US Patent 7243435 Level device and method of calibrating a level vial

The level device includes a level body having a pair of orthogonal reference surfaces. A vial carrier on the level body holds the level vial such that it can be calibrated with respect to the reference surfaces by rotation about a pair of orthogonal axes, each of the orthogonal axes being perpendicular to the direction of elongation of the level vial. Adhesive fixes the position of the level vial with respect to the vial carrier and fixing the position of the vial carrier with respect to the level body. The vial carrier includes a vial support and a pivot for engaging the level body. When the vial is calibrated, it is rotated about a first axis perpendicular to the direction of elongation of the level vial, and about a second axis perpendicular to the direction of elongation of the level vial and perpendicular to the first axis.