The height gage scriber must be checked against the reference surface before attempting to make any height measurements of layouts. Clean the surface of the layout table and the base of the gage. Slide the scriber down until it just rests on the reference surface. Check the alignment of the zero mark on the vernier scale with the zero mark on the beam scale. The two marks should coincide exactly. Hold the height gage base firmly against the reference surface. Be sure that you do not tilt the base of the height gagr by sliding the vernier slide past the zero point on the beam do not coincide after the scriber has contacted the reference surface, an adjustment of the vernier scale is required.