What Type of Drill Bit to Use for Drilling Quartz Countertops

Drilling holes into quartz countertops for sinks, faucets, soap dispensers, and other fixtures can seem daunting. However, with the right drill bit, the process is straightforward. Here’s a detailed guide on choosing the best drill bit for quartz countertops.


Quartz countertops are engineered stone made from crushed quartz blended with resins and pigments. This makes quartz harder than natural stone but softer than ceramic tiles. Quartz is also non-porous, so holes can be drilled without risking cracks spreading.

When drilling into quartz, the goal is to get clean, precise holes without chipping or cracking the material. The type of drill bit you use is crucial for this. Let’s look at the factors to consider when choosing a drill bit for quartz.

Diamond Core Drill Bits

Diamond core drill bits are the best choice for drilling into quartz countertops. They have industrial grade diamonds bonded on the tip which grind smoothly through the quartz. Here are the benefits of using diamond core bits:

  • Produce smooth cut holes with clean edges – the diamonds shave off quartz evenly without cracking or chipping.
  • Cool-cutting – diamonds disperse heat well preventing heat damage as you drill.
  • Durable – diamonds maintain sharpness and run at high speeds without losing grit or binding.
  • Clean holes – diamonds grind a neat circle without requiring additional reaming.

Key Features of Diamond Bits for Quartz

Look for the following when choosing a diamond core bit specifically for quartz:

  • Diamond grit size – 50-100 grit size diamonds work well to grind quartz smoothly. Larger diamonds may be too abrasive.
  • Bond – A strong metal or resin bond prevents diamonds from shedding off. Electroplated bonds last longer.
  • Water holes – Essential for cooling and ejecting dust while drilling quartz.
  • Variable speed – Allows matching the right RPM to material hardness. Keep speed 800-1000 RPM in quartz.
  • Pilot point tip – Reduces skidding or wandering for precise hole placement.

Recommended Size of Diamond Bits

The size of the diamond bit depends on the fixtures you are installing:

  • For faucet holes – Use 1 1/4″ or 1 3/8″ diamond bits. This matches standard faucet hole sizes.
  • For soap dispensers – 1 1/2″ diamond bit creates an ideal size hole.
  • For sink cutouts – Use jigsaw with diamond blade then finish edges with a router.
  • For smaller penetrations – 1/4″ or 1/2″ diamond core bits for pilot holes.

Dry or Wet Drilling?

Diamond drilling generates heat which can damage quartz if it builds up. Here are cooling options:

  • Dry diamond bits – Best for shallow holes under 1/2″ deep. The bit ejects dust to prevent heating.
  • Wet diamond bits – Water cools and lubricates deeper holes. Attach to faucet or use water spritzer.
  • Coolant sprays – Special oil- or wax-based sprays prevent overheating of bit.

Wet drilling is best for most quartz holes over 1/2″ depth. The water wash flushes out debris too.

Drilling Tips for Quartz

Follow these best practices when drilling into quartz:

  • Mark hole locations using a template or tape measure.
  • Drill pilot holes first, then enlarge to final size. Pilots prevent skidding of larger bits.
  • Use painter’s tape over holes to prevent chipping the quartz surface.
  • Drill at 700-1000 RPM speed matching bit size and quartz thickness.
  • Let the drill do the work. Apply light pressure. Pressing hard risks cracking.
  • Frequently back bit out to clear dust and maintain cutting speed.

Alternative Methods for Cutting Holes

While diamond core bits are ideal for drilling round faucet and soap holes, consider these methods for specialty holes:

  • For sink cutouts, use a jigsaw with diamond-grit blade first, then smooth edges with a router.
  • For outlets or switches, use an oscillating tool with carbide blades to neatly cut rectangular openings.
  • For irregular holes, create a template and use a router with diamond flush-trim bit to follow the template profile.


With the right diamond core drill bits and proper technique, you can get perfect holes in quartz every time. Select electroplated diamond bits in the appropriate size for smooth cutting action and use water to keep the bit cool. Take it slow and let the diamonds do the hard work. Following these tips will allow you to install fixtures in your quartz countertops without any cracks or chips.

FAQs About Drilling Quartz Countertops

What speed should I run a diamond bit at in quartz?

Between 700-1000 RPM is ideal. Match the speed to the size of the bit – larger bits run at slower speeds. Too fast risks cracking while too slow causes excessive wear.

Can I use regular drill bits for quartz?

No, regular drill bits lack the hardness to cut quartz cleanly. They will likely skid, crack the quartz, and become dull quickly. Always use diamond core bits.

What size pilot hole do I need for a 1 1/4” faucet hole?

Drill a 1/4” or 3/8” pilot hole first. This centers your larger bit and provides entry for the diamonds to start cutting.

Is a hammer drill necessary for drilling quartz?

No, a hammer drill risks cracking the quartz. A regular drill allows better speed control. Use light steady pressure rather than hammering force.

How can I prevent chipping on the underside when the bit breaks through?

Applying painter’s tape around the planned hole location helps support the edges as the bit exits the bottom surface.

Can I drill through thick quartz slabs for a farmhouse sink?

Yes, but work slowly in stages – use a 1/4″ bit for pilot hole, then 1/2″, 3/4″, and finally full sink cutout size. Let the bit cool between passes. Apply water.


The key to clean quartz drilling is using good quality diamond core bits in the proper size along with the right drilling technique. Pilot holes prevent wandering and cooling keeps the diamonds cutting efficiently. With the proper bit choice and methods outlined here, you can add any desired fixtures to your quartz countertops without harming the surface.