... for worm gears to have reductions of 20:1, and even up to 300:1 or greater.2,Many ... the gear tries to spin it, the friction between the gear and the worm holds the worm in place.3, ... differential, which is used on some high-performance cars and trucks. Transmission typesZKnumber of teeth10-120Tooth shape Angle15°Worm ... 1 10089-88diameter20-600materialsCopper alloy, zinc alloy Worm And Gear china supplier