Fig. 3.
Fig. 4.
Fig. 5.
When the wheel has its teeth arranged at an angle to the shaft, as in [Fig. 2], it is termed a bevel-wheel, or bevel gear; but when this angle is one of 45°, as in [Fig. 3], as it must be if the pair of wheels are of the same diameter, so as to make the revolutions of their shafts equal, then the wheel is called a mitre-wheel. When the teeth are arranged upon the radial or side face of the wheel, as in [Fig. 4], it is termed a crown-wheel. The smallest wheel of a pair, or of a train or set of gear-wheels, is termed the pinion; and when the teeth are composed of rungs, as in [Fig. 5], it is termed a lantern, trundle, or wallower; and each cylindrical piece serving as a tooth is termed a stave, spindle, or round, and by some a leaf.
