Experience from Measuring the LHC Quadrupole Axes

For historical reasons a pool of equipment is available to measure the axis of the LHC arc quadrupoles. Any of them needs a survey measurement to reference its intrinsic coordinate system to the cryostat fiducials. Up to now 10 quadrupoles have been measured in cold condition. We present our experience, our success next to our failures, explaining the reasons of these failures. This contribution emphasises the day to day problems of such measurements in an ”industrial ” environment and shows simple aids to circumvent them. 1.