USE/CARE OF HANDTOOLS & MEASURING TOOLS - OD1621 - LESSON 3/TASK 1
(3) Folding Rules. Folding rules (figure 166) are obtainable in wood
or metal, having 4 to 12 folds, from 2 to 6 feet in total length.
See
figure 166 for examples of variation in folding rules. These rules cannot
be relied on for extremely accurate measurements because a certain amount of
play develops at the joints after they have been used for a time.
FIGURE 166.
TYPES OF FOLDING RULES.
(4) Circumference Rule.
The circumference rule (not illustrated)
supplied by the Army Ordnance Supply System is 36 inches long, 1 1/4 inches
wide, 1/16 inch thick. Both sides are marked with graduations of 1/16 inch
on one edge and 1/8 inch on the opposite edge.
This rule is capable of
measuring a 36 inch diameter and 113 inches maximum circumference reading,
using a conversion scale.
(5) Glazier's Rule.
A glazier's rule (figure 167 on the following
page) is used primarily for measuring glass and has a lip, similar to a hook
rule. The lip is non-adjustable and is used as a
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