PRECISION MEASURING AND GAGING - OD1642 - LESSON 1/TASK 2
a human hair divided by 1,500 equals 0.000002 of an inch.
The degree of
accuracy applies to the thickness of the gage block, the parallelism of the
sides, and the flatness of the surfaces. The gages are lapped so smooth and
flat that when they are "wrung" or placed one on top of the other in the
proper manner, one cannot separate them by pulling them straight out; they
have to be slipped to the side and then off.
A set of gage blocks has
enough different size blocks that any measurement can be established within
the accuracy and range of the set.
As one might expect, anything so
accurate requires exceptional care to prevent damage and to ensure continued
accuracy.
A dust-free temperature-controlled atmosphere is preferred.
After the gage blocks are used, each block should be wiped clean of all
fingerprints and coated with a thin layer of white petroleum to prevent them
from rusting.
FIGURE 30.
GAGE BLOCKS.
(c) Gage blocks are used for various precision measurements.
Before using a set of new gage blocks, remove the coat of rust preventing
compound with a chamois or a piece of cleaning tissue, or by cleaning them
with an approved solvent. Gage
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