What kind of drill bits do hammer drills use?

Hammer drills can use a variety of drill bits depending on the material being drilled and the size of the hole needed. The most common drill bits used in hammer drills are:

Masonry Drill Bits

Masonry drill bits, also known as masonry bits or SDS bits, are designed specifically for use in hammer drills for drilling into concrete, brick, mortar, and stone. They are made of tungsten carbide and come in a variety of sizes and tip styles. The most common types are:

• SDS-Plus Drill Bits – Have a splined shank that fits into SDS-Plus chucks found on most rotary and hammer drills. They come in diameters from 3-16mm.
• SDS-Max Drill Bits – Larger version for heavier duty drilling. Diameters range from 5-22mm. Fit SDS-Max chucks.
• Flat Chisel Bits – Used to chip away concrete or make depressions. Come in various widths.
• Pointed Chisel Bits – For chipping into hard materials. Narrow tip makes precise holes.
• Scaling Chisel Bits – Removes chunks of material. Wider tip than pointed chisel.

Steel Drill Bits

Standard steel twist drill bits can also be used with hammer drills when drilling into wood, metal, or plastic. These include:

• High-Speed Steel (HSS) – General purpose steel bits for wood and light metal drilling.
• Cobalt Steel – More heat resistant for drilling stainless steel and other hard metals.
• Black Oxide-Coated – Helps reduce friction and heat. Good for metalwork.
• Titanium-Coated – Very durable, lasts longer than standard HSS bits.
• Carbide-Tipped – Carbide tip adds hardness for cement boards, tile, and masonry.

Specialty Bits

In addition to standard masonry and steel bits, hammer drills can also use special drill bits for specific materials or applications:

• Glass/Tile Bits – Have a tungsten carbide tip to drill into glass and ceramic tile without cracking.
• Auger Bits – Designed for drilling large diameter holes into thick wood.
• Forstner Bits – Cut flat bottom holes for woodworking applications like mortises.
• Hole Saws – For drilling circular holes for electrical boxes, plumbing, etc.
• Diamond Grit Bits – Contain tiny diamonds for drilling into porcelain or ceramic tile.

Bit Shank Types

The shank is the non-cutting end of the drill bit that fits into the chuck of the hammer drill. There are a few common shank types:

• Round Shank – Most common type. Fits into 3-jaw chucks on standard rotary drills and hammer drills.
• SDS-Plus – Has splines that fit SDS-Plus chucks on hammer drills.
• SDS-Max – Larger SDS shank for heavy-duty hammer drilling.
• Hex Shank – Hexagonal shape. Used on driver bits for impact drivers.

Drill Bit Materials

The toughness and hardness of the drill bit material impacts its drilling performance. Common materials include:

• High Speed Steel (HSS) – Good hardness and resistance to heat. Used for general purpose bits.
• Cobalt Steel – Excellent heat and wear resistance. Used for high performance bits.
• Carbide Tips – Very hard carbide inserts on tips/edges provides extreme durability.
• Tungsten Carbide – Entire bit made from tungsten carbide. Most masonry bits are tungsten carbide.
• Titanium Coatings – Added to HSS bits for increased hardness and lubricity.
• Diamond Grit – Tiny industrial diamonds on tip. Used for very hard materials like tile.

Drill Bit Coatings

Special coatings can be applied to drill bits to enhance their performance. Some common coatings include:

• Black Oxide – Provides lubricity and corrosion resistance.
• Titanium Nitride (TiN) – Added hardness and heat resistance. Gold color.
• Titanium Aluminum Nitride (TiAlN) – Similar to TiN but more durable. Gray color.
• Diamond-Like Carbon (DLC) – Slick coating reduces friction and heat. Black color.

Drill Bit Sizes

Drill bits are available in a wide range of imperial and metric sizes. Common size standards include:

• Imperial – Sizes from 1/16″ to 1/2″ by 64ths. Larger bits use decimals.
• Metric – Sizes from 1mm to 13mm in 0.5mm increments. Larger in 1mm.
• Wire Gauges – Numbered sizes based on wire diameter. Common for small bits.
• Fractional – Bits with 1/4″, 1/2″ sizes rather than decimals. Used for wood bits.

Masonry bit sizes are less standardized but the common range is 3mm to 22mm.

Key Considerations When Selecting Drill Bits

• Material Being Drilled – Match drill bit to material. Masonry bits for concrete, tile bits for ceramic, etc.
• Hole Diameter Needed – Choose bit that matches the desired hole size.
• Drilling Depth – Longer bits can drill deeper holes.
• Chuck Type – Select bit shank (SDS, round) to match drill chuck.
• Coatings – Coatings like TiN or oxide help extend bit life.
• Quality – Generally, spend more on bits for frequent use or hard materials.

Conclusion

In summary, hammer drills are highly versatile and can utilize a wide variety of drill bit types and materials depending on the application. The key factors are choosing a drill bit engineered for the material being drilled and matching the shank type to the chuck on your hammer drill. Using quality bits designed for hammer drilling and replacing them as needed will ensure you get the best performance from your hammer drill.