SM0486
(4) Scale shape error.
a. Scale shape error is a deviation in linearity which may vary
in value and create a plus and/or minus indication at various points over the
entire scale range, even though the indication at the beginning and end of the
scale is correct.
Figure 11 illustrates a gage with scale shape error.
Scale
shape error is a function of the length and position of the linkage, which connects
the spring to the sector.
Figure 11.
Scale shape error-dial example
b. Correction for scale shape error involves rotation of the
entire movement, the locking screws of which are usually located at the rear of the
gage.
As shown in Figure 12, units that do not provide the movement rotation
feature may provide for adjustment in the length of the link which has essentially
the same effect as rotation of the movement. Gages having lesser accuracy usually
do not provide any means of scale shape adjustment.
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