A circular saw can make especially accurate cuts, but only if the operator knows how to correctly use the sightlines on the tool’s shoe. Learning about alignment marks, blade visibility slots, and notches can help carpenters and do-it-yourself enthusiasts, alike, achieve better alignment across woodworking projects. Read our guide below to learn how to use the shoe of a circular saw, and watch the video above for tips from This Old House contributor Mark Clement.
Understanding Circular Saw Sightlines
A circular saw’s sightlines guide the blade so that it makes clean, straight cuts. You can find these markings on the saw’s shoe. Circular saws feature several types of sightlines, including those below.
- Alignment marks: Lines or arrows that are etched onto the shoe
- Blade visibility slots: Openings that allow you to see the blade’s position
- Notches: Small indentations on the front of the shoe
Each type of sightline plays a role in keeping cuts on track. Learning how to use each feature will help you to make more accurate and consistent cuts.
Using the Notch Feature on a Circular Saw
The notch on the front of most circular saws aligns the blade with your cut line. This notch extends through the shoe, and allows you to position the saw precisely. Follow the steps below to use the notch:
- Mark your cut line on the workpiece.
- Position the saw so that the notch aligns with your mark.
- Make sure the blade is on the waste side of the line.
- Start the cut, and keep the notch aligned with your mark.
Some saws come with multiple notches that cut different angles, such as 90-degree and 45-degree bevel cuts. This allows you to switch between straight and angled cuts without the need for extra tools.
Setting for Bevel or 90-degree Angle Cuts
Circular saws can make both straight 90-degree cuts and angled bevel cuts. Understanding how to set and use the saw for these different cuts will help you approach different types of woodworking.
90-Degree Cuts
If you’re making standard straight cuts, set the bevel adjustment to 0 degrees, and use the “0” notch. Keep the shoe flat against the workpiece throughout the cut.
Bevel Cuts
If you’re making angled cuts, adjust the bevel setting to the angle you want. Use the appropriate notch, such as “45” for 45-degree bevels, and press the shoe firmly against the workpiece.
Properly Aligning the Saw with the Cutline
To start your cut, place the front of the shoe on the workpiece. Align the appropriate notch with your cut line, and make sure the blade does not touch the workpiece. Start the saw and allow it to reach full speed.
Maintaining Alignment During the Cut
Keep a steady, controlled pace as you work through the cut. Use the notch as a guide for the first part of the cut, then transition to sighting directly down the blade. Make sure the blade remains on the waste side of the line.
Common Alignment Mistakes
Avoid the common errors below as you work.
- Failing to maintain a consistent cutting speed
- Neglecting to account for blade thickness
- Neglecting to keep the shoe flat against the workpiece
- Rushing the alignment process
Advanced Sightline Techniques for a Circular Saw
As you get more comfortable with sightlines, you can incorporate advanced techniques into your cuts. Experienced users often use multiple reference points, such as the notch for initial alignment and the side of the blade for finer adjustments. You must account for the thickness, or kerf, of the blade.
If you’re working in a tight space or a space with little visibility, mark your cut line clearly, use a guide for longer cuts, and trust the feel of the saw against the guide to stay on track.
Maintaining Your Circular Saw for Accurate Cuts
Keeping your circular saw in top shape is the best way to get clean cuts. Start by cleaning the saw’s shoe to remove dust and grime. Clear out any buildup in the notches and alignment marks with a soft brush or mild solvent.
Regularly inspect the saw for any damage, such as bent shoes or worn-out markings, and secure all of the saw’s parts. Replace dull blades and correctly align them.
Keep safety features such as the blade guard in good working order. Lubricate the guard pivot, and check the power cord for wear.
Working with Different Materials With a Circular Saw
Different materials may require different approaches to using the saw’s sightlines. For example, use a fine-tooth blade when cutting plywood to avoid tear-out, and make sure to support the entire sheet. Cutting hardwood requires more power and a blade that’s designed for the material. If you’re working with metal, switch to a metal-cutting blade, and use cutting oil to reduce friction.
Each material demands specific techniques, so adjust your speed, pressure, and sightline use accordingly.