On a worm drive the second bushing of the worm is replaced with an oblique thrust surface or made to follow a path constraining the worm to move closer to the gear as it is pushed forward by the gear itself as a result of the torque applied by the load. The oblique forces thus generated push the worm towards the gear and constitute a meshing force that makes the system self-adjusting with zero play between the parts, eliminating backlash and dependency from manufacturing tolerances and from the effects of wear. It also results in freedom of movement between worm and gear allowing them to be easily disengaged. The meshing force is predictable and independent from the deformability of the parts, and makes possible the use of stronger triangular teeth, allowing much higher gear ratios.