How to Choose and Use a Circular Saw

By: Julie Day

How To Make A Cut With a Circular Saw

Blue painter's on board.

Painter’s tape can help reduce splintering on fine finish cuts.

Step 1: Measure and Mark Cutting Line

Use a tape measure to mark the location of your cut, then use a square to draw a line the full length of the cut. Circular saws cut in straight lines, but it’s easy to make a crooked cut if you don’t draw a reference line.

If your wood tends to splinter, you can get a cleaner cut by applying painter’s tape or masking tape to the wood along the cutting line, or by making the cut with the back of the board or plywood facing up.

Plywood supported by 2x4s with circular saw and square.

If needed, support the full length of plywood with scrap lumber.

Step 2: Support the Work Properly

Always allow the cut end of the board to fall away freely, and NEVER make a cut in between two sawhorses! As the board is cut, it will begin to sag, which can pinch the blade and result in a dangerous kickback.

If you’re afraid the wood will split as it falls, you can support the entire piece with scrap lumber, making sure that your blade doesn’t cut all the way through the support boards.

I find it easiest to clamp the longer end of the board in place or have a helper hold it, rather than trying to hold the saw with one hand and the board with the other.

Either way, keep your hands far away from the blade, and never grasp the wood in front of or behind the saw blade. Allow the cut piece to be loose or fall freely—don’t clamp both ends of the wood.

Circular saw with depth of cut set to proper height to cut through plywood.

Circular saw with depth of cut set to proper height.

Step 3: Set Saw Blade Depth

If the saw blade is cutting too deep, it’s more likely to kick back or bind up in the wood, which can be very dangerous.

To adjust the blade depth:

  1. Unplug the saw or remove the battery on cordless models.
  2. Manually retract the blade guard and hold the saw against the edge of the wood.
  3. Loosen the adjustment knob or lever, and adjust the blade depth so the teeth of the blade extend through and no more than ½” below the bottom of the board.
Cutting board with circular saw.

Cutting board with circular saw so the scrap end can fall away.

Step 4: Making the Cut

  1. Always wear eye and ear protection before using a circular saw. Wear an approved dust mask, especially when cutting materials such as concrete, fiber cement, pressure treated wood, and redwood.
  2. Plug in the saw, and move the cord well out of the way of the blade.
  3. Place the saw with the shoe firmly flat against the wood surface, but WITHOUT the blade touching the wood.
  4. Grasp the saw handles with both hands and depress the power buttons (there are usually two for safety, one for your thumb and the trigger) to turn on the saw.
  5. Once the blade is up to speed, align the notch on the saw foot with the cutting line, and move the saw slowly forward. The blade guard will retract automatically as you proceed.
  6. Continue the cut steadily forward, keeping the notch in the foot aligned with the cutting line, until the cut end of the board falls completely away.
  7. Release the trigger and lift the saw away from the cut. Make sure the blade guard is covering the blade and allow the blade to stop spinning before setting the saw down.
Cutting board with circular saw guided by clamped wood fence.

A cutting fence can help keep your saw cutting in a straight line.

More Circular Saw Cutting Tips

Cutting Straight Lines: It can take quite a bit of practice to cut perfectly straight lines with a circular saw. And once the blade is cutting, it doesn’t really respond to steering.

If you see that the cut is straying from the line, stop the saw altogether. Remove it from the cut, realign it with your reference line, and start over.

Multiple saw cuts in board.

Practice cuts in board.

Practice Makes Perfect: Even if you’ve used your saw a million times, it’s still helpful to make a practice cut to remind yourself exactly where the saw blade bites the wood relative to the marks on the cutting shoe, before making the final cut.

The saw shoe has notches or lines to guide you, but sometimes the blade cuts slightly to the right or left of those lines, and sometimes that fraction of an inch matters a lot!

Also, be sure to take the kerf left by the saw blade into account when marking and making the cut.

Saw Guides: For cutting long straight strips, such as ripping plywood, a cutting fence can be a lifesaver.

A fence is a metal accessory that may have come with your saw or can be purchased separately. It attaches to the saw and sticks out sideways, with an adjustable edge that guides the saw in a straight line.

You can also make your own cutting fence, by clamping a straight board to the work. Hold the saw shoe against the fence to keep the saw cutting in a straight line.

Holding an aluminum speed square against the edge of the board and guiding the saw along it a great way to make perfect crosscuts, just be sure to keep your hands out of the way in case the saw kicks back.

Making Beveled Cuts: When making angled or beveled cuts, you may need to lift the blade guard just a little (by grasping the handle, not the guard itself!) in order to get the cut started.

As soon as it’s cutting, let go of the guard to allow it to retract as usual.

Further Information

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