Velocity Ratio and Centre Distance:
While worm makes one rotation, the angle turned is equivalent to 2π. At the similar time, angle turned by the worm wheel shall be (lead 'L'/Pitch circle radius).
∴ Velocity Ratio (VR) =
From Section 9.6.1, by Equations. (9.10), already it is known that
Centre Distance (C) =
. . . (9.15)