Circular Saws: The Worm Drive Turns
Circular saws that have worm drive gearing are popular choices in the West and the Midwest, according to Fine Homebuilder magazine . In the East, sidewinders are the circ saws of choice. With the different gear configurations come different strengths (and weaknesses), so many professionals including carpenters pack one or several of each kind of circular saw, to use for different applications.
A sidewinder is basically a direct-drive circular saw with the motor in line with the gearing, so the blade spins faster and the saw is more compact. The blade on a sidewinder is usually on the right (the Bosch CS5 is a sidewinder designed specifically to have the blade on the left). Sidewinders bring higher rpm but lower torque than worm drive construction saws.
Worm drive saws have the motor at the rear of the power tool, with gears oriented at 45° angles. The blade speed is slower but the torque is improved. A heavier and longer saw, a wormdrive model will usually have the blade on the left side.