How to Choose a Circular Saw

Safety First: Before using any circular saw, always wear safety glasses — circular saws kick up a lot of sawdust and wood chips. And never pin back the blade guard. Even after you release the trigger, the blade can still be spinning. If you set the saw down with the guard pinned, you risk a serious cut. As the This Old House team advises: leave the guard alone.

Steps:

1. Tom praises the versatility of circular saws and shows off a variety of them.
2. Tom also shows off a worm-drive circular saw. This saw offers good balance and more power. It also has the handle behind the blade for better control of the saw.
3. Tom demonstrates the circular saw most commonly used, the sidewinder, electrical version.
4. Tom admits while circular saws vary in quality, much of the experience boils down to the quality of the blade.
5. Tom illustrates the difference between blades. Blades with a lot of smaller teeth are typically used for a finer cut. Less teeth, but larger blades are used for framing and give you a rougher cut.
6. Diamond-tipped blades can be used to cut masonry.
7. Tom says each circular saw comes with a knob that can adjust the height of the blade. That can determine how deep you would like your cut to go.
8. Tom says there is also a knob that adjusts the angle of your cut up to 45 degrees.
9. Tom illustrates the use of a 45-degree angled cut. Those pieces can come together to form a perfect 90-degree angled corner.

Expert Insight: Tom Silva, This Old House general contractor, stresses the importance of power when choosing a circular saw: “When the motor slows, the blade heats up and dulls quickly.” He warns that this not only produces a poor cut, it’s dangerous because the blade can climb out of the kerf and push the saw back toward the user.