Case-Springs—The springs which cause the outer bottom of a watch case to fly open when the lock spring is released.
Center of Gyration—That point in which the whole mass of a rotating body might be concentrated without altering its moment of inertia.
Center of Oscillation—That point in a pendulum at which, if the whole mass of the pendulum were collected, the time of oscillation would be the same.
Center Seconds or Sweep Seconds—A long seconds hand moved from the center of a watch dial, as are the minute and hour hands.
Center Staff—The arbor attached to the center wheel which carries the minute hand.
Center Wheel—The wheel in ordinary clocks and watches placed in the center of the frame on whose arbor the minute hand is carried. It is intermediate between the barrel and the third wheel.
Chamfer—To cut away to a bevel the right angle formed by two adjacent faces as of a jewel or stone. It is also occasionally used to signify channeling or grooving.
CHAMFER