The SJ-210 and SJ-310 cannot measure the depth of a deep scratch or gouge.
The SJ-210/310 detector is supported by a skid that moves with the stylus to trace the surface.
The skid can bridge over a deep scratch or gouge restricting the ability of the stylus to follow the full profile of the surface beneath it.
This type of measurement might be possible using the skidless styli found in the SJ-410 together with "simple contour analysis feature"
Contact Mitutoyo via your authorised Mitutoyo dealer to discuss further.