2 step plastic plus one Worm gear

grabcad

This was really a Challenge.I tried a lot of combinations.. really a lot.My first goal was to create a gear with no lubrication. but the temperature changes in the construction would increase the backlash to much. and the housing would not be able to withstand the torq forces.Second goal was to use one step worm gear with a reduction of 40 and plastic gear outside the oil box. combined gear ratio 712. The efficiency of the worm gear turns out to be 0,26 way higher then i had expected. So the solution failed. There is a lot of calculations, hope someone can use the material to something. :)