ASTM E Tolerances have been converted from avoirdupois to metric and rounded to two significant figures. Nominal Size. Class 0. Class 1. Class 2. services. The weight portfolio covers both OIML and ASTM weights from ASTM weights are available in classes 1 – 6 matching requirements of ASTM E International Organization of. Legal Metrology Recommendation R Troemner UltraClass Series. ANSI/ASTM E NIST Handbooks**. Weight. Class. E0*.
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United States Download From http: The awtm of weights smaller than 1 mg shall be discussed and verified with the customer. The back-up spacer should be of a similar material as the weight. They should be used in extremely stable environments and handled with the highest level of care. From the context it is usually clear in which sense the term is used. Both sheet metal and wire weights shall be free of cracks such as may be formed from bending.
This is an upper limit for the uncertainty.
The nominal value of each weight is etched or stamped on the top surface of the weight and their shape is square. Troemner weight sets, where the largest weight is g adtm larger are supplied in handcrafted wood cases. Adjusting material and back-up disc must meet the magnetic requirements specified for the accuracy class of the weight.
The acceptable maximum values for user markings are given in Table 7. Troemner UltraClass weights combine high precision with the advantage of two-piece construction 1g and larger e61 costly replacement issues associated with one-piece weights. We need your help! The Sheet Metal Weights come standard with the weight products. In the case of sets of asm weights, at least the largest weight of a particular set should be marked with the unit name or abbreviation.
One-piece weights are difficult to manufacture as the only method of final adjustment is removing material by polishing. Class 1 weights can also be used to calibrate Class 2 weights.
When calibrating class00 and 0 weights, it is recommended to perform several test measurements at different times to ensure that there is enough information about the uncertainty at the time of the measurement. Historical Version s – view previous versions of standard Work Item s – proposed revisions of this standard Translated Version s: If magnetic effects are negligible, i.
National prototype standard—platinum-iridium kilogram identified as K20, maintained at the National Institute of Standards and Technology, with value assigned relative to the International Prototype Kilogram provides the United States access to the mass unit.
Weight bottoms are slightly recessed to expose the smallest possible area to wear. As lower precision of measurement is required, so the range of density is broadened.
Class 0 weights 1 g and larger are of one-piece construction using Troemner Alloy 8 Stainless Steel, which has a consistent density. For weights larger than g, a velvet lined compartment for each weight exists within the wood case. A larger uncertainty cannot be arbitrarily chosen. Troemner UltraClass weights can also be used to calibrate Class 1 weights. NOTE 2—Maximum Permissible Errors for weights of denomination intermediate between those listed, the maximum permissible error shall be proportional to the values shown.
If the sensitivity is not constant with time, temperature and load, its variation must be included in the uncertainty. The weights are manufactured of the finest stainless steels available including Troemner Alloy 8 Stainless Steel, which was developed by Troemner and is available exclusively through Troemner. The magnetization of a body generates an inhomogeneous magnetic field in space and thus may produce magnetic forces on other materials.
Cast iron cannot have a susceptibility specification of any real value. This uncertainty contribution is applicable, if it is known from previous interchanging measurements with weights of the same nominal value.
This will lead to linear summation of uncertainties: Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Please see the Tolerance Chart within the Mass Standards Handbook for the specific tolerances of each weight in any given class.
The surface requirements shall be met at the end of the adjustment process. There are no markings indicating nominal value on any Class 0 weights. It is the finest grade of stainless steel available and is similar to material originally specified in the manufacture of state primary standards.
They can also be used to calibrate Class 3 weights. The outer diameter, top and bottom surface roughness must meet Table 6. The letter R is indicative of the type of assessed profile, in this case R for roughness profile.
Troemner supplies appropriate lifting devices such as forceps, gloves, and other lifting forks sufficient to handle every weight in the set. Weights made of wire or too small to be marked shall not be marked but should be identifiable by their shape or number of bends.
ASTM E – 97() Standard Specification for Laboratory Weights And Precision Mass Standards
Periods shall not be used with abbreviations in marking weights. Ordering Information 4 and 5 6 and 7 80 Not applicable 6. There is also a compartment for forceps.