How to Cut Granite 3 Ways
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Knowing how to cut granite is a skill that can help you install floor or wall tile, as well as fabricate granite countertops and related accessories like backsplashes. Cutting granite can be done safely and with precision by wet-cutting and by using the correct tools.
Before You Begin
Depending on the type of granite cut that you need to make—short tile cuts, long countertop cuts, or inside sink cutouts—you may need to use one or a combination of three tools: wet tile saw, wet circular saw, or angle grinder.
Cool, nearly dust-free granite cutting is achieved by applying water to the cutting area and to the blade. While dry-cutting is sometimes necessary, wet-cutting is preferable whenever possible.
Use a continuous-rim diamond blade for wet-cutting. Never use a blade with teeth for cutting granite and other stone. Some diamond blades that appear to have teeth are actually called segmented blades. These blades should be used for dry-cutting. The segments keep the blade cooler and help move waste material away from the cutting area.
Tools for Cutting Granite
Wet Tile Saw
A wet tile saw is usually best for making short, straight granite cuts of up to 24 inches and 2-1/4 inches deep or thinner. Granite tile for flooring or walls usually falls within these dimensions.
Mounted on a table or a stand, a wet tile saw provides a stable surface for making straight cuts with no dust. A wet tile saw continually sprays water on the cutting area to control dust and cool the material.
Wet Circular Saw
A handheld wet circular saw is the best tool to use for granite cuts of up to 10 feet long. Granite countertops, backsplashes, and front edges or aprons typically are 5 to 10 feet long.
A handheld wet circular saw feeds water onto the cutting surface from a bottle mounted on the tool.
Angle Grinder and Drum Wheel
An angle grinder fitted with a diamond blade can be used to dry-cut sink cutouts or to make other short cuts in granite.
An angle grinder with a 4-1/2-inch blade can comfortably cut 1-3/4-inch-thick granite. Use a drum wheel sanding attachment on the grinder to smooth the inside sink radiuses.
Safety Considerations
Double-insulated electric power tools intended for wet/dry use come with an extensive safety section in the instructions. Read this carefully. Among other instructions, a drip loop must be created with the electrical cord to prevent water from running into the electrical outlet.
Wet-cutting granite does not suppress all dust. Always wear breathing, hearing, and eye protection when cutting granite.
If using a conventional table saw, circular saw, or angle grinder, do not apply water to the saw, saw blade, work material, or anywhere else in the vicinity.
What You'll Need
Equipment / Tools
- 1 wet tile saw
- 1 wet circular saw
- 1 angle grinder
- 1 diamond polishing drum wheel
- 1 diamond blade (for wet-cutting)
- 1 segmented blade (for dry-cutting)
- 8 C-clamps
- 1 china marker
- 1 tape measure
Materials
- 1 granite material
- 1 fresh water supply
- 1 painter's tape
Instructions
How to Cut Granite With a Wet Tile Saw
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Prepare Area
Work outside, if possible. If working indoors, lay down plastic sheeting to protect the floor from water. Situate the cutting area near a hose spigot and a GFCI outlet.
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Prepare Wet Tile Saw
With the wet tile saw unplugged, set the guide fence. Test the smoothness of the saw table's lateral movement. With most wet tile saws, a sliding table holds the work material. The table slides toward the cutting blade. Make sure that the cut depth is correct.
If using the recirculating pump, fill the tile saw's lower tray with water to the tray's height marker. If using a freshwater feed, set a 5-gallon bucket below the saw and run the wastewater hose into it.
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Mark Cut Area
Mark the cut line on the granite material with painter's tape or a china marker. Place the granite on the saw's sliding table and make sure that it's firmly pressed against the fence (guide).
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Cut the Granite
After plugging in the tile saw, turn on the water pump. Make sure that the pump is operating correctly and that the water nozzle is spraying continuously in the direction of the cut area.
Turn on the saw. Move the table toward the cutting wheel. Slowly move the granite into the wheel. Let the wheel do the cutting rather than forcing the granite into the wheel.
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Finish Cutting the Granite
Toward the end of the cut, slow down your feed to avoid snapping the end of the granite. Turn off the power. Let the blade fully stop before removing the granite.
How to Cut Granite With a Wet Circular Saw
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Support Granite Material
Lay the granite on a well-supported base. The waste end and the usable side should both be supported. Secure the granite to the base with clamps. Use wood on both sides of the clamp to distribute the pressure and avoid cracking the granite.
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Protect Granite Surface
Because the saw plate can scratch the granite, lay down strips of painter's tape on the surface of the granite where the saw plate will run.
If the waste end will be discarded, eliminate the painter's tape. Instead, cut with the saw plate on the waste side.
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Mark Granite
Mark the cut line with a china marker. For long cuts, you can get clean cuts by using a saw guide. A saw guide can be made with straight lumber or it can be purchased for around $60 to $150.
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Prepare Saw
With the saw unplugged, adjust the depth and angle of the saw. Fill the water bottle with clean water and attach the bottle to the saw.
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Back-Cut the Granite (Optional)
At the end of a long cut, the saw's vibration can sometimes break or chip the granite. First make a 2-inch cut at the end of the intended cut line. This process is called back-cutting. After making the back cut, make the intended cut from the opposite direction.
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Cut the Granite
Plug in the saw. Bring the saw up to speed, then adjust the water supply lever so that a slow, gradual trickle of water is fed to the cutting area. Slowly move the saw forward. Keep the saw plate flat on the granite. Let the blade do the cutting and avoid forcing the saw into the granite.
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Finish the Cut
Toward the end of the cut, continue the saw all the way to the end. Do not force off the waste end. Let the saw remove all material for the waste end to separate.
How to Cut Granite With an Angle Grinder
Since most inside granite cuts around the home are for sink cutouts, these instructions refer to making a cutout in granite for a top-mount or undermount sink.
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Prepare Work Area
Because dry-cutting is involved, cut outdoors and be sure to wear all personal breathing, eye, and hearing protection. Raise and support the granite on all sides.
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Mark the Granite
Use the china marker to mark the intended sink cutout.
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Score a Line
Turn on the angle grinder and score a line about 1/4-inch on the inside of the marked line.
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Cut the Long Lines
Cut the long lines preferably with a wet circular saw, if available. Otherwise, use the angle grinder fitted with a diamond blade. Cut on the scored line. Stop short of each curved 90-degree radius—right before the radius begins to turn.
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Cut the 45-Degree Angles
With the angle grinder, cut a straight line from one side of the radius to the other side. Be careful not to extend beyond the scored line. Let the sink cutout waste fall down on its own. Do not break it out.
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Nibble Out the Corners
With the granite still supported on all four sides, stand on the inside of the sink cutout. Nibble out a radius by pushing the angle grinder from the inside-out, stopping just short of the scored line. Make multiple small cuts, each cut about 1/2-inch apart. Then, move the grinder's blade sideways to knock off the remaining narrow pieces of granite.
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Shape and Polish the Radiuses
With the drum sanding attachment on the angle grinder, continue to shape the radiuses into smooth curves.
When to Call a Professional
Short granite cuts on a wet tile saw are relatively simple. But long granite cuts on countertops can be intimidating since there is no margin for error. Creating sink cutouts in granite countertops requires experience, especially when the intended sink will be an undermount sink. The top rim of drop-mounted sinks will cover up minor granite-cutting errors. But with undermount sinks, the edge of the sink cutout is exposed. So, it's often best to have a stone fabricator make long cuts in granite and sink cutouts.