A measuring device includes a base, a holding member mounted to the base and having a notch for holding a cylinder, a guide rod connected to the base and defining an axial direction parallel to an axial direction of the cylinder, and a gauge mounted with the guide rod and defining a measuring direction...http://www.google.co.uk/patents/US7748134?utm_source=gb-gplus-sharePatent US7748134 - Measuring device for cylinder
