A miter saw is the tool for projects that require accurate lumber and moulding cuts — especially angles. But the tool named for cutting miters does so much more.
With a board flat on the base of a miter saw, any angled cut across the wide face counts as a “miter” on any miter saw. Turn the board on its edge, place it against the fence, and you’ll cut a “bevel.” Most saws cut from 90 to 45 degrees in both directions, and some saws can cut up to 55-degree angles.
Saws start to differ when you look at their blade diameter—commonly 10 inches or 12 inches. The bigger the blade, the deeper and wider its maximum cut. Typically, a 10-inch miter saw will cut a 2 x 6 at 90 degrees and a 2 x 4 at 45 degrees; a 12-inch miter saw will cut a 2 x 8 at 90 degrees and a 2 x 6 at 45 degrees.
Saws also differ by whether the blade arm simply rotates (a basic miter saw) or both swings and slides (a sliding miter saw). The sliding action can cut even wider boards. A 12-inch version, for example, will cut a 2 x 16 at 90 degrees and a ���2 x 12 at 45 degrees.
Either can become a compound saw—the blade arm both swings at an angle and tilts at an angle to the bed of the table to cut both a bevel and miter at once. This is primarily used to cut crown moulding.
Always wear eye and ear protection. When working with treated lumber, wear gloves and a dust mask as well. Secure any loose clothing, jewelry and long hair. Keep hands 6 inches from the blade and off the turntable. Do not cross your arms as you cut. Support your work piece with a feed support or stand. Always follow the saw manufacturer's instructions for use, maintenance and safety.
The cut angle and wood thickness determine where the blade will contact the material. When marking a board, extend the line across the stock, drop the blade to the wood to check your alignment, and adjust the board as needed before starting the saw.
When you’re cutting a board, rest more than half its length on the saw. If the board is too long, stack a few scraps next to the saw to support the overhanging board. For a timesaving solution, mount your saw on a saw stand with supports for long stock.
Place the stock against the fence at the back of the saw base, and hold it with your hands (or a clamp) at least 6 inches from the blade. Only then should you start the saw. Always keep your other hand on the saw handle. Both arms should be straight out in front of you, and your feet firmly planted. Never cross your arms when operating the saw.
Start the saw at the top of the operating position, allow the motor to come up to speed, and bring the saw down into the wood. When the board is cut all the way through, release the trigger and allow the blade to completely stop before you raise the blade.
Learn the types of cuts you can make with a miter saw. Watch our DIY Basics video: What's That Cut Called?
If you lift the blade as it’s still spinning, it can toss small pieces into the air and mar the end of the board you’re cutting.
You can speed up repetitive cuts in two ways: Instead of individually measuring parts for identical short cuts, mark the part length on a piece of masking tape attached to the fence. Then remove the tape when you’re done.
For even greater accuracy, attach a stop block. Attach pieces of double-face carpet tape to the back face of a 3/4-inch-thick wood scrap. With the saw unplugged and the blade down, measure from the blade teeth to a point on the fence equal to the part length. There, press the taped block against the fence. With the end of a board pressed lightly against the block, make your cut. Each part you cut after that will be the same length—just blow away any sawdust that can pile up against the stop block.
Expand the chart to the right to get miter and bevel settings for different wall and crown moulding angles.