
Carpenter using a brace to drill a hole.

Close-up view of a brace.
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.
The front part of the brace consists of a
chuck spindle with V-shaped brackets or clamps inside. Turning the spindle of the chuck in a clockwise direction tightens the
drill bit in the chuck and turning in a counter-clockwise direction loosens the bit for removal.
In most braces, immediately behind the chuck is a three position
gear release which allows
ratcheting of the handle when in tight spots. Turning the gear release from the center position allows ratcheting the brace in the direction needed. Turning the gear release fully clockwise lets it remove wood in a clockwise direction with the ratchet action going counter-clockwise. Placing the gear release fully counter-clockwise then allows turning the brace and bit in a counter-clockwise direction, usually to remove the drill bit from the hole. The center position of the gear release prohibits the ratcheting effect.
The U-shaped crank has a wooden spindle on it and, along with the top spindle, is allowed to freely turn under the hands without producing wear and tear on the hands (thus, no
blisters).