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I am ready to buy a new circular saw...What is the difference between a Worm-drive and Direct-drive?

The biggest difference between the two is how the power is transferred from the motor to the blade. A worm-drive saw gets its name from the gearing that turns the blade. A worm gear on the end of the motor shaft drive a gear on the blade arbor. To prevent overheating and limit the amount of wear the gears run in a crankcase filled with lube oil, much like the differential on a car. Doing this allows engineers to gear down the saw so that it get loads of torque without the blade stalling in wet or dense lumber. Framing carpenters love them because you can cut knotty, green or pressure treated lumber all day, day after day.

I think most carpenters agree that a worm-drive saw is also easier to handle on the job site. You push the machine out and across, where as a direct drive saw is handled from above the saw – requiring the user to push down, out and across the lumber.

Direct drive saws are driven by helical gears that step down the speed of the motor. They lack the torque of their worm-drive cousins.

If you are just going to use the saw for ripping sheet goods or cross-cutting 2Xs – save your money. If on the other hand, you are building a house – a worm-drive is the way to go.

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