When we ask whether to buy a worm-drive saw or a circular saw, what we’re really asking is whether to buy a worm-drive saw or a sidewinder saw. This is because worm drive saws and sidewinder saws are both circular saws. They are just two different types of circular saws.
What separates those two classes of circular saws is the location of the blade in relation to the motor.
The question of whether to buy the one or the other ultimately comes down to what you need to do.
Worm drive saws were invented in the early days of last century after a Louisiana man saw that people were having difficulty cutting down sugar cane with machetes. The worm-drive saw was his way to help those workers do their work faster and more efficiently.
Worm-drive saws position the blade in front of the motor and turn the blade by way of a threaded worm drive that runs down the shaft. The worm’s threads gears that are connected to the blade arbor in front of the motor. This turns the blade with more torque, making it easier to cut dense, difficult materials, like knotted hardwood. Or as in the old days, sugar cane.
A sidewinder saw gets its name from the fact that the blade sits next to the motor. It turns it directly rather than have gears do it. It can also turn at a much higher RPM rate than a worm-drive saw.
Sidewinder saws don’t have the cutting torque of a worm-drive saw, but they are also about half the price. Because there are no gears for a motor’s energy to be lost, they also tend to spin quite a bit faster than worm-drive saws.
That’s really about as complicated as it gets. A worm-drive saw is called so because it has a threaded worm in front of the motor that turns gears, which turn a blade sitting in front of the motor. It cuts with much greater torque than a sidewinder.
A sidewinder is called that because it sits next to the motor. It can’t quite spin up the torque, but it will spin at much higher RPMs than a worm-drive circular saw.
Carpenters and other professional woodworkers prize worm-drive circular saws for their higher torque, which gives them better power in cutting through difficult pieces of wood. They also tend to cut a little more accurately than do sidewinder saws.
The catch is that worm-drive saws are really expensive compared to regular sidewinder saws, sometimes double the sticker price. They are also longer and narrower than sidewinder saws, which tend to be squatter and more compact.
That doesn’t necessarily price them out of range for home hobbyists and DIYers. It’s just for most people with a normal workload, a sidewinder saw is more than adequate to handle the jobs.
Make your choice based on your needs.