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Comprehensive Guide on How to Choose the Right Drill Bit for Your Job
A drill bit is an attachment used with a drill that serves to bore holes in various materials, easily creating openings for construction or other applications. Drill bits actually come in various types to allow drilling into materials with different surfaces and textures, as each type of drill bit is designed for different uses, such as drilling concrete, steel, plastic, wood, and more. Today, we will guide you on which type of drill bit is best suited for your work to achieve maximum efficiency. Let's read on to find out.
How many types of drill bits are there?
Drill Bit Divided into 6 types based on different uses and purposes
1. Center drill bit
This type of drill bit is a tool used for drilling small, conical holes to serve as a starter guide for further drilling or thread tapping. It features a sharp cutting tip made of cast iron, copper, aluminum, or steel. The tip has a narrower angle than other bits because it is used only for center-starting. It is divided into 3 types: type A, type B, and type R, each designed to prevent damage caused by deformation that could lead to an inaccurate center.
2. Metal drill bit
This type of drill bit is designed to easily drill into both hard and soft materials. It features a spiral flute design with a sharp tip to prevent wandering during drilling. It can be used to drill wood or steel. For steel drilling, the bit is engineered to withstand heat well while maintaining excellent hole quality. It is widely used in construction and general industrial work, though it may break easily if it encounters extremely tough structural materials.
3. Drill for Concrete / Masonry
This type of drill bit is designed for drilling into materials like masonry, concrete, blocks, and bricks. It features a twist flute, with the tip made of specially hardened steel while the drill body is made of a softer metal than the cutting tip. It is further divided into several styles, such as round shank masonry bits, rotary hammer bits, and concrete hole saws. Ideal for drilling holes for general fastener installation. Some drill bit types can penetrate reinforced concrete, stone, and steel mesh because the tip is made from the highest grade carbide, allowing precise, effortless drilling and clean, perfect holes.
4. Drill for woodworking
This type of drill bit is easily recognized by its pointed tip with a slight downward angle. Available in both pointed and screw-threaded tips, it is popular for drilling holes in furniture, woodwork, and carvings. It features a small shank and easily drills large holes. Lightweight yet durable for long-term use. Some bits are alloyed with cobalt for high heat resistance, efficiently drilling both softwood and hardwood, plywood, and fiberboard, delivering your desired size and shape.
5. Spade bits / Flat bits
Spade bits have a pointed center tip with flat, paddle-like wings flaring out at an obtuse angle. Compared to standard drill bits, the shank size is not too large, allowing smaller drills to chuck this type of bit. Inexpensive, its tip allows highly precise and accurate hole placement. Ideal for drilling wood, furniture, and plastic without trouble, and lighter in weight than other bits of the same size.
6. Step drills
This type of drill bit resembles an inverted tiered pagoda. Hole sizes can be easily identified by the numbers marked on each step along the side of the bit. It can be used on wood, steel, and aluminum, and can drill through thick metal up to the step height of the bit. Ideal for drilling brackets, shelving, plastic, and aluminum; titanium-coated and eliminates the need for pilot drilling. Issues like bit burn, breakage, and wobble are eliminated because the bit's stepped design performs smoothly as it steps down through the cut.
What factors should be considered when choosing drill bits?
Key considerations for choosing and purchasing Drill Bit You should also consider whether the drill bits you purchase will be suitable for the workpieces you need. Here are some essential points to consider before making a purchase.
Check the drill bit length
Drill bits generally come in various lengths for different tasks. You should consider your workpiece requirements regarding how deep or shallow the drilling needs to be. Longer drill bits often have lower rigidity and can easily wobble during drilling. Therefore, shorter drill bits may perform better in certain situations.
Required hole depth in the workpiece
Certain drill bit portions affect the relationship with the drilled hole depth; the primary factor directly impacting this is the flutes, which function to evacuate chips produced during drilling that can sometimes clog these flutes and potentially cause the drill bit to break. When drilling materials, you must allow for chip evacuation clearance during drilling of approximately 2 times the drill bit diameter; for example, when drilling material to a depth of 12 mm, it is recommended that the flute clearance allows for a drill bit diameter of 6 mm.
Type of drill bit
Standard drill bits will continually decrease in performance when working on large quantities of workpieces. For example, doing 10,000 operations per day might require resharpening every 500 times. However, using high-quality drill bits can significantly save sharpening time and tool-change downtime. Choosing the right type of drill bit for your workpiece is essential for improving operational efficiency. Other factors to consider include frequency of use, material type, and drill bit point angle—for instance, a 118-degree drill bit is used for softer materials such as aluminum, while a 135-140-degree drill bit is used for high-hardness materials like hardened steel and alloy steel.
Self-centering feature of the drill bit
Drill bits with point geometries made from high-speed steel with cobalt (HSS-Co) and carbide offer the advantage of drilling easily without requiring a center punch beforehand. On the other hand, non-self-centering drill bits require center-punching first to prevent the drill bit from slipping or wandering off-target during drilling.
Furthermore, drilling workpieces with drill bits also depends on other factors, such as determining which applications require coolant during drilling, whether to use a constant or high drilling speed, and many other considerations. You should consistently keep your drill bits ready for use, such as keeping them properly sharpened at all times. Drill bits should be removed and the chuck readjusted into place after every use. Apply grease to the gears and drill chuck once a month, choose drill bits suitable for the material type and hole size, and ensure the cutting edges start drilling at the correct location.