There are several shapes, designs and sizes available to meet your needs. Selecting the proper weight can be confusing given the number of weight classes, designs, and materials available.
The following issues need to be considered when selecting weights:
Application Accuracy The correct weight for an application should be more accurate than the precision of the weighing device, and must be more accurate than the required precision of your measurement result. It is recommended that a weight have an accuracy that is 1/3 of the measurement device readability and/or your measurement accuracy requirement.
Environment Temperature and humidity can impact the stability of weights. We recommend stainless steel weights for applications in environments that have excess moisture, changes in temperature or humidity, or are in corrosive environments. Stainless steel is much less prone to physical change as compared to cast iron.
Cleanliness of the environment can impact how stable your weights will be over time. Environments with excessive airborne matter, such as dust, can impact the stability of weights. The smoother the surface of a weight, the easier it is to see foreign matter so it can be removed.
Reported Uncertainty on Calibration The uncertainty reported on a calibration is just as important as the measured value itself. The uncertainty provides the statistical confidence that a laboratory has for its calibration process. The larger the uncertainty, the less confidence in the measured value. It is also important to realize that a measured value added to its associated uncertainty must be less than the tolerance for the weight to be considered within class tolerance.
Specific Design or Construction Troemner manufactures a variety of special application weights, such as weights with hooks or weights that can be stacked on a hanger in order to build up to the total weight. Keep in mind that if you do not see what you need on this site, please contact a Troemner Sales Representative at +1-800-352-7705.
Troemner offers the most comprehensive selection of precision weights and mass standards. Our weight selection includes every imaginable size, class, and type from 10,000 kg stainless steel weights to the extremely precise, highly polished one and two-piece stainless steel weights.
At Troemner, careful attention is paid to every detail of production. Weight bottoms are slightly recessed to expose the smallest possible area to wear. Weight heads and necks are precisely shaped to give a solid, sure grip to forceps or weight lifters. Troemner uses the finest materials available for the production of all of our weights and mass standards.
For your most demanding applications, our precision weights are manufactured from Troemner Alloy 8, which is a specially developed stainless steel. Troemner Alloy 8 possesses closely controlled density (8.03 g/cm3), extremely low magnetic properties, excellent stability, and very high resistance to corrosion. We manufacture and calibrate weights to meet or exceed the highest tolerance standards of ANSI/ASTM, OIML and NIST.
ANSI/ASTM E617 Standard Specification for Laboratory Weights and Precision Mass Standards
This specification covers various classes of weights and mass standards used in laboratories ranging from Class 000 to Class 7. Tolerances and design restrictions for each class are described in order for the appropriate applications. This specification also recognizes OIMl R 111 that describes class E1, E2, F1, F2, M1, M2 and M3.
OIML R 111 Weights of Class E1, E2, F1, F2, M1, M2, M3
This international document describes the physical characteristics and metrological requirements of weights that are used for the verification of weights of a lower class of accuracy and with weighing instruments. This document includes a recommendation for seven classes of weights in tiers of uncertainty.
NIST Handbook 105-1 Specifications and Tolerances for Field Standard Weights
These specifications and tolerances are specific for reference and field standard weights (NIST Class F). Reference and field standard weights are used to test weighing devices where the weight of the item is required to determine the item's price. This document sets minimum requirements for standards used primarily to test commercial or legal for trade weighing devices for compliance with NIST Handbook 44. These devices include, but are not limited to, delicatessen scales, jewelry scales, postal and parcel post scales, and dairy product scales. This specification permits the use of a weight at its nominal value in normal testing operation, where the tolerance of the item under test is at least three times as great as the tolerance of the weight. This handbook also specifies the design, marking, adjusting cavities, and density of these weights. Any variation in design from Handbook 105-1 must be submitted to NIST for approval.