Blade Size and CapacityCircular saws are sized based on the saw blade diameter, with 7-1/4" being the most common. The blade depth can usually be adjusted, but you can't put a large diameter saw blade in a circular saw made for a small diameter blade. It's important to check the capacity of the saw, or the maximum wood thickness the saw can cut through, to be sure the saw will cut the types of wood you intend to work with. A saw with a 1-1/2" maximum capacity will not work if you want to cut 2x4 lumber.

Circular Saw Blade Types

The size and shape of the arbor, or spindle that holds the saw blades, will determine the type of saw blades you can use with a circular saw. Many circular saw arbors are almost universal, but some take specialty blades that can be harder to find. Before buying a circular saw, check to see what diameter and style of saw blades it takes, and be sure those saw blades are available to you locally.

Take the Circular Saw for a Test Drive

A circular saw should feel sturdy and well-built. While some plastic parts are OK, a predominantly plastic saw may not hold up for many years. Circular saw handles are important for stability and accuracy, so be sure you can comfortably hold the saw by the handles and control the movement. The riving knife, or the thin, curved piece behind the blade, should be centered behind the blade and needs to be sturdy, as it keeps the blade from being pinched during use.

Safety Blade Guard

The blade guard minimizes the chance that a running saw blade will cut something other than its intended wooden target. During your circular saw test drive, take note of how the blade guard operates. Look for a blade guard that works smoothly and doesn't feel awkward. Sometimes blade guards don't raise automatically when you're making certain types of cuts, so be sure you can easily raise the blade guard manually if necessary. Never remove the blade guard from your circular saw.

Adjustments Should Be Easy and Accurate

There aren't many adjustments to be made on a circular saw, but you should check to see that the blade depth stays at the correct setting once it is locked in place. Also check that it is easy to change saw blades, and the blades lock into place sturdily. If you intend to make angled cuts, look for a tilting base that locks tightly at different angles to guide your cuts.

Horsepower and RPM

As with any power woodworking saw, you should choose a circular saw with horsepower and RPM that match the type of work you intend to do. If you plan to cut large, thick boards or make a lot of long cuts, don't buy the least expensive, low-horsepower circular saw you can find. An under-powered saw can cause heat buildup for the blade, leading to worn out blades and possibly to a dangerous saw kickback effect.

Sidewinder or Worm Drive?

The sidewinder style circular saw, where the motor sits alongside the blade, is the most popular and can be had for a fairly reasonable price. If you need a lot of power and are willing to shell out more money, look for a worm drive circular saw, where the motor is in line with the blade. For general wood shop use, a sidewinder is probably sufficient for most projects.