How to select a circular saw
Circular saws come in a variety of sizes and configurations. Here are some tips on how to select a circular saw for whatever job you are doing.
While circular saws come in a variety of sizes, for general use, the 7¼- and 5⅜-inch blade saws are generally ideal. And, while once, given the power requirements needed to rip through plywood and 2x4s, a corded circular saw was required, today’s trending cordless circular saws can handle the work load and run all day on a single charge.
Direct drive or worm?
With corded saws, there are two basic configurations:
- Direct drive – the motor is perpendicular to the blade mounted on the end of the motor shaft. For most purposes, direct drive is more than adequate. The saw is a bit smaller and lighter. And it’s usually cheaper.
- Worm (or hypoid drive) – the motor is parallel to the blade and uses a gear set to turn the drive through a right angle. Since there are gears involved, this style can bring more torque to the cut. Geared saws are great for framing, as the weight of the saw in a downward cut actually advances the blade through the wood.
Circular saw features
Now you have a saw that can spin the blade at 5,000 rpm or so. But what else can you expect when you select a circular saw?
The base plate can be adjusted for depth of cut or tilted to enable an angled cut – typically 45 degrees for a mitered joint. The plate can be clamped with a screw or a lever – for speed of adjustment, a lever is better – and some models have a scale so you can quickly read depth and angle of cut
Footplates have a notched leading edge to guide the saw along a line. Some have a laser to guide the saw along the cutline, though these are of little use if the tool is being used in bright sunlight.
A shaft lock makes it easier and quicker to change the saw blades.
The blade does the real work and the size of the blade determines the maximum thickness of material the saw can cut in a single pass. Both 5⅜- and 7¼-inch saws will cut a 2-inch piece and if you’re cutting 2x4s either size can get the job done.
However, only the 7¼-inch saw can cut a 45-degree cut in a single pass, making it the more useful all-purpose tool
When it comes to select a circular saw, many contractors prefer to have a corded saw for bigger jobs that benefit from the power afforded by 110 volts and a smaller, lighter 18V cordless 5⅜-inch saw for ease of use and for getting into tight spaces without the restriction of a cord.
Blades come in four basic categories: steel, hardened steel, carbide tipped and ceramic. For a contractor, the carbide tip is the best all-round choice, but a ceramic blade is necessary for cutting stucco. A diamond edged blade can be used to cut tile.
To cut wood, generally, the greater the tooth count the slower the progress but the finer the cut. Again, a good all-round compromise is the 24-tooth blade, and a thin kerf (width of tooth) is good because it doesn’t remove so much material and so it works faster. This blade will make short work of cross-cuts.
For ripping down a board parallel to the grain, fewer teeth gets the job done quicker and an 18-tooth blade is preferable. For finer finished cuts, a 40-tooth blade is the way to go.
–By Steve Sturgess, stevesturgess.com