazon has to offer based on customer reviews. These represent one of each of the main types of kits, so whether you need an HSS kit or to cut masonry, there is an option for you.
You won’t find yourself without the right bit if you purchase this 100-piece screwdriver and drill bit set. This includes 30 Dewalt Impact Ready FlexTorq screwdriver bits for use in both impact drivers and drills. It also includes 14 pieces of Dewalt gold ferrous Pilot Point drill bits.
These produce accurate, clean holes and breakthrough cleanly. The other 56 heat-treated screwdriver bits come with a compact magnetic drive guide. A heavy-duty magnet keeps the bits in the drive guide and a bit retention system secures them.
This seven-piece Bosch drill bit set provides a patent-pending, optimized four-flute design. It reduces wear on the bit while drilling and keeps the bit cooler while drilling. These carbide-tipped bit heads can handle masonry and other hard materials.
Their durability results in longer tool life. The entire set handles heavy-duty drilling applications like blocks, bricks, and concrete. Built-in wear marks show when the bits wear out beyond ANSI specification. The included storage case makes it simple to organize and transport them.
If you need a high-speed steel set of drill bits, try this 29-piece ultra dex set premium high-speed steel heavy-duty 135-degree split point bits.
From 1/16 to 1/2 by 64ths this Ultra-Dex bit set includes precision-ground points, flutes, and body for accurate hole boring. Crafted at Viking Drill and Tool, the materials used in this set meet National Aerospace Standard (NAS) 907, the most stringent industry standard.
Where to Buy Drill Bit Sets
The beauty of the Internet is that if one store runs out of an item, tons of others exist where you can easily obtain it. This is true for drill bit sets, too.
You can not only purchase these on Amazon but also on the e-commerce sites for Home Depot, Lowe’s, Best Buy, Walmart and Harbor Freight Tools. You can have them shipped directly to your door no matter where you live or work.