Drilling bits or tools are required for drilling machines to make holes in materials. These tools are end-cutting tools designed for producing holes in a workpiece. The machine is said to be applied in different fields and to various materials such as wood, metal, and rock.
Drilling tools vary widely, as they are designed to accommodate the properties of the workpiece and the radius and depth of the desired hole.
This shows that different construction companies use drilling machines. They are made of various types, suitable for specific operations. Drilling tools are used to achieve different operations, and there are other types of drill bits for different holes. In this reading, we’ll explore what a drill bit is, its parts and diagram, types, construction, materials, and coating.
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Learn about drilling with this detailed guide!
What is a Drill Bit?
Drill bits are essential tools for drilling holes in common materials such as wood, metal, plastic, ceramic tile, porcelain, and concrete. These tools come in various sizes and shapes, with each having a unique tip but having similar parts. They are designed for various materials, including steel, aluminum, copper, cast iron, sheet metal, fiberglass, brick, and vinyl flooring.
Drill bits are sized for their diameter and are constructed in various styles to help with specific tasks. Common materials include sheet metal, ceramic tile, porcelain, and concrete. Each drill bit has its own unique tip, but they share the same parts with little or no difference. The various components of a drill bit are body, point, shank, tang, flutes, land, body clearance, neck, and web.
Drill Bit Construction, Materials and Coating
Power drills consist of two key components: the shank and the chuck. The shank is the end of the drill bit that fits into the drill and is secured by the chuck. Round shanks center the bit more accurately, while hex shanks have flat surfaces for a more secure grip.
SDS shanks are used for concrete drills and demolition bits, specifically with SDS-Plus and SDS-Max rotary hammer drills. The chuck is the part of the drill that attaches the drill bit, typically 3/8-inch or 1/2-inch in most home-use power drills. Larger chucks are typically used on heavy-duty and industrial power drills and drill presses.
Drill bits are a crucial tool in various industries, primarily made from high-speed steel (HSS) materials. These bits are suitable for drilling wood, light metals, fiberglass, and PVC. Black oxide-coated drill bits are durable and resistant to rust, making them ideal for hardwood, softwood, PVC, fiberglass, and steel.
Titanium-coated drill bits have reduced friction, require less effort, and last longer than black oxide-coated bits. Cobalt drill bits are ideal for drilling hard metal and steel, as they dissipate heat quickly and are highly resistant to abrasions. Carbide-tipped drill bits are used for concrete, tile, and masonry, while bi-metal drill bits are suitable for light metal, wood, and PVC.
Diamond drill bits are ideal for cutting into glass, sea glass, fused glass, rocks, and minerals. Alloy steel drill bits are commonly used in machine shops for cutting sheet metal of varying thicknesses, making them ideal for working exclusively with thin materials.
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Coating
Drill bits are coated with various materials, including black oxide, bronze oxide, and titanium nitride. Black oxide is the most economical coating, providing corrosion protection, increased tempering, and stress-relieving properties. It is suitable for drilling iron and steel but not aluminum, magnesium, or similar materials.
Bronze oxide is used to visually identify cobalt steel or better grades of high-speed steel. Tin oxide, a more expensive coating, increases the hardness of the bit and provides a thermal barrier, increasing production rates and tool life in harder materials. Tin-coated bits are suitable for drilling iron, steel, aluminum, magnesium, and other materials.
Diagram
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Names of 20 Kinds of Drill Bits
below are the names of different kinds of drill bits.
- Twist Drill Bit
- Brad Point Drill Bit
- Masonry Drill Bit
- Rivet Drill Bit
- Spade Drill Bit
- Installer Drill Bit
- Step Drill Bit
- Auger Drill Bit
- Self-Feed Drill Bit
- Forstner Drill Bit
- Hole Saw Drill Bit
- Countersink Drill Bit
- Plug Cutter
- Tile drill bits
- Adjustable Wood Drill bits
- Annular Cutter
- Bits for Metal
- Glass and Tile Drill bits
- Hammer Drill bits
- Bullet Point Drill bits
Types of Drill Bits
The various drilling tools are flat or spade drills, straight-fluted drill tools, twist drill tools, taper shank core drills, oil tube drills, and center drills.
Twist Drill Tools
These drilling tools are the most common and are frequently used today. They are created using steel that was twisted and then honing the surface. The modern ones are made by machining two spiral flutes that run longitudinally around the body of the drill.
Parallel shank, parallel stub shank, parallel long shank, and taper shank are the four classifications of a twist drill.
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Flat or Spade Drill
A flat or spade drill is often put to use when a twist drill is not available. It is a forged circular tool steel with a cutting edge that ranges from 90 to 120 degrees with a relief at the front ranging from 3 to 8 degrees.
Straight Fluted Drill
The straight fluted drilling tool is often used when drilling brass, as it drills perfectly. It is used because it does not advance more quickly than the recommended feed, like that of a twist drill.
The drilling tool has flutes or grooves that are perpendicular to the drill axis and it is often used to drill softer materials like copper and brass.
Taper Shank Core Drill
The drilling tools are designed to enlarge existing holes that are punched, drilled, or cored. Taper shank core drill cannot create a hole in a solid substance due to the cutting edges that are machined at the center of the drill.
The metal or material is removed with the chamfered edge at the tip of each flute. These drill tools produce better finished holes than those of two-fluted drills. They are sometimes used to create a hole that is half the needed size with three or four fluted drills to complete the drills.
Oil Tube Drill
The oil tube drill is the process where earth-drilling machines are used to bore oil tubes from the earth’s surface to form an oil well. The drilling tools are only used for the purpose.
Centre Drill
The center drill is used to drill center holes into the end of a workpiece. It is a twist drill with a straight shank and two flutes that is used. They drill the holes in precise dimensions.
Titanium Nitride Drill Bits
These kinds of drill bits are coated with titanium nitride. They are hard, fast, and suitable for drilling soft and hard materials. They are suitable in wide industrial applications due to their properties. However, the cutting edge cannot be restored when it wears off unless the coating is reapplied.
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Titanium Carbonitride Drill Bits
The type is similar to that of a nitride drill bit, but they are slippery with a characteristic blue or purple color. Although they have superior hardness, which is why they specialize in drilling hard materials.
Titanium Aluminum Nitride Drill Bits
These kinds of drill bits are suitable for drilling stainless steel, steel, and materials of high temperature due to their high stability.
Black Oxide Drill Bits
The black oxide drill bits make use of inexpensive coating on high-speed steel, making them heat-resistant, frictionless, rust, and corrosion-resistant. They are suitable for drilling PVC, steel, maple, nylon, etc. and they are known as the best general-purpose drill bits.
Diamond Drill Bits
Diamond drill bits are the hardest kinds of drilling tools because they are coated in diamonds. They are suitable for drilling hard material such as metals or rock. Due to their high accuracy, they are suitable for material such as glass, sea glass, etc.
Step Drill Bit
These kinds of drill bits are custom-made, having a conical shape and a running flute that can be straight or angled. This flute help remove the chips from the drilling surfaces. Step drill bits are suitable for drilling soft materials like aluminum and they are vary expensive because they are custom-made.
Unibits
The unibits are similar to step drill bits but have a straight running flute. They are used in hole enlarging and the flute help remove the chips during drilling. They are often used in sheet metal fabrication and drilling soft materials like plywood.
Hole Saw Drill Bit
These kinds of drill bits have short, open cylinders with saw teeth on the edge. They are used in drilling through thin materials such as wood and sheet metals.
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How to Choose a Drill Bit
To choose a basic drill bit, start by learning how to use a drill. The drill bit you use will depend on the task at hand and should be kept in your toolbox for various projects. A twist drill bit is needed for drilling holes, while screwdriver bits are for driving screws in with a drill.
Choose a bit that matches your project and drill a slightly smaller hole than the screw to ensure a firm bite into the material. Phillips and flathead options are available for drill bits, and it doesn’t have to be an exact match to the screw. As long as the bit fits into the slots on the screw, it works.
Drill Bit Maintenance
Drill bit maintenance is crucial for extending the life of your drill bits and ensuring safety. They are cutting tools, and dull or damaged drill bits can lead to increased work time, effort, and damage to materials. A sharpening tool can be a good investment to keep your drill bits in top shape.
Most drill bit sets come in a case with space to hold each bit in place, providing organization and easy access to the right bit for your project. If your set doesn’t come with a case or you’ve been buying individual drill bits, add a storage box with dividers to your toolset.
Tips for proper drill and drill bit maintenance include letting the drill bit cool off after finishing your project, wiping the drill and bit with a clean, dry cloth, brushing off any debris with a clean, dry toothbrush, applying machine oil lightly with a paper towel or microfiber cloth, letting it sit for a few minutes, and wiping up any excess oil with a new paper towel.
Inspect drill bits for any extensive damage and remove damaged ones from the set to be replaced. Place drill bits back into their case and store in a cool, dry place.
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How to Change a Drill Bit?
To change a drill bit, follow these steps:
1. Disconnect the drill from the power source, either by removing the battery or unplugging it.
2. Open the chuck, which will be a circular piece with the bit in the middle. Rotate it until you see the chuck open. If you need a key, use the chuck key that came with the drill to open it.
3. Pull out the bit if it’s stuck. Put the old bit in a case or off to the side.
4. Insert the new bit into the chuck as far as it can go, ensuring it’s centered and not angled. Twist the chuck tightly around the drill bit.
5. Ensure your drill bit is snugly held.
How to Use a Drill?
To use a drill, figure out where you need screws, finish all measurements, and ensure any straight lines are level. Mark each hole with a pencil using a tiny X or make a dot. Always wear protective glasses or goggles when using power tools and secure loose clothing and hair before working.
To drill a hole, power up the drill, adjust the torque to suit the material you’re drilling, find the Xs or dots to mark where to drill, get at the correct level to drill the hole, stabilize the drill vertically, and gently pull the trigger.
For inserting a screw into a pilot hole, power up the drill, adjust the torque, fit the screw into the slot on the drill bit, line up the screw with the hole, ensure the drill is vertical, and press gently into the screw to keep it in place.
If you’re concerned about over-screwing, stop before the screw is completely inserted and finish with a screwdriver.
Drilling is a cutting process that uses a drill bit to cut a hole of circular cross-section in solid materials. There are 20 types of drill bits, and choosing the right one depends on your specific needs and requirements.
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Conclusion
Drill bits are the cutting tools used in drilling machines to create round holes in various materials. Available in a wide range of types and sizes—such as twist bits, spade bits, masonry bits, step bits, and countersink bits—each is designed for specific applications and materials.
Selecting the right drill bit type and material (like high-speed steel, carbide, or cobalt) is essential for efficiency, accuracy, and tool life. Proper usage and maintenance ensure consistent performance and reduce wear or breakage.
FAQs on Drill Bits
What is a drill bit?
A drill bit is a rotating cutting tool used to make cylindrical holes in materials like wood, metal, plastic, or masonry.
What are the most common types of drill bits?
Common types include twist bits, spade bits, masonry bits, brad-point bits, Forstner bits, and step bits.
Which drill bit should I use for metal?
High-speed steel (HSS), cobalt, or carbide-tipped drill bits are suitable for drilling into metal.
What type of drill bit is used for concrete or masonry?
Masonry bits with carbide tips are designed for use on brick, stone, and concrete.
How do I keep my drill bits sharp?
Use them at the correct speed, apply steady pressure, and sharpen them with a bench grinder or a drill bit sharpener when needed.
Why does my drill bit overheat or dull quickly?
Overheating is often caused by using the wrong speed, excessive pressure, or not using cutting fluid for metal drilling.
How can I tell if a drill bit is worn out?
Signs include burn marks, slower cutting performance, squealing sounds, and dull or chipped edges.