Best choice of gearing when high drive decrease is required. Worm Tires resemble spur gears by adding a throat cut into the O.D. of wheel. The throat permits the worm wheel to fully envelope the threads of the worm. Threads, not really tooth are cut on the worm, and by adjusting the amount of threads, different ratios may be accomplished without altering mounting arrangements. A distinctive feature of Worm and Wheel assemblies is 
certainly their ability to Worm wheel gear prohibit back driving
Pitch: 16 to 64 DP and 1.5 to .5 MOD
Materials: Brass for Worm Gear and Stainless Steel for Worm
Single, Double or Quad Start