<p>A plurality of gauges are provided with each gauge including a horizontal arm, a vertical elongated measuring member guidingly supported from one end of the arm for adjusted vertical shifting relative thereto and first lock structure operatively associated with the arm and the measuring member for releasably locking the measuring member in adjusted shifted position relative to the arm. A vertical standard is provided including mounting structure supporting the arm from the standard for vertical shifting therealong with the arm disposed at right angles relative to the standard. Second locking structure is operatively associated with the arm and the standard for releasably locking the arm in adjusted shifted position reltive to the standard and levelling structure is carried by the arm for indicating when the arm is precisely horizontally disposed. A base is carried by the lower end of the standard for support of the standard from a floor surface and the base defines a pair of downwardly facing support surfaces spaced along a horizontal path normal to a radius of the center axis of the standard and spaced outwardly from the axis. A third downwardly facing and vertically adjustable support surface is defined by the base and disposed on the side of the center axis remote from the aforementioned path and the mounting structure supporting the arm from the standard includes structure operative to allow at least 180.degree. angular displacement of the standard about its center axis relative to the arm.</p>
