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Circular Saws

Sometimes you just feel the need to saw a plank of wood in half. Nothing will be able to do this for you faster or more efficiently than a circular saw. Circular saws  outpace traditional handsaws by far, and no handyman's workshop is complete without one.  However, as a power tool, a circular saw is also inherently more dangerous than any hand powered saw. Proper caution and respect should be part of your tool kit. Once your have mastered the basics of circular saws, you will find that it is an extremely versatile tool -- depending on the type of blade, circular saws can cut lumber, plywood, posts, plastic, tiles and metal.

Circular saws vary widely in price from as little as £10 to as much as £500. Up to a point, you get what you pay for -- a £10 saw won't have all the nice features, won't be as sturdy or well-designed, and may die on you fairly soon. If you plan to use your saw for more than very occasional projects, spend a few extra quid on a good tool that won't snuff it in the middle of sawing something.  

Circular Saw Characteristics

The motor in these saws can drive the wheel in two different ways.

  • A sidewinder  drive has the blade mounted directly on the drive shaft of the motor.
  • In a worm drive,  the blade is driven indirectly by a series of worm gears.
    • Worm drive saws have more torque and are more powerful tools.

Circular saws also come in corded   and cordless  versions.

  • New battery technology has increased the power of cordless saws without significantly increasing the weight.
  • Look for lithium-ion or nickel-metal hydride (NiMH) batteries.
  • If you get a cordless, get at least 18V. 24V or 28V batteries are preferable.
  • If you get a corded, get at least 15A.

A standard circular saw  is a right-handed sidewinder saw, with a left-handed motor and a 7.25" blade, but there are lots of factors to consider when buying a circular saw.

Important Features

The four most important features are:

  • Ergonomics -- will it be comfortable for an extended period of use?
  • Sightlines -- can you see the leading edge?
  • Depth and bevel settings -- can they be adjusted easily?
  • Base and blade guard -- is the baseplate sturdy and inflexible?

Here are a few other things to consider.

  • Blade Capacity is the maximum depth a saw can cut; the longer the blade (measured by diameter), the deeper the cut.
    • Generally a 6" blade or larger can cut through a 2" piece of lumber at a 45-degree angle in one pass.
    • Remember that the bigger blade, the more power required to turn the blade.
    • Most home users don't need anything larger than 7.5"; however, a 6" blade might not be sufficient for all tasks.
    • 7-7.5" is the recommended range.
  • Amps (A), Volts (V) and Horsepower (HP) all measure different aspects of the saw's cutting power.
    • Corded saws are rated in amps. 15A is the minimum amperage recommendation for corded saws
    • Cordless saws are rated in volts. 18V is the minimum recommeneded voltage for cordless saws.
  • Blade Guard protects you from the blade!
    • The action should be smooth and reliable, even when the bevel is set to an acute angle.
    • You'll also want a bevel that extends past 45 degrees, since some angles that should be 45 degrees might actually be off by a few degrees. You might want the option to cut at a bigger angle to adjust if this is the case.
    • Make sure to test this with the blade off and on; malfunctioning blade guards are the most common reason for recalls of circular saws.
  • Electric Brakes reverse power in the motor when the trigger is released, stopping the blade in 2-3 seconds.
    • Models without this feature may take up to 12 seconds to stop the blade.
    • This is highly recommended for all circular saws as a safety measure.
  • Ribbed Magnesium Base Plates give the best strength-to-weight ratio. A baseplate that's too flexible can cause inaccurate cuts and is easily damaged.
    • For long, accurate cuts you should adjust the baseplate so it's perpendicular to the blade with the edge of the work parallel to the blade.
  • Safety Lock-off Switches prevent accidental starts.
  • Depth Adjusters are for safety purposes and cutting smooth, clean lines.
  • Shaft Locks keeps the shaft and blade still when changing out the saw blade.
  • Other Considerations:
    • Miter Adjustment: for adjusting bevel angle.
    • Dust Collection Port: blows wood chips to the sides and lets you hook up an industrial vacuum for easier clean up.
    • Rafter Hooks: may be convenient for storing the saw.

Circular Saw Blades

  • Steel: standard blade, good for cutting softwoods but dull quickly when cutting hardwoods.
  • High-speed Steel: better than standard steel for hardwoods.
  • Carbide: has carbide tips attached to blade teeth. They're more expensive but much more durable than either of the above.
  • Tile Cutting: for cutting tiles. High-quality blades have diamond-tipped teeth.
  • Masonry Blades: For cutting concrete, brick, cinder block and other masonry materials.

Major Manufacturers

Related Guides and Products

Power Drills

Mitre Saws 

Woodworking Routers

Nail Guns 

Wet/Dry Vacuum

External Links

  • DIYData.com -- buying guide with a labelled illustration so you can get to know the parts of a circular saw!
  • DIYFAQ.org.uk -- a good buying guide.