A brace or brace and bit is a hand tool used to drill holes, usually in wood. Pressure is applied to the top and the tool is rotated with a U-shaped grip. The U-shaped part is a kind of crankshaft. It gives the brace much greater torque than other kinds of hand drill; a brace can be used to drill much wider, and deeper, holes than can a gear-driven hand drill.

Brace and Bits

A brace or brace and bit is a hand tool used to drill holes, usually in wood. Pressure is applied to…

It consists of a steam cylinder and piston and its rod, and to the rod is firmly secured a steel rock-drill. The cylinder is supported upon a heavy tripod that may stand in any position and present the point of the drill in any direction. The steam or compressed air is conveyed to the cylinder through a hose, and when ready for work it delivers its tremendous thundering blows upon the rock in rapid succession.

Pneumatic Rock Drill

It consists of a steam cylinder and piston and its rod, and to the rod is firmly secured a steel rock-drill.…