Abstract: An erosion gauge for measuring a chord length of an eroded turbine blade in a steam turbine that may include: a jaw that includes a lower jaw that includes a lower jaw surface and an upper jaw that includes an upper jaw surface such that the lower jaw surface and the upper jaw surface oppose each other; a sliding scale that connects the lower jaw to the upper jaw, wherein a first end of the sliding scale is fixed to the lower jaw and a second end of the sliding scale slides through the upper jaw such that the distance between the lower jaw surface and the upper jaw surface may be varied; and an electronic depth gauge that determines the distance between the lower jaw surface and the upper jaw surface. The lower jaw surface may include a valley insert.