When you’re new to drilling, determining the right drill bit for your project can seem overwhelming. Use our beginner’s guide to essential drill bit types to compare shapes and material compositions, and find the right bit for your needs.

Drill Bit Types Based on Shape

One way to categorize drill bits is based on their shape. Each bit’s geometry affects how it cuts, the holes it creates, and the techniques you must use to drill safely and efficiently.

Twist Bit

The twist bit is the most-used drill bit and is versatile for various applications. It features a spiral-shaped flute that helps remove debris quickly.

Twist bits are suitable for drilling holes in wood, plastic, and metal materials. They are available in various sizes and can be used with handheld drills or drill presses.

Hole Saw

The hole saw drill bit is designed to create large-diameter holes. It consists of a cylindrical attachment with sharp teeth on the rim.

Hole saws are commonly used in woodworking and construction projects for tasks like installing doorknobs, cutting holes for pipes, and creating openings for electrical wiring. They are available in various sizes to create different hole diameters.

Core Bit

Core bits are cylindrical bits that drill large, deep holes in masonry, concrete, and stone. Like hole saws, core bits have a hollow center that allows them to remove a cylindrically shaped core from the drilled material.

Core bits are commonly used in construction and plumbing projects when installing pipes or conduits, or creating holes for ventilation systems. Core drilling requires a tool called a core drill or coring tool.

Spade Bit

Spade bits, also known as paddle bits, are made for drilling larger holes in wood and other soft materials, like plastic. They have a flat, paddle-shaped head with a pointy tip and two cutting spurs. Because of this geometry, the bottom of the hole the spade bit creates is not smooth.

Spade bits are suitable for creating holes for wiring, drilling large-diameter holes for plumbing, and installing door locks. They are generally used in handheld drills and come in different sizes to create different hole diameters.

Step Bit

Step bits are unique drill bits that feature a stepped, conical design. They are primarily used for enlarging existing holes or creating multiple hole sizes with a single bit.

Each step is about a quarter of an inch thick. If you drill past this depth, you will start cutting with the next step and create a larger hole diameter.

Step bits are commonly used in metalworking and electrical projects that require precise hole sizes. They are ideal for drilling holes in materials like sheet metal, plastic, and aluminum.

Drill Bit Types Based on Composition

Drill bits can also be categorized based on their composition. Each material affects how brittle, hard, and durable the bit is.

High-Speed Steel (HSS)

High-speed steel drill bits are the most-used type because they are durable, versatile, and cost-effective. They are made from a combination of steel and other elements, like tungsten.

HSS bits can drill plastic, hardwood, and some metals. They have excellent heat resistance and retain their hardness at high temperatures.

Cobalt

Cobalt drill bits are known for their excellent heat resistance and durability. They are made from a steel blend and contain five to eight percent cobalt, making them suitable for drilling in hard metals such as stainless steel and cast iron.

Cobalt bits retain their sharpness for longer and can withstand high drilling temperatures. They offer greater durability and performance than standard HSS bits.

Carbide

Carbide drill bits are the hardest, most brittle drill bits. They are made from tungsten carbide and often contain other materials, like cobalt. You can choose between solid carbide bits and carbide-tipped drill bits.

Carbide bits are designed for drilling into hard materials, such as cast iron and non-ferrous alloys. Carbide drill bits cut precisely and efficiently, excelling in demanding applications.

While other drill bits cost less, the remarkable performance and exceptional durability of carbide bits make them a worthwhile investment in industrial settings. Save time, reduce the cost per drilled hole, and get a burr-free finish with carbide drill bits.

Drill Bit Coatings

Coatings are another available feature of drill bits, and they help extend each tool’s service life. The three most common drill bit coatings are titanium nitride coating (TiN), titanium carbon nitride coating (TiCN), and titanium aluminum nitride coating (TiAlN).

TiN coatings are made with a compound consisting of titanium and nitrogen. This is a great general-purpose coating that extends tool life by 2 to 4 times when compared to non-coated drill bits.

TiCN coatings consist of titanium, carbon, and nitrogen, and they can extend tool life by 4 to 5 times. You can apply coolant to control the temperature, then use titanium carbon nitride coated bits to drill abrasive materials, cast iron, copper, and more.

Finally, TiAlN coatings consist of titanium, aluminum, and nitrogen and can extend tool life 4 to 10 times. Titanium aluminum nitride coating is an excellent choice for drilling when high heat is generated.

The Right Drill Bit

This beginner’s guide to essential drill bit types demonstrates that the geometry, composition, and added coatings or treatments will affect each bit’s suitability for a particular project. When shopping for drill bits, consider the following factors:

• Workpiece material: Masonry, metal, plastics, and other materials require different drill bits.
• Required hole size: The wrong drill bit size can result in inaccurate holes or damage to the material.
• Tool compatibility: Some drill bits require tools with higher power levels and specific chuck sizes.
• Drill bit quality and durability: High-quality bits, such as carbide or cobalt, offer superior performance and longevity, reducing the frequency of drill bit replacement.

You can confidently choose the correct drill bit for your project by carefully considering each factor. You can also ask your supplier for more insight into how different drill bits can help you produce quality work.

A selection of high-quality drill bits will make it easier to perform various drilling jobs well. At Drill Bit Warehouse, we carry durable drill bits for general-purpose and specialty work.

Shop our selection of carbide drill bits for sale for tools that cut through extremely hard ferrous materials, cast iron, brass, and more. While carbide drill bits are the hardest on the market, ours are also cryogenically treated to create an even harder tool. Contact us today for more information about any of our drill bits.