You'll need:
- each tooth in a different vertex group, you may get away with grouping them by axis, but untested so far;
- duplicate all of your teeth into a new object, delete the newly created vertex groups and assign all of the teeth into a new one, call it
teeth
- This new mesh will be static teeth displayed when the chainsword is holstered or not being used (on the ground, for example); - depending on your model, multiple axes in your Memory LOD. One axis for one direction of travel. Try to simplify your movements, it doesn't need to be perfect to give the illusion that the chainsword is actually "activated".