PRECISION MEASURING AND GAGING - OD1642 - LESSON 1/TASK 2
FIGURE 31.
USING PRECISION GAGE BLOCKS.
CAUTION
Do not leave blocks wrung together for long periods of
time since the surfaces in contact will tend to
corrode.
(d) Ordinary changes in temperature have a significant effect on
the measurements made with precision gage blocks.
The standard measuring
temperature is 68ƒF, which is just a little lower than the average
temperature in most shops. Since the room temperature affects the work as
well as the block, the expansion in the work will be matched in most cases
by a similar expansion in the block.
The coefficient of expansion of
several metals and blocks are listed below:
45
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