A clamp apparatus includes a main frame, at least one table attachment bracket, a pair of adjustable clamping members, at least one measurement member, at least one vice attachment bracket, a catch tray and a shield member. The clamp apparatus preferably attaches to any existing drill press table, offers multiple clamping solutions for a work piece and provides a stable tabletop for the work piece.

A clamp apparatus includes a main frame, at least one table attachment bracket, a pair of adjustable clamping members, at least one measurement member, at least one vice attachment bracket, a catch tray and a shield member. The clamp apparatus preferably attaches to any existing drill press table, offers multiple clamping solutions for a work piece and provides a stable tabletop for the work piece.

An electric tool includes an output part that comes into contact with a working target to process the working target, a motor that drives the output part, and a sensor that measures capacitance of a metal part comprising the output part. The electric tool detects a foreign object based on a change in the capacitance measured by the sensor.

An electric tool includes an output part that comes into contact with a working target to process the working target, a motor that drives the output part, and a sensor that measures capacitance of a metal part comprising the output part. The electric tool detects a foreign object based on a change in the capacitance measured by the sensor.

Provided is a liquid circulation system including: a shield that covers a boring area of a workpiece in which a hole is bored with a tip of a bit attached to a boring device; a liquid container that holds a liquid; a liquid feeder that forcibly feeds the liquid held in the liquid container to the tip; and a liquid collector that forcibly collects a liquid suspension from an area shielded by the shield and returns the liquid suspension to the liquid container. The liquid circulation system is able to ensure liquid circulation while reliably preventing backflow of the liquid suspension.

Provided is a liquid circulation system including: a shield that covers a boring area of a workpiece in which a hole is bored with a tip of a bit attached to a boring device; a liquid container that holds a liquid; a liquid feeder that forcibly feeds the liquid held in the liquid container to the tip; and a liquid collector that forcibly collects a liquid suspension from an area shielded by the shield and returns the liquid suspension to the liquid container. The liquid circulation system is able to ensure liquid circulation while reliably preventing backflow of the liquid suspension.