d. Although the information presented is used on tolerances, denominations
and materials, weights in all classes must meet the following NBS requirements:
Design - general shape, thickness, number of pieces.
Surface - irregularities, porosity.
Denominations - systems of units, numerical series.
Tolerances - acceptance, maintenance.
Marking - identification.
Handling - lifters.
We don't include all of the classes into which weights are
The classes identified are included so that you realize differences
between weights used in your laboratory.
The list which follows compares
acceptance and maintenance tolerances for some of the different classes of weights.
Classes of Weights
f. 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.