f. Working Standards (STS).
(1) Q - general laboratory, technical, and student weights (for use with precision
pressure gages and for technical work of commercial and student laboratories).
(2) C - general laboratory technical and student weights (used as a working
standard for sealers of weight measures).
(3) T - utility weights (used for rough weighting such as force and torque
measuring apparatus). They are used by Army TMDE Support teams (ATST) to
calibrate scales, weighing devices, torque calibrators, and other devices which
permit their tolerance and characteristics.
(4) The class C, Q, and T weights are calibrated by Army Area Calibration
Laboratories (AACL) using weights having a higher degree of accuracy. The
weights which we have discussed so far all require calibration. We should bear in
mind that in order to be classified as a certain type or class, a weight must meet
certain requirements or specifications of that class.
g. Commercial.
(1) A - primary state standards.
(2) B - state working standards.
(3) C - test weights (for certification of commercial weighing equipment).
h. From the preceding list of comparisons, you should conclude that a single class of
weights has an acceptance tolerance which each weight must meet when manufactured
and a maintenance tolerance which each weight must meet while it is in use. As indicated
in the preceding list of comparisons, weights of different sizes within a given class may
or may not be the same.
i. Characteristics. Some classes of weights have provisions for adding or removing small
amounts of weight for adjustment purposes. Class S and S-1 weights have removable
knobs which cover a small chamber within the weight. Small filings or shot added to or
removed from the chamber are used to trim the weights to maintain tolerances such as
those in the preceding list. Weights of one class generally are supplied in sets such as
those shown in figure 2. Weight sets are delivered in various denomination sequences;
however, the most common acceptable sequences are: 5-3-2-1, 5-2-2-1, or 8-4-2-1. The
sequences listed are in the descending order. In some instances you may see them
identified in the ascending order.
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