Which Material is Better for Impact Drill Bit? A Comprehensive Analysis

Introduction to Impact Drill Bits and Their Importance

Impact drills have become one of the most indispensable tools for professionals in construction, woodworking, masonry, and metalworking. Unlike regular drills, impact drills are designed to deliver both rotational torque and concussive blows, which makes them far more effective when working with hard materials like concrete, stone, brick, tile, and metals. The core of their performance, however, lies in the drill bit itself. The drill bit material determines not only how effectively the drill penetrates a surface, but also how long it lasts, how much maintenance it requires, and whether it can withstand the high heat and pressure generated by continuous impact drilling. Therefore, selecting the right material for impact drill bits is a decision that directly affects efficiency, cost, and results. Today’s market offers a wide variety of materials ranging from high-speed steel (HSS) to cobalt steel, tungsten carbide, diamond-coated bits, and advanced composites. Each of these materials has unique strengths and weaknesses that make them suitable for certain applications but less ideal for others.

High-Speed Steel (HSS) Drill Bits for Impact Drilling

High-speed steel drill bits are among the most common and affordable materials available for impact drills. They are made from carbon steel alloyed with elements such as tungsten, chromium, vanadium, and molybdenum to enhance hardness and resistance to wear. HSS bits are capable of handling high temperatures without losing their hardness, which makes them more suitable for high-speed rotation compared to traditional carbon steel bits. However, when it comes to impact drilling, HSS bits are not always the first choice, because they wear faster when used against extremely hard materials like reinforced concrete or hardened steel. Still, they are widely used for general-purpose drilling into softer metals, wood, and plastics. Well-known models include the DeWalt DW1177 20-Piece HSS Drill Bit Set, the Makita D-30036 HSS Bit Pack, and the Bosch HSS-R Drill Bits Series. These are ideal for electricians, carpenters, and homeowners who need reliable but affordable bits for day-to-day projects.

Cobalt Steel Drill Bits for Heavy-Duty Impact Drilling

Cobalt drill bits are essentially an upgraded version of HSS bits, made by alloying high-speed steel with 5–8% cobalt content. The addition of cobalt increases the hardness, heat resistance, and wear resistance of the bits, making them suitable for drilling through tough metals like stainless steel, cast iron, and titanium. For impact drills, cobalt bits are a solid option when working with metal applications that require durability under repeated strikes. Cobalt bits also have self-sharpening properties, meaning that the cutting edges tend to maintain sharpness longer than standard HSS. Popular brands offering cobalt drill bits include the Irwin Tools Cobalt M-35 Metal Index Set, the Milwaukee Red Helix Cobalt Drill Bits (48-89-2330), and the DEWALT DW1263 Pilot Point Cobalt Set. These are often recommended for fabricators, welders, and mechanical engineers who frequently work with alloys that would otherwise dull a standard bit quickly.

Tungsten Carbide-Tipped Drill Bits for Masonry and Concrete

When it comes to drilling into concrete, brick, stone, or tile, carbide-tipped drill bits are considered one of the best materials. Tungsten carbide is significantly harder than steel, with extreme durability and resistance to high-impact stress. In impact drills, carbide tips maintain cutting edges sharp for a long period, even when used against reinforced concrete with embedded rebar. One of the most popular types of carbide bits is the SDS (Slotted Drive System) carbide drill bit, widely used in rotary hammer and impact drills for masonry. Notable examples include the Bosch Bulldog Xtreme SDS-Plus Carbide Bit Series, the Makita SDS-Plus 5-Piece Set, and the Hilti TE-CX Carbide Drill Bits. Tungsten carbide bits are ideal for professional construction workers and masons who constantly need to drill anchor holes, run conduit, or work on reinforced structures. The downside is that carbide bits are relatively brittle, which means they can chip if used incorrectly or at improper angles, but under proper conditions, they offer unmatched longevity and efficiency.

Solid Carbide Drill Bits for Precision and Industrial Applications

Unlike carbide-tipped drill bits, which have a steel body with carbide cutting edges, solid carbide drill bits are made entirely of tungsten carbide. These bits are incredibly hard and can drill with extreme precision in applications involving ceramics, composites, hardened steel, or aerospace alloys. Because they are fully carbide, they are more brittle and prone to breaking under lateral stress, which makes them less forgiving in handheld impact drills. However, when used in controlled environments with impact drills designed for fine tolerances, they deliver exceptional performance. Brands such as Guhring Solid Carbide Drills, Kennametal Carbide Tools, and OSG Carbide Drill Bits are frequently seen in aerospace, automotive, and medical equipment manufacturing. These industries prioritize precision over rugged flexibility, making solid carbide drill bits a highly valued choice despite their cost.

Diamond-Coated and PCD Drill Bits for Extreme Hardness

For drilling into extremely hard or abrasive surfaces like glass, ceramics, porcelain tiles, or stone, diamond-coated or PCD (Polycrystalline Diamond) drill bits are considered the superior option. Diamond is the hardest material known, which gives these bits the ability to grind through materials that no steel or carbide could handle. Diamond-coated bits are not designed for heavy hammering but are often used in impact drills at controlled speeds to avoid overheating. For tile installers and stoneworkers, diamond-coated bits are a necessity, especially when working with fragile but hard surfaces. Examples include the Bosch GT3000 Glass and Tile Bit Set, the DEWALT Diamond Drill Bits DW5572, and QEP Diamond Hole Saws for Tile and Stone. These bits must be cooled with water during drilling to prevent cracking and overheating. Although not the most versatile, they provide solutions for highly specialized drilling tasks where other materials simply fail.

Titanium-Coated Drill Bits as an Economical Upgrade

Titanium-coated drill bits are often marketed as premium alternatives to HSS bits. They are typically HSS bits coated with titanium nitride (TiN), which increases surface hardness, reduces friction, and extends the lifespan compared to uncoated HSS. For impact drills, titanium-coated bits provide good performance on wood, plastic, and light metals. However, the coating wears off over time, especially under heavy impact loads, so they are not as durable as cobalt or carbide options. Still, for general-purpose home use, they are a great cost-effective choice. Well-regarded options include the DEWALT Titanium Pilot Point Set DW1361, the Irwin Titanium Nitride Bit Set, and the Milwaukee Shockwave Titanium Red Helix Drill Bits. They are particularly suitable for DIY enthusiasts, electricians, and plumbers who need a reliable set for mixed materials without investing in more expensive cobalt or carbide bits.