A method and apparatus for locating improperly positioned or bent rolls among a set of rolls which define a confined path of travel for a workpiece, particularly useful for checking a straight or curved roll-rack of a continuous-casting machine. The apparatus may be propelled through the path defined by the rolls by any suitable mechanism. For example, as applied to a roll-rack, the apparatus may be attached to the upper end of a starter bar and propelled with the bar through the rack, or the apparatus may be suspended from a hoist and pulled through the rack. The apparatus includes a housing and means within the housing for measuring the gap between work-engaging faces of the rolls and/or, when used with a curved roll-rack, means for measuring the angular relation of adjacent bottom rolls. The latter measurement is used in determining whether the work-engaging faces lie on arcs of the intended radii. Bent rolls are located by observing different measurements when the apparatus is moved in opposite directions through the path of travel.