If you’re running a pipe or installing a doorknob, you need a hole saw. These drill-mounted cutters are made of carbon steel or bi-metal (high-speed steel edge and flexible, break-resistant backing steel). Carbon steel saws cut wood only, while pricier bi-metals also puncture the metal of, say, an exterior door’s shell.
Lenox’s bi-metal hole saws have two features I’d like to see on all hole saws: (1) Stepped slots make prying out stubborn waste plugs easier, and (2) a quick-release arbor avoids a nasty problem with threaded arbors: The saw can torque the threaded connection so tight that it’s very difficult to unscrew.
Tips for using hole saws
Go slow: When a hole saw binds, it can send a tremendous amount of torque back through the drill—and a bucking, spinning drill can easily injure you. Use a firm two-handed grip and drill slow and straight. Withdraw the saw often to clear sawdust from the kerf.
Cut smooth: Hole saws drill cleanly going in, but can tear out on the backside. With doorknob holes, the escutcheon doesn’t always cover the damage. Drill just until the pilot bit exits the back, then finish the hole from the other side
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