The best transmission decision is when large transmission reduction is essential. A worm equipment is comparable to a helical equipment with a throat cut to increase the outer diameter of the wheel. The throat makes it possible for the worm equipment to wrap completely about the threads of the worm. By cutting the threads on the worm fairly than the teeth, and by altering the amount of threads, diverse ratios can be achieved with out altering the mounting arrangement. A unique feature of worm gears and worm equipment assemblies is their capacity to avoid reverse rotation.