Worms and worm gears are used to power right angle, nonintersecting shafts. In normal applications the worm gear is driven by the worm. The most popular use of worms and worm gears is in applications where high ratio speed reduction is desired in a relatively limited space. They are also used in applications where high resistance to the worm gear shaft reversing and driving back through the worm is desired. Martin Worm Gear, Reborable Web, 1.25 to 1.815 in Bore Dia, 12.373 in Outside Dia, Single Number of Threads, 72 Teeth, 6 Diametral Pitch, 12 in, 1 in Face Width, Right Hand Direction of Rotation, 3 in Hub Dia, 1-1/4 in Hub Projection, 2-1/4 in Overall Length, 14.5 deg Pressure Angle, Cast Iron