Radius Gauges (Metrology)

2.22.
Wherever two surfaces meet, a radius is generally given to avoid stress concentration. The
radius also plays an important role in case of heat treatment of parts. Thus the proper radius must
be maintained and for checking it, radius gauges
are employed. If the curved surface is external, i.e.
male radius it is simply called a ‘radius’. If curved
surface is internal, i.e. female radius, it is called a
‘fillet’. Radius gauges consist of sets of blades on
each of which is stamped the corresponding radius.
On one side we have external radius and on the
other side internal radius, so that it may be
suitable for fillets as well a radius. Radius gauges

Fig. 2.82. Fillet or Radius Gauges.
are used with proper light, placing the work to be gauged between light source and eye. It is only
with the passage of light between gauge and work that the radius can be gauged properly.
Fillet or Radius Gauges. It contains external and internal radius on each leaf permitting
both concave and convex surfaces to be measured. The leaves are specially shaped so that they can
be used in any position at any angle to measure fillets and radius in corners or against shoulders
(Refer Fig. 2.82).