Problem for making mesh in GAMBIT
 

Hello.... I am planning to make mesh annular volume with a helical tooth. It is like labyrinth seal. These seals are essentially a tooth on stator labyrinth seal where the grooves are a continuous helical cut like a thread. The problem is to make mesh in gap between the inner and outer cylinder. The gap is 0.002 in and the diameter of cylinder is 4.6 in. It is possible to make mesh each volume but after uniting annular volume and a helical tooth of labyrint seal volume, spliting them and then making mesh them, I cannot get meshing geometry.

I need help.....