How to Drill Granite & Stone Countertops: Best Diamond Drill Bits & Hole Saws

Working with granite or other natural stone isn't as straightforward as drilling into wood or concrete. These materials are extremely dense and brittle, so using a regular drill and bit can quickly lead to broken tools or cracked stone.

This guide will show you how to drill into granite countertops and other stone surfaces the right way. We’ll cover the equipment you need (like the proper power drill and diamond-tipped bits), and walk you through a step-by-step technique for drilling clean holes. By following these tips, you can avoid common mistakes and successfully drill through stone without damage.

What You Need to Drill Into Granite & Stone

Before drilling into natural stone or granite, it’s crucial to have the proper equipment and setup. Not all drills or bits are suited for hard stone. Using the wrong kind of tool can ruin your material or even pose safety hazards. Below is a breakdown of the right tools for drilling granite and stone and how to choose them.

Choosing the Right Drill for Granite & Stone

Different drilling tools have different strengths. Here are some common drill options and how they perform on granite and stone:

• Standard Drill (Not Recommended): Regular household drills simply lack the power to penetrate granite. Designed for softer materials like wood or metal, they will just skid over a granite surface without making a dent. This quickly dulls the bit and may even scratch the stone.

• Hammer Drill (Use with Caution): A hammer drill adds a pounding action to the bit's rotation. That extra impact is useful for concrete but too aggressive for granite – it can easily crack the stone. If you do use a hammer drill on granite, turn off the hammer function and use only the rotary mode to reduce the risk.

• Rotary Drill (Best Choice): A high-torque rotary drill is the best tool for drilling into granite or other hard stone. It provides steady power without the hammering effect, giving you precise control. It's also important to use a drill with variable speed settings so you can drill slowly and keep the bit cool.

• Angle Grinder (With Diamond Disc): An angle grinder with a diamond cutting wheel can be used to cut or widen existing holes in stone, but it's not ideal for starting a new clean hole. It takes a very steady hand to grind a perfect circle without the grinder slipping off mark. Many professionals do use 4.5-inch angle grinders to cut stone, but for drilling accurate holes a dedicated drill with the proper bit is much safer.

Choosing the Best Drill Bits & Hole Saws for Granite & Stone

Using the right bit is just as important as choosing the right drill. Ordinary bits won't cut it for granite – you need abrasive, diamond-coated bits that can grind through hard stone:

• Carbide-Tipped Masonry Bits: These are made for brick and concrete and can handle some softer stones, but they struggle with granite's hardness. They will dull very quickly (or even snap) if used on granite, and could end up damaging the stone. In short, carbide masonry bits are not a good choice for drilling into true granite.

• Diamond-Tipped Drill Bits: For small-diameter holes in granite, you will need bits that have a diamond-coated tip. The industrial diamond grit on these bits allows them to grind through tough stone. They excel at making pilot holes and small anchor holes cleanly. Just remember to keep the bit cool with water as you drill so it doesn't overheat.

• Diamond Core Hole Saws: To cut a large hole (for example, for a faucet or pipe), a diamond core hole saw is the proper tool. This is a hollow, cylindrical bit with a diamond-coated rim that removes a circular plug of stone, leaving a clean opening. Always start with a pilot hole to guide the larger hole saw and keep it from walking. And as with any diamond tool, use plenty of water to lubricate the cut and keep the bit cool.

How to Drill into Granite & Stone (Step-by-Step Guide)

Drilling through granite or any stone surface requires patience and a methodical approach. Rushing the job or using improper technique can lead to cracked stone or ruined tools. Follow these steps to drill a clean hole in granite or stone:

1. Gather Your Tools and Safety Gear: Before you begin, make sure you have all the necessary equipment. This includes a powerful rotary drill, the right diamond drill bits (a small pilot bit and a larger diamond hole saw), a supply of water for cooling, sturdy clamps to hold the stone, and personal protective gear (safety glasses and a dust mask).

2. Mark the Drilling Spot and Secure the Stone: Apply a piece of painter’s tape where you plan to drill (to help prevent chipping), and mark the exact spot on the tape with a pencil. Next, clamp your granite or stone piece firmly to a stable surface so it cannot move or vibrate. Good support is essential for a clean, accurate hole.

3. Start Drilling at a Low Speed: Attach a small diamond bit to your drill and position it at a 90° angle over your mark. Begin drilling slowly with light pressure to create a shallow pilot divot in the stone (this guides the larger bit and prevents wandering). Make sure to keep the drill bit cool by steadily dripping water onto the area as you drill. The water will also carry away stone dust.

4. Use a Diamond Hole Saw for Larger Holes: If you need a bigger hole, switch to the diamond core hole saw after the pilot hole is established. Continue drilling at a moderate speed, keeping the drill straight and perpendicular to the surface. Add water continuously to cool and lubricate the cut. Do not press down too hard; let the diamond abrasives do the work. It's also wise to pause briefly every 20–30 seconds to prevent the bit from overheating.

5. Finish the Hole and Smooth the Edges: As soon as the drill bit (or hole saw) cuts through the opposite side of the stone, ease off the pressure and let it complete the cut. Gently pull the bit out of the hole. The new hole's edges might be a bit rough, so use a diamond polishing pad or fine-grit sandpaper to lightly smooth around the inside of the hole until the edges are clean and not sharp.

Common Problems and How to Avoid Them

Even with the right tools and approach, you might encounter some issues when drilling into granite or stone. Here are a few common problems and how to prevent them:

Why does granite crack while drilling?

Granite can crack during drilling if you apply too much force, if the slab isn’t supported firmly, or if the drill bit overheats. Pushing down too hard or using a hammer action puts excessive stress on the stone, and any vibration can cause splits. To avoid this, use light pressure, clamp the granite securely so it cannot move, and keep the drilling area cool with water to prevent heat build-up.

Why is my drill bit overheating?

A drill bit will overheat when there's too much friction – usually from drilling at high speed or using a dull bit. An overheated bit not only wears out faster, it can also damage the stone. To prevent overheating, slow down your drilling speed and use water to cool the bit as you work. It's also a good idea to pause periodically and let the bit cool for a few seconds. If a bit has been overheated too many times, it may have lost its cutting edge, so consider replacing it.

Why did my drilled hole turn out jagged or uneven?

If your hole isn't clean and smooth, it likely means the drill bit wandered or wobbled while you were cutting. The best way to get a clean hole is to start with a small pilot hole to guide the larger bit or hole saw. The pilot hole keeps the tool centered so it cuts evenly. Also, make sure you applied steady pressure and kept the drill straight. Drilling at a consistent speed and angle will help produce a smoother, rounder hole.

Why isn't my drill bit cutting through the stone?

If your bit isn't making any progress, it’s probably the wrong type of bit or it's worn out. Regular steel or carbide bits simply won't cut into granite – you need a diamond-tipped bit. If you are already using a diamond bit and it still won't cut, it might have lost its diamond grit from heavy use. In that case, no amount of force will help – you should replace it with a new sharp bit. Always use the proper bit for the job (small diamond bits for small holes and diamond core bits for large holes) and remember to keep it cool with water.

Best Drill Bits & Hole Saws for Granite & Stone

For quick reference, here are some of the top-rated tools that professionals use for drilling into granite and stone:

Top-Rated Granite & Stone Drill Bits

• Bosch 3/8" Diamond Drill Bit: A dependable small-diameter diamond bit, perfect for making pilot holes or small anchor holes in granite with precision.

• SHDIATOOL Diamond Hole Saw: A high-quality diamond hole saw ideal for cutting medium-sized holes (e.g. for faucets or pipes) in granite countertops. It cuts quickly while minimizing chipping.

• Hilti 4" Diamond Core Bit (DD-BI series): A heavy-duty core drilling bit designed for large holes in very hard stone or concrete. Excellent for professional applications where durability and performance are a must.

Top-Rated Power Drills for Stone Work

• DeWalt DWE1622K Rotary Drill: A powerful rotary drill known for its consistent torque and precision. It’s an excellent choice for core drilling into granite and other hard materials (especially when mounted on a stable stand).

• Makita 4.5-Inch Angle Grinder: A versatile handheld grinder that, when paired with diamond cutting discs, is commonly used to cut or enlarge openings in granite and other stone. While not a traditional drill, it's useful for specialized cutting tasks or trimming countertop holes.

• Hilti DD 150-U Core Drill: A professional-grade core drilling rig capable of chewing through granite, concrete, and other tough materials with large-diameter bits. It’s a go-to tool for contractors when standard drills aren’t sufficient for big jobs.

Conclusion

Drilling into granite and stone is completely doable when you use the proper tools and techniques. Always remember to use a suitable drill (ideally a rotary drill) with diamond-tipped bits or diamond hole saws for the best results. Take it slow, keep the drill bit cool with water, and don't apply excessive force. By following the guidance in this article, you’ll be able to create clean, accurate holes in granite or stone without damaging the material or your equipment.

If you have any questions or need advice on the right tools for your project, we’re here to help. Feel free to contact us for expert guidance. You can also visit the Johnson Tools homepage to explore our full selection of diamond drilling bits, hole saws, and other stone-working tools to make your job a success.