When experiencing a lack of repeatability using a laser system, check the components for looseness:
- Brackets: Make sure that they are rigidly attached to the shafts (or solid coupling hubs). The surface imperfection where the brackets are mounted plays no role provided the shafts are rotated and the bracket is firmly attached to the surface.
- Risers: Most brackets systems will have risers (support posts) attached to them to mount components. Make sure they are firmly attached to the brackets.
- Lasers, Receivers, Prism: Also make sure they are firmly attached to the risers.
- Brackets rubbing: the brackets and everything they support must not touch or rub on any stationary part during rotation.
Looking out for these simple little things can save you many headaches during your alignment job.