21 tipos de brocas utilizadas no fabrico de peças

Drilling is one of the most common processes in manufacturing. With so many types available, it’s important to choose the right one for the job. This guide will walk you through the 21 types of drill bits used in part manufacturing.

What are Drill Bits?

A drill bit is a tool that you attach to a drill to make holes in different materials. Most drill bits are round and have sharp tips to cut through surfaces. They come in different sizes and shapes to create various types of holes.

Components of A Drill Bit

Even though drill bits come in different types, they all have similar parts. Here are the main parts of a drill bit.

Corpo: The main section between the shank and the tip.

Point: The sharp, cone-shaped tip that does the cutting.

Haste: The end that fits into the drill.

Tang: The outermost part of the shank that connects to the drill’s spindle.

Flautas: Spiral or straight grooves along the body that help with cutting, remove debris, and allow coolant to flow.

Land (or Margin): The raised edges next to the flutes.

Body Clearance: A slightly thinner part of the body that reduces friction when drilling.

Web: The section between the flutes.

Neck: The small part that connects the shank to the body.

21 Types of Drill Bits Used in Part Manufacturing

In this section, we discuss the different types of drill bits and uses.

Brad-Point Drill Bit

Best for: Drilling precise holes in wood

This drill bit has a sharp point in the center to keep it steady while you drill. It also has wide grooves to remove dust and chips, keeping the hole clean. It’s great for making neat holes in wood, like when installing cabinet handles.

Twist Drill Bit

Best for: General-purpose drilling in wood, plastic, and light metal

This is the most common drill bit. It has a spiral design that removes dust while drilling, which is why it is easy to create an accurate hole quickly.

Pocket Hole Drill Bit

Best for: Drilling angled holes for screws

This bit is made for drilling slanted holes, also called pocket holes, to join pieces of wood together. It helps secure screws at an angle, similar to nailing wood at a 45-degree angle.

Screwdriver Drill Bit

Best for: Driving and loosening screws

These bits turn your drill into a screwdriver. They come in different shapes to fit various screw types. They are useful for building, repairs, and furniture assembly.

Masonry Drill Bit

Best for: Drilling into brick, concrete, and mortar

These bits are used with hammer drills to break through tough materials. They are commonly used by plumbers and electricians when working on walls.

Rivet Drill Bit

Best for: Drilling rivet holes in thin metal sheets

These bits make holes for rivets, which are fasteners used to hold metal pieces together permanently.

Glass Drill Bit

Best for: Drilling through non-tempered and ceramic glass

These bits have a special tip that drills into glass without cracking it. You need to drill slowly and apply light pressure to avoid breaking the glass.

Drill Saw Bit

Best for: Cutting irregular holes in wood and metal

This bit can drill down and also cut sideways. This is useful for widening holes or creating unusual shapes.

Annular Cutter Drill Bit

Best for: Cutting circular holes in metal while keeping the core intact

Similar to a hole saw, this bit cuts clean holes in metal and leaves a neat core.

Spade Drill Bit

Best for: Drilling large holes in wood

These flat bits have a sharp center point and are often used by electricians to make holes for running cables.

Installer Drill Bit

Best for: Drilling through walls and installing wiring

These long bits (up to 18 inches) can drill through walls, and they have a hole at the tip to help pull wires through.

Step Drill Bit

Best for: Drilling holes of different sizes in sheet metal

These bits have a stepped design that lets you drill various hole sizes without changing bits.

Adjustable Wood Drill Bit

Best for: Drilling different hole sizes in wood

You can change the size of the hole without switching bits. But these wear out faster than regular drill bits.

Auger Drill Bit

Best for: Drilling deep holes in wood

These long bits have a screw tip to help pull them through wood, making deep drilling easier.

Tile Drill Bit

Best for: Drilling through tiles

Similar to a glass drill bit, these have carbide tips to cut through tile without cracking it. Check the packaging to make sure the bit works for your tile type.

Plug Cutter Drill Bit

Best for: Cutting wood plugs to hide screws

Used in woodworking, these bits create wooden plugs to cover screws and make projects look neat.

Countersink Drill Bit

Best for: Creating recessed holes for screws

These bits make a small cone-shaped space so screw heads sit flush with the wood surface.

Self-Feed Drill Bit

Best for: Cutting precise circular holes in wood

These bits have a screw tip to pull them through wood, but they don’t remove sawdust, so you’ll need to stop and clean as you drill

Forstner Drill Bit

Best for: Cutting flat-bottomed holes in wood

These bits make smooth, precise holes for dowels and other woodworking projects.

Coring Drill Bit

Best for: Drilling large holes in brick, concrete, and masonry

You use a coring drill bit to cut smooth, clean holes in tough materials like brick, concrete, and tile. It removes a solid core. It makes installation easier for pipes, ducts, and wires. Water can help cool the bit for smoother drilling.

Hole Saw Drill Bit

Best for: Drilling large holes while keeping the core intact

These bits have a round cutting blade and are used for making big holes in wood, metal, tile, and plastic.

Materials Used in Making Drill Bits

Drill bits are made from different materials, which affects how strong, hard, and heat-resistant the drill bit is. Below are the most common materials used to make drill bits and what they are best for.

Aço de alta velocidade (HSS)

These drill bits are made from a mix of tungsten, chromium, carbon, and vanadium. They are strong, durable, and resistant to heat and wear. Since they can drill at high speeds, they are called High-Speed Steel. You can use them to drill metal and hardwood.

Carboneto de tungsténio

Tungsten carbide is extremely hard and durable. Because of its high cost, it is usually only used on the tips of drill bits. These bits can drill almost any material.

Aço carbono

Carbon steel drill bits come in two types:

Low-carbon steel drill bits: Best for soft materials like wood and plastic. They are not very durable and lose their sharpness quickly.

High-carbon steel drill bits: These are stronger because they go through a heat-treatment process. They can drill through hardwood, metals, and plastic, but they can become dull if they overheat.

Polycrystalline Diamond (PCD)

These drill bits are made with diamond particles bonded to tungsten carbide. They are the hardest type of drill bit and can cut through any material. However, they are very expensive, so they are mostly used for industrial purposes.

Cobalt Steel Alloy

These drill bits contain 5-8% cobalt. They are hard, heat-resistant, and a bit brittle. They are great for drilling aço inoxidável and other tough metals.

Coatings Used on Drill Bits

Drill bits often have special coatings to make them stronger, last longer, and work better on different materials. Here are some common coatings and what they do:

Óxido preto

This is the most affordable coating. It helps protect the drill bit from rust, makes it stronger, and reduces friction. It also helps the bit hold onto drilling lubricants better. Óxido preto works well for drilling iron and steel, but you shouldn’t use it for aluminum, magnesium, or similar materials.

Bronze Oxide

This coating helps make the drill bit stronger and more heat-resistant. It is often used to identify cobalt steel drill bits or combined with black oxide for high-quality, high-speed steel bits.

Nitreto de titânio (TiN)

This is a more expensive coating that makes the drill bit harder and more heat-resistant. It helps the bit last longer and drill faster, especially in tough materials. TiN-coated bits work well for iron, steel, aluminum, magnesium, and other metals. They also provide the same benefits as black and bronze oxide coatings.

How to Select the Right Drill Bit?

There are many types of drill bits, and here’s how to make the right choice.

1. Choose the Right Material

Drill bits are made from different materials, and each one is best for certain jobs. High-speed steel (HSS) works well for wood, aluminum, PVC, and fiberglass. Cobalt drill bits are very hard and great for drilling tough metals. They also release heat quickly.

2. Consider the Coating

Coatings improve a drill bit’s performance and durability. Titanium nitride (TiN) coating makes HSS drill bits harder, so they can drill tougher materials. If you’re working with hard materials, look for coated drill bits.

3. Match the Drill Bit to the Material

Different materials need different drill bits. Use twist drill bits, step drill bits, or straight flute drill bits for metals. Then, use auger bits or spade bits for wood. Always check if the drill bit is meant for the material you are working with.

4. Consider the Drill Bit Shape and Size

Some important features to check:

Thickness (Webbing): A thicker drill bit is stronger and less likely to break. Heavy-duty bits are more durable.

Length: Short drill bits are more precise and stable. If you need a long drill bit, choose one with a short flute length (about twice the drill diameter).

Drill Point Angle:

• 118° angle: Best for softer materials like mild steel and aluminum.
• 135° angle: Better for harder materials.

Helix Angle (Spiral Angle):

• 10-29°: Works well for hard materials like aluminum, providing better chip removal.
• 19-49°: General-purpose angle for most drilling applications.
• 27-45°: Best for very hard materials like stainless steel, requiring less force.

5. Pick the Right Size

Use a drill bit size chart to find the exact size you need. Drill bits come in different size systems, such as:

• Fractional Inch
• Wire Gauge and Letter Sizes
• Metric Sizes

Understanding Drill Bit Angles

The angle of a drill bit is the angle between its tip and cutting edge. There are two common drill bit angles: 118° and 135°.

A 118° drill bit is sharper and cuts quickly. As mentioned earlier, it works best for soft materials. A 135° drill bit has a flatter tip, so it is better for drilling into hard materials like masonry.

When drilling metal, you’ll find drill bits with different angles, such as 90°, 120°, 135°, 140°, and 145°. The right angle depends on the type of metal and the drill bit material.

General rule: the harder the metal, the larger the angle (flatter tip) you should use.

Understanding Drill Bit Shanks

The shank is the part of the drill bit that fits into the drill’s chuck. There are different types of shanks, and you need to choose one that matches your drill’s chuck:

Hex Shank: Has six sides and is used in screw guns or electric screwdrivers, especially those with a hammer mode.

SDS Max Shank: Has grooves that lock into the chuck of hammer drills and some regular drills. It’s used for heavy-duty drilling.

SDS Plus Shank: Another grooved type, mainly used for masonry drill bits.

Straight Shank: A smooth, round shank that works with drills that have keyed or keyless chucks, usually holding bits between 10-13 mm.

Threaded Shank: Has a thread that screws into a hand-held drill. Since these drills don’t have a chuck, they are more compact and great for working in tight spaces. Some threaded shank bits are also made for grinders instead of power drills.

You can buy drill bits with these shank types individually or in sets, including mixed sets with different shanks.

Conclusão

Choosing the right drill bit is important for getting the job done right. With so many types available, it helps to know which one works best for your needs.

If you need high-quality drill bits for your manufacturing needs, contact DEK. We have a wide range of durable and precise drill bits for any job. Check out DEK hoje e obter um orçamento gratuito.

FAQs

What drill bit stays sharp the longest?

Titanium drill bits stay sharp longer than most other drill bits. But if you need to sharpen them, you have to recoat them, which can be a big drawback.

Which drill bit is best for metal?

Cobalt drill bits work best for metal, like stainless steel and aluminum. But you should also think about the size and length of the bit before choosing one.

Why do bits overheat in CNC machines?

Drill bits overheat in CNC machines when there is too much friction. This can happen if you run the machine too fast, use the wrong speed, or don’t use enough coolant. Dull bits and too much pressure can also cause overheating. To avoid this, use the right speed, keep the bit sharp, and make sure there is enough cooling.