*
Normal tolerances are those
can be controlled in casting. **
Premium tolerances require
secondary controls and processes
to comply with
print specifications.
ANGULARITY Angular
tolerance on investment
castings should not be less
than +1/2 °
CONCENTRICITY AND
ROUNDNESS Out
of round is the radial difference
between a true circle and
the cast surface diameter.
The following table is
a guide for out of round
tolerance:
HOLE
DIAMETER
DEVIATION
FROM TRUE
UP
TO 1/2"
+.003
UP
TO 1"
+.005
UP
TO 1 1/2"
+.008
UP
TO 2"
+.010
Concentricity
tolerance varies according
to straightness at about
±.005" per linear inch
of
difference between points
of measure. PARALLELISM AND
PERPENDICULARITY Tolerances
less than within .010 T.I.R.
may require secondary machining. FLATNESS AND STRAIGHTNESS Flatness,
a rough tolerance guide
would be .003" T.I.R.,
(Total Indicator Reading),
for each
1/4" thick section.This variation will be apparent
in surfaces of 1" or
more linear dimension. Straightness,
a constant section will
be axial bow of approximately
.005" per linear inch
under normal tolerance and
about .003" per inch
under premium tolerance.
