Choosing the right drill bit for your project can seem overwhelming with so many types available. However, knowing the most common drill bit types and their uses will help you select the best option. We cover 20 of the most popular drill bits and tips for choosing the right one for your needs.
Twist Drill Bits
Twist drill bits are versatile for drilling through a variety of materials like wood, plastic, and light metals. They have two spiral grooves running up the body which convey material chips up and out as you drill.
Best Uses: General purpose drilling in softer materials like wood and plastic. Can also drill through thin sheet metal.
Tips for Choosing: Select based on the diameter of the hole needed. Using the proper bit size for the hole prevents damage.
Brad Point Bits
Brad point bits combine a center point with cutting edges on the perimeter. The spur in the center prevents the bit from wandering off center as you start the hole. The sharp cutting edges shear through material cleanly.
Best Uses: Producing clean holes in wood. The spur center creates a guide hole to prevent tearing the wood grain.
Tips for Choosing: Match the bit diameter to the required hole size. Look for sharp, undamaged cutting edges.
Forstner Bits
Forstner bits drill flat-bottomed holes with clean, precise edges. The rim cutters shear materials while the inner drill point clears out the center.
Best Uses: Drilling clean, precise holes for joinery and inlays in woodworking. Produces flat-bottomed holes.
Tips for Choosing: Select the exact diameter needed for your project. Check that cutters are sharp and undamaged.
Auger Bits
Auger bits feature a long, threaded tip to start holes and pull the bit into the material. The threads carry away waste chips as you drill deeper into wood.
Best Uses: Boring deep holes in wood, like those needed for dowels or screws. Useful when you need controlled depth.
Tips for Choosing: Choose length based on desired hole depth. Longer auger bits are better for deep holes.
Spade Bits
Spade bits have a sharp point and flat cutting edges ideal for boring large diameter holes in wood. They remove material quickly with their wide cutting blades.
Best Uses: Rough boring holes from 3/8” to 1-1/2” or larger in wood. Good for quickly boring holes for electrical boxes.
Tips for Choosing: Pick diameter needed. Ensure cutting edges are sharp and free of chips and burrs.
Hole Saw Bits
Hole saws use removable cutter bits that attach to a circular saw arbor. As the hole saw spins, the teeth cut through material to create a large, clean hole.
Best Uses: Cutting neat, circular holes in wood and drywall. Available in diameters from 1/4″ to 6”.
Tips for Choosing: Buy kits that include saw mandrels and pilot bits. Select diameter based on requirements.
Masonry Bits
Masonry drill bits have a carbide tip designed to hammer away and drill holes in brick, concrete, and stone. Special flutes evacuate debris as you drill.
Best Uses: Drilling precise holes in concrete, brick, and other masonry. Useful for installing anchors and fasteners.
Tips for Choosing: Pick diameter matching your needs. Check for wear on carbide tip. Apply oil while drilling masonry.
Glass and Tile Bits
Glass and tile bits have diamond-grit surfaces to grind through tough materials like glass and ceramic tile. Abrasion from the diamonds bores clean holes.
Best Uses: Drilling smooth holes in tile, glass, and porcelain. Used for installing fixtures or shelving in bathrooms and kitchens.
Tips for Choosing: Match bit diameter to hole size. Lubricate with water to keep diamond grit cool. Take it slow.
Countersink Bits
A countersink uses a pilot drill surrounded by angled cutters. As the bit spins, the pilot hole is bored while the cutters create a conical recess around it.
Best Uses: Drilling clearance and seating holes for screw heads in wood and other materials. Creates neatly finished holes.
Tips for Choosing: Buy graduated sets to match different screw head sizes. Use proper diameter for hole and screw size.
Step Drill Bits
Step drill bits incrementally increase in diameter from tip to shank. Each step bores progressively larger holes in the material as you drill deeper.
Best Uses: Boring holes in metal from small starting diameters up to larger sizes. Good for electrical boxes or conduit holes.
Tips for Choosing: Choose length to match material thickness. Longer bits work for thicker metals. Use cutting fluid.
Bullet Pilot Point Bits
These have a sharp point flanked by a seamless bullet-shaped cutting zone. The narrow point starts the hole accurately while the bullet zone speeds drilling.
Best Uses: Fast, precise holes in metal and wood. Point ensures accuracy while bullet tip rapidly drills the hole. Great for computer numerical control (CNC) machines.
Tips for Choosing: Pick bits in exact sizes needed for your holes. Check points are centered and sharp.
Unibit Step Bits
Unibits have tapered steps of increasing diameter. As you drill deeper, each step bores a larger hole size. Stops prevent overdrilling.
Best Uses: Adjustable holes in metal or plastic. Each step drills a specific hole diameter from small to large as needed.
Tips for Choosing: Choose length to match material thickness. Long unibits allow bigger holes in thicker stock. Use cutting oil.
Cobalt Jobber Bits
These extremely durable twist bits are made from high-speed steel melted with cobalt. They stay sharper much longer than standard bits.
Best Uses: Heavy duty drilling in hard metals and stainless steel. Use when you expect high wear on less durable bits. Hold sharpness for 20X longer.
Tips for Choosing: Buy based on how much wear resistance you need. More cobalt gives longer life but costs more.
Left-Handed Drill Bits
These specialty bits turn counterclockwise instead of standard right-handed clockwise direction. They bite in and unscrew stuck fasteners or hardware as you drill.
Best Uses: Removing damaged or stuck screws and bolts. Reverse direction backs stuck fasteners out as you drill into them.
Tips for Choosing: Match size to hardware you need to remove. Keep heavy pressure and slow speed.
Aircraft Extension Bits
Extremely long aircraft extension bits provide extended reach from the drill for boring deep holes. Sections connect via couplings.
Best Uses: Drilling extra deep holes with standard power drills. Extension design reaches depths not typically possible with normal bits.
Tips for Choosing: Select length based on depth of hole needed. Use cutting oil for metal drilling. Take it slow.
Installer Bits
Installer bits feature a hex-shaped shaft that fits into the quick release chucks of power drills. The hex shank provides increased grip and torque.
Best Uses: Heavy-duty drilling with premium power drills. Gives added torque transfer for tough materials like stainless steel.
Tips for Choosing: Ensure the hex shank properly fits your drill’s chuck. Pick length to suit the application.
Reduced Shank Bits
These have a thinner shank than the cutting diameter. The reduced shank concentrates force on the hole for faster drilling with less binding.
Best Uses: Drilling in wood and metal where standard bits may clog or bind. Reduced shank clears chips faster for cleaner holes.
Tips for Choosing: Use for faster drilling in materials where standard bits may bind up. Don’t force them or they may snap.
Titex Multimaster Bits
Multimaster drill bits work in oscillating power tools to cut openings and patterns in wood or drywall. Special geometry cuts on all sides.
Best Uses: Cutting intricate holes and designs into wood or drywall with an oscillating multitool. Unique cutting action drills very clean holes and shapes
Tips for Choosing: Pick size based on the hole dimensions and radii needed. Don’t force them sideways or they may snap.
Core Drill Bits
These hollow cylindrical bits work with special drills to extract solid cylinders or cores of material. Water cools the diamond cutting edge.
Best Uses: Taking core samples from concrete, asphalt, and stone materials. Extracts a neat plug of the base material for analysis.
Tips for Choosing: Match diameter to the core size desired. Larger diameters need rigid setups to prevent core jams.
Spotting Drill Bits
Extremely rigid spotting bits produce very accurate guide holes for starting larger bit diameters on center. They prevent walking.
Best Uses: Drilling pilot and guide holes that must be centered precisely. Essential first step for critical holes before using larger bits.
Tips for Choosing: Buy high-quality spots made with durable carbide tips. Pick small diameter matched to larger bit.
Indexable Insert Bits
These industrial bits have removable and replaceable carbide inserts that do the actual cutting. It allows changing just the insert instead of the whole bit.
Best Uses: Heavy duty drilling in metal where replaceable cutters are needed. Quickly change dull inserts without replacing entire bit.
Tips for Choosing: Select insert geometry to match your metal type and hole specs. Carbide inserts last the longest.
Rotabroach Annular Cutter
Rotabroaches have a unique annular cutter design with razor inserts. As they drill, the cutters slice out the hole edge, leaving perfectly smooth sides.
Best Uses: High precision holes in sheet metals and composites. Cutters shear an ultrasmooth hole edge. No burrs or rough edges.
Tips for Choosing: Buy kits with multiple cutters and hole size bushings. Match bushing to hole size needed.
Fly Cutter Bits
These specialty bits consist of a rotating cylindrical body that holds interchangeable carbide inserts. The inserts shape material as the body spins.
Best Uses: High-precision hole boring, facing, and material removal applications. Carbide inserts create accurate shapes with precision.
Tips for Choosing: Purchase kits with multiple carbide insert geometries for versatility. Ensure rigidity in set up.
How to Choose the Correct Drill Bit for Your Project
With so many drill bit types available, choosing the right one for the job is essential for success. Follow these tips when selecting drill bits:
- Match the bit material to the material you are drilling. Harder materials require more durable drill bits. For example, use cobalt bits for hardened steel.
- Consider the diameter or size of hole needed. Pick bits that closely match the required hole size.
- Factor in the thickness or depth of the material. Longer bits are necessary for deeper holes.
- For metal drilling, use a cutting fluid or oil to keep bits cool and prevent wear.
- For wood drilling, choose bits designed to cleanly cut wood fibers like brad point or Forstner bits.
- Check that the drill bit properly fits your drill chuck. Ensure a solid grip for best results.
- Inspect bits for any damage like chipped edges or worn flutes. Replace worn bits for best performance.
- For repetitive holes, invest in durable bits like those tipped with cobalt or carbide. The extra cost pays off from longer life.
Taking a few moments to consider these factors will ensure you have the optimal drill bit for the material and type of hole you need to make. Using the proper bit goes a long way towards making any drilling project quicker and easier with professional results. With the wide range of drill bits available today, you are sure to find the perfect fit for your next drilling application.
Frequently Asked Questions About Drill Bits
What are the most common types of drill bits?
Some of the most common and versatile drill bits include twist bits, spade bits, brad point bits, masonry bits, Forstner bits, countersink bits, and hole saw bits. Most kits contain these standard bits.
What drill bit is best for wood?
For drilling clean holes in wood, choose brad point bits or Forstner bits. The brad point’s spur center keeps the bit stable while the sharp edges shear wood fibers. Forstner bits excels at flat-bottomed holes for joinery.
What drill bit do you use on metal?
High-speed steel twist bits work for thin metal while cobalt bits are best for thick or hardened steel. Keep metal bits lubricated with oil or cutting fluid. Carbide-tipped bits are also very durable for metal drilling.
What drill bit to use on concrete?
Specialized masonry bits with carbide tips are required for concrete drilling. Apply steady pressure and run the drill at slower RPMs. Lubricate the bit with oil or water to keep it cool.
How do I know what size drill bit to use?
Select drill bits that closely match the required hole diameter. For example, a 5/16” bit is best for a hole measuring 5/16” across. Consult manufacturers’ sizing charts to match numbered bits with hole sizes.
What is the best drill bit brand?
Top drill bit brands known for quality include Dewalt, Bosch, Milwaukee, Makita, Irwin, and Craftsman. Look for bits made with durable high-speed steel or those tipped with cobalt or carbide. Buy bits that match your most common drilling needs.
How can you tell when a drill bit is dull?
Signs of a dull bit include increased effort to drill, smoking, slipping, poor cutting, or jagged hole edges. Dull bits make uneven holes and can damage materials. Replace worn bits for smooth drilling and clean holes.
How are drill bit sizes measured?
Drill bits are measured according to the diameter of the hole they drill. Sizes are denoted by fractional inches, wire gauge size, or decimal inches. Always match your required hole size with the same diameter drill bit.
Can you sharpen drill bits?
High quality drill bits made from durable materials like carbide and cobalt can be sharpened and reused multiple times. Use a drill bit sharpening jig or take them to a professional sharpener. Don’t attempt to sharpen softer bits.
Conclusion
With such a wide variety of drill bits available, choosing the right one ensures you have the best tool for your particular drilling application. Matching the bit to factors like the base material, hole size, and drilling depth will produce professional results quickly and easily. Investing in quality bits made from durable materials will save headaches down the road. Follow these tips to select the optimal drill bit for your next project.