How to Cut Slate

Co-authored by wikiHow Staff

Last Updated: February 24, 2023 References Approved

If you're working on a project at home and you're using slate, you may need to cut it to fit it into different spaces. To cut slate, you'll need to mark the slate so that you have a line to cut across. Then, you'll need to use a chisel and hammer, handheld slate cutters, or a power saw to cut it. If you use the correct tools and take your time, you can cut straight and precise lines with a little practice.

Method 1

Method 1 of 4:

Marking the Slate and Preparing to Cut

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Flip the slate over when manually cutting the slate. It’s much easier to draw and cut a straight line across the bottom side of the slate. When cutting slate manually with a hammer and chisel or a handheld slate cutter, flip it over and cut along the flat underside of the tiles.^{[1]
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- To minimize the amount of dust produced when you cut your slate, soak the slate in water for a minute or two before you cut it.
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Mark and cut the top of the slate when using power tools. When using power tools, it's more important that the slate lies flat on the surface you're cutting on. In this case, you'll mark the top of the slate.^{[2]
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Use a straightedge and a pencil to mark a line. You can use a ruler or a straight piece of wood as your straightedge. Put the ruler or wood on top of the slate and use a pencil to draw a straight line across the section that you want to cut. This line will guide you as you cut your slate.^{[3]
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- You may find that your pencil line is hard to see or easily washes off when you use your wet cutter. If this happens, you can use a grease pen, white China pen, or masking tape to mark your line.
4
Work in a well-ventilated area. When you cut slate dust and particles will fly into the air. These are harmful to inhale and can also get into your eyes. Open all of the windows or work outside.
- Keep the sawdust away from you by positioning a fan near your workstation. The fan should point in one direction, blowing the sawdust away from you.
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Wear goggles, a facemask, construction gloves, and the proper attire. As you cut slate, dust will fly into the air and could get into your eyes or mouth. In addition to the proper safety gear, you should also wear closed-toe shoes, thick pants, and a work shirt that you don't mind getting dirty.^{[4]
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- Even with your protective gear, you can get injured when cutting slate. Make sure you don't stand in the path of your blade discharge, as flakes of slate may fly out and strike you.

Method 2

Method 2 of 4:

Utilizing a Chisel and Hammer

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Use a chisel and hammer when cutting through thin slate. The chisel and hammer method may not be the most accurate way to cut slate, but it's one of the easiest ways. This method is best used on thin slate, as the chisel may not be able to cut through thicker pieces of slate.
- Your chisel should be sharp and cold.
- Don't try to force your cut. It will likely take several passes for you to cut through the slate in a clean cut.
2
Line a straightedge up with the line that you drew. Get the straightedge that you used to mark your line and place it over the slate. The line and edge of the wood or ruler should line up.^{[5]
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Score the slate along the line with a chisel. Place your chisel along the side of the straight edge and drag the chisel across the slate to score it. Use the straightedge to guide your chisel so that you keep the line straight. Apply enough pressure to get a clear line, but don't push too hard or you could crack the slate. There should now be an indentation in the line that you drew.^{[6]
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- You can also use a carbide-tipped pencil or the sharp edge of a trowel to score the slate.
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Place the chisel on the line and lightly tap on the top of it. Put the flat, straight side of the chisel into the indentation that you created. Lightly tap the top of the chisel with a hammer to break off sheets of slate. Continue to work down the line in the slate until the piece that you want is cut. If you scored the slate well, it should break off in clean, straight pieces.^{[7]
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Method 3

Method 3 of 4:

Cutting the Slate With a Slate Cutter

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Use a slate cutter when cutting through slate that's medium thickness. This tool has special carbide tipped blades that are resistant to wear when cutting slate. They look like shears or large scissors and will cut through slate fairly easily. Use these if you have to cut through slate that's somewhat thick.^{[8]
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- Slate cutters can be found online or at a hardware store.
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Line the straight edge up with the line. Place the straight edge that you used to mark the slate on top of the slate. This will help guide you as you score and cut the slate.^{[9]
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Score the line that you drew with a sharp tool. Use the sharp edge of a trowel, chisel, or carbide tipped pencil and press down and drag down along the line that you drew. This should create a slight indentation in the slate.^{[10]
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4
Line the slate cutters up with the scored line that you made. Place the blades of the cutters on the line. One blade should be on top of the slate and the other blade should be under it. If the piece of slate is big, clamp it down on a workbench so that it stays still while you cut it.
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Squeeze the handles together and cut the slate. Hold the handles with both hands and squeeze to start cutting the slate. You'll have to apply a moderate amount of pressure on both handles, but the blades should be sharp enough to cut all the way through. Continue to cut down the line as straight as you can. Excess slate will fall to the side.^{[11]
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Method 4

Method 4 of 4:

Using Power Tools to Cut Slate

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Buy or rent an angle grinder or circular saw to cut through thick slate. Angle grinders and circular saws are suited to cut slate. Make sure to use a carbide or diamond tipped blade because slate will dull weaker blades. Also, your cutter wheel should be as thin and fine as possible, which will reduce spalling.^{[12]
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- Use an angle grinder to cut through slate that’s more than ¹⁄₂ inch (1.3 cm) thick.^{[13]
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- Renting cutting equipment can cost $15-$50 (USD) per day.
- Circular saws and angle grinders can cost anywhere from $50-$200 (USD).
2
Clamp your slate over the edge of a workbench. It’s important that your slate doesn’t shift around as you cut it or you may make uneven lines. Clamp the slate so that the part you're cutting off hangs over the workbench. If you don’t hang the slate over a flat surface you’ll cut through whatever it’s resting on.^{[14]
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Place the blade along the line and pull the trigger. Plug in the saw and turn it on. Using both hands, carefully place the blade above the line that you drew. Pull the trigger and the blade will start to spin.^{[15]
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Cut down the line that you made. Slowly lower the angle grinder on the line and move it up and down slightly to cut through the slate. Continue holding the trigger down and move the angle grinder down the line that you drew before. Once you’re done, you should have a straight edge.^{[16]
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