Power tool basics
Power tool basics
Corded vs. cordless, brushless motors, clutches and chucks in plain English.
Power tool basics, in plain English
Most of the confusion in the tool aisle comes down to a handful of words printed on the box. Here's what they actually mean before you spend the money.
Corded vs. cordless
Cordless wins for convenience and covers most jobs. Corded still wins for long runs, big saws and anything you'll lean on for hours.
Brushless motor
No carbon brushes to wear out — more runtime per charge, more power, less heat. Worth it on tools you'll use often.
Drill vs. driver
A drill has a keyless chuck and a clutch for holes and precision. An impact driver takes 1/4" hex bits and hammers out torque for long screws.
Hammer drill
Adds a rapid forward tapping action for block, brick and concrete. Different from a rotary hammer, which is heavier duty.
Clutch settings
The numbered collar behind the chuck. Lower numbers stop the drill sooner so you don't strip the screw or sink it too deep.
Chuck size
3/8" handles most homeowner bits; 1/2" takes bigger shanks like spade and hole saw arbors.
Amp-hours (Ah)
Fuel tank size, not power. A 5.0Ah pack runs about twice as long as a 2.0Ah — and weighs more.
Kerf
The width of material a blade removes. Thin-kerf blades cut faster on smaller saws and waste less wood.
Arbor
The shaft a blade or wheel mounts on. Match the arbor hole to the tool — 5/8" on most circular saws.
Unplug a corded tool — or pull the battery — before you change a blade, bit or disc. It takes two seconds and it's the single most common way people get hurt.