USE/CARE OF HANDTOOLS & MEASURING TOOLS - OD1621 - LESSON 3/TASK 1
(b) Hook Rule. A hook rule has a sliding hook which facilitates
measuring from a shoulder, particularly if the end of the rule is hidden so
that it cannot be lined up with the shoulder.
The sliding hook is also
convenient in setting calipers and dividers.
(c) Short Rules and Holders.
Short rules with
a
holder
are
available for measuring in a recess or in a restricted area.
(d) Flexible Fillet Rule. A flexible fillet rule is used to span
fillets and corner fills which are frequently in the way when measuring
flanges, shoulders, etc.
(e) Key Seat Clamps.
Key seat clamps (figure 164) are made of
steel, are case hardened, and weigh 1 ounce each.
They are designed to
transform any straight steel rule into a rule that can be used to lay out
keyways on the cylindrical surface of a shaft.
FIGURE 164.
KEY SEAT CLAMP.
(2) Shrink Rule. The shrink rule (figure 165 on the following page)
resembles an ordinary rule, except that its scale automatically compensates
for the shrinkage in castings. In the manufacture of a
216
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