Sidewinders vs. worm drive circular saws
What's the difference?
There are two kinds of handheld circular saws, and the difference boils down to the way power from the motor is delivered to the blade. So-called sidewinder saws have the motor either on the left- or right-hand side of the blade, hence the name. Worm-drive saws, on the other hand, transmit power 90º in a way that places the motor behind the blade. This set-up makes for a heavier, narrower saw that also spins blades more slowly because of the gearing-down action. Typical worm-drive saws spin at about 4,400 rpm, compared with almost 6,000 rpm for sidewinders. Slower speed translates into more torque for tougher cuts.
Sidewinder saws are lighter, but the location of the side-mounted motor can make it difficult to see the cut line. Models with blades located to the left of the motor are easier for right-handed users. The opposite is true for lefties. Generally, sidewinder models are favoured in eastern Canada, while carpenters out west tend to choose worm-drive saws more often.
The world’s first handheld circular saw was a worm-drive model made in 1924; the Skil Model 77 that’s still available today is a direct descendent of this first machine. The term worm drive refers to a particular kind of spiral-shaped, internal drive system. For more than 60 years, worm-drive saws were the only non-sidewinder models you could get, so the name became generic. These days, several manufacturers offer gear-drive saws that use hypoid gears; although, the old worm-drive name still gets used. The direct-drive sidewinder saw was invented in 1928 by Porter-Cable engineer Art Emmons as a way to get around patents protecting the gear-drive concept.