Abstract: An apparatus for verifying the acceptability of the curvature of kinescope shadow mask after such masks are welded to the support frame includes a fixed member having a surface curved to conform to the curvature of the shadow mask. Sensors are embedded in the curved surface and engage a shadow mask placed on the fixed member. A movable support frame includes support members which support the shadow mask frame above the fixed member while the mask is welded to the shadow mask frame. The sensors also are movable along with the movable support frame. After the welding is completed the support frame is raised to remove the mask from the surface of the fixed member. The sensors are biased and remain in engagement with the shadow mask whereby the sensor readings verify that objectionable deformation of the shadow mask did not occur during the welding operation.