PRECISION MEASURING AND GAGING - OD1642 - LESSON 1/TASK 2
(c) Care. Although sine bars have the appearance of being rugged,
they should receive the same care as gage blocks. Because of the nature of
their use in relation with other tools or parts that are heavy, they are
subject to rough usage.
Scratches, nicks, and burrs should be removed or
repaired.
They should be kept clean of abrasive dirt, sweat, and other
corrosive agents.
Regular inspection of the sine bar will locate such
defects before they are able to affect the accuracy.
When sine bars are
stored for extended periods, all bare metal surfaces should be cleaned and
then covered with a light film of oil. Placing a cover over the sine bar
will further prevent accidental damage and discourage corrosion.
(10) Parallel (Bars) Blocks.
Parallel blocks (figure 26 on the
following page) are hardened, ground steel bars that are used in laying out
work or setting up work for machining. The surfaces of the parallel blocks
are all either parallel or perpendicular, as appropriate, and can be used to
position work in a variety of setups with accuracy. They generally come in
matched pairs and standard fractional dimensions.
Care should be used in
storing and handling them to prevent damage.
If it becomes necessary to
regrind the parallel blocks, be sure to change the size that is stamped on
the ends of the blocks.
FIGURE 26.
PARALLEL BLOCKS.
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