Stainless Steel Class F Test Weights General Information
Stainless Steel Class F Test Weights are primarily used to test commercial weighing devices by state and local weights and measures officials, device installers and service technicians. Stainless Steel Class F Test Weights may be used to test most accuracy Class III scales, all scales of Class III L or IIII, and scales not marked with a Class designation. Class F is also acceptable for use verifying scales that have 0.1% accuracy or lower. Stainless Steel Class F Cylindrical, Cube and Grip Handle Weights are legal for trade, which means their design meets specifications as outlined in NIST Handbook 105-1 and are approved to be used on legal for trade devices within the United States. Weights 5 kg / 10 lb and below must be made of stainless steel of quality not lower than 300 series stainless steel. Adjusting cavities are typically on the top of the weight and must be tamper resistant
NIST Class F Tolerances
The tolorance applied to a weight have been chosen to be small enough to be negligible when testing a device, be a small franction of the nominal value of the weight, and yet large enough to be practical for manufacturing a weight. These considerations are conflicting so that it is impossible to have the same fractional tolerance over the entire span of nominal values from 500 kg to 1 mg.
Construction and General Shape
Troemners Stainless Steel Test Weights are available in a variety of styles, including cylindrical weights, cube weights, and stackable grip handle weights. Troemners Stainless Steel Test Weights are manufactured from grade 303 stainless steel alloy that possesses closely controlled density, low magnetic susceptibility, good stability and resistance to corrosion and handling damage.
- Weights 200 g, 8 oz, 0.5 lb, or 5 ozt and larger have two-piece construction which indicates that the weight is constructed of multiple pieces of raw material. In the case of Class F weights, this means that the weight body is constructed from one piece of material with an adjusting cavity. This cavity contains the adjusting material, which is typically the same material from which the weight is made. Once the weight is adjusted into tolerance it is sealed using an aluminum cap and stainless steel back-up spacer.
- Cylindrical weights (smaller than 200 g, 8 oz, 0.5 lb or 5 ozt) are one-piece construction, which means the weight is manufactured from a single uniform piece of raw material. One-piece Class F weights of this size are adjusted by grinding material off the bottom of the weight.
- Weights 12 GN through 2 GN and 500 mg through 200 mg and .05 ozt through .005 ozt are flat stainless steel with one side of the weight turned up for easy handling.
- 100 mg through 1 mg weights are flat aluminum with one side of the weight turned up for easy handling.
- A one-piece construction weight has no other material added to it, and it has no method of adjustment other than removing material by grinding or polishing.
The surface finish of a new weight machined from round bar stock shall have a roughness average of 0.80 micrometers (32 microinches) or better, determined by use of a hand held surface roughness indicattor (available from several manufacturers) or more accurate method, and be free of scratches, dents, and chipped corners or edges, determined by visual examination. A beaded or blasted finish (with average 1.25 micrometers (50 microinches) or better) is acceptable on a cube weight to facilitate gripping.
A weight 5 kg/10 lb or less shall not have a surface coating.
- Individual weights are not supplied in protective cases as standard. However, for an extra charge, a polypropylene protective weight case can be specified and ordered in a variety of constructions to meet your needs.
- Weight sets are supplied in sturdy plastic cases with a carrying handle. Larger weight sets where the total weight is greater than 10 kg or 15 lb are supplied in a case with metal reinforced corners and bottoms with padded handles for easier carrying. Weights 200 g / 8 oz and above have their own compartment within the dense foam interior case. Smaller weights are contained within a smaller synthetic leather case that fits into the larger "master" carrying case. This "case within a case" design helps keep smaller weights from getting lost and also allows smaller weights to be taken out of the master case and used closer to the users application.
Ordering a Certificate With Your Weight or Weight Set
The following certificates are available to meet your traceability and compliance needs. Complete information on our calibration certificates and samples of certificates are located in the Mass Calibration and Certificate Options section of the web site.
- Weights and weight sets supplied without weight certificates come with Troemners Statement of Accuracy
- To order Troemners NVLAP Weight Calibration Certificate, specify the Troemner part number followed by "W". For part numbers, please reference the Ordering Tables
- To order Troemners Traceable Certificate, specify the Troemner part number followed by "T". For part numbers, please reference the Ordering Table
Stainless Steel Test Weight Sets Configuration Information
Troemners Stainless Steel Test Weights are available in a variety of standard configurations and set capacities including cylindrical weights and cube sealer weight sets. Review the following configuration tables to determine which set meets your needs. If you do not see a set that meets your needs, a customized weight set consisting of the weights you require can be configured and supplied in a protective weight case.