Gauges. For specifying the vernier height gauge, one has
to specify clearly the range of measurement, the type of
scales desired, and any particular requirements in regard
to the type of vernier desired. Generally, all the parts of
the height gauges are made of good quality steel, or stain-
less steel also in certain cases. At the time of fabrication,
the blanks for all height gauges are suitably heat-treated
so as to remove any stresses resulting from possible cold
working. The underside of the base and the faces of the
measuring jaw and scriber are hardened to about 700 HV
(58 RHC) for good quality steel and up to 650 HV (56 RHC)
for stainless steel. In selecting a suitable high carbon
stainless steel to give a hardness of not less than 650 HV,
a balance should be drawn between hardening qualities
and resistance to staining, because a steel which gives a
high hardness number is likely to have low acid resisting
qualities. The various parts and the nomenclature of the
height gauge are illustrated in Fig. 2.102.