QuickLINKS:
> General Information
> OIML R 111 Class Tolerances
> Construction and General Shape
> Surface Finish
> Suggested Applications
> Presentation
> Weight Set Configuration Information
> Ordering a Certificate With Your Weight
or Weight Set
> Ordering Tables
> Accessories

 
General Information

Troemner OIML Precision Weights conform to the standards of the Organisation Internationale de Metrologie Legale International Recommendation (OIML R 111). They are manufactured from the finest stainless steels available including Troemner Alloy 8 Stainless Steel that has low magnetic permeability, uniform consistency and high resistance to corrosion. Troemner OIML Precision Weights are available in Classes E1, E2, F1 and F2, where Class E1 has the smallest tolerances and Class F2 has the largest tolerances. The letter "E" for Classes E1 and E2 refers to "extra fine" where the letter "F" for Classes F1 and F2 refers to "fine". OIML R 111 weight specifications are designed so the specifications on surface finish, markings, construction, material density and magnetic properties get more restrictive as the weight tolerances get smaller in order to enable the weight to maintain its tolerance over time. The tolerances for the various classes are established in a manner that enables weights of higher classes to calibrate weights of the next lowest class. For example, Class E2 weights can be used to calibrate Class F1 weights. Troemner OIML Precision Weights and Weight Sets are supplied with Troemner's Statement of Accuracy, which details the date of calibration and accuracy class of each weight. If your laboratory requires more stringent documentation, please review the Weight Calibration and Certificate Options section of the website.

**Caution** Class E1 weights have extremely small tolerances and are intended to be used as primary reference standards with direct traceability to national reference standards. They should be used in extremely stable environments and handled with the highest level of care. Otherwise, Class E1 weights will not maintain their measured value within the tolerance class. One may be tempted to purchase the weights with the tightest tolerances in order to reduce measurement uncertainty. However, frequency of use, care, handling, and environmental conditions all play a major role in long term stability of weights and these factors should be considered before purchasing Class E1 weights.

 
OIML R 111 Class Tolerances

Please see the Tolerance Chart within the Mass Standards Handbook for specific information on the tolerances of each weight of a given OIML Class.

 
Construction and General Shape

• Troemner OIML Precision Weights 500 mg and below are made of sheet metal and are one-piece construction with one side turned up to make them easy to handle with forceps. Corners and edges are smooth. There are no markings permitted on any sheet metal weight 500 mg and below. The nominal value of weights 500 mg and below are determined by the shape of the weight according to the table below.

  

   
  
• Weights 500 mg and below are also available in wire construction as opposed to sheet metal with the same shape configuration as listed in the above table. Troemner's OIML wire weights have one end turned up as well to allow for easy handling with forceps. Contact a Troemner sales representative for more information on wire milligram weights. To order wire milligram weights, specify the Troemner part number listed in the Ordering Tables below followed by "-WIRE".
   
  
• Weights 1 g and above can be either one or two-piece construction. Troemner OIML Precision Weights 1 g and larger are cylindrical in shape with a tapered neck for easy gripping. They are perfectly flat on top to stack easily on center. Weight bottoms are slightly recessed to expose the smallest possible area to wear.
   
  
• One-piece construction indicates the weight is manufactured from a single uniform piece of raw material, the weight has no other material added to it, and it has no method of adjustment other than removing material by grinding or polishing. One-piece weights are difficult to manufacture as the only method of final adjustment is removing material by fine grinding, polishing or electro-polishing. Class E1 and E2 weights 1 g and larger are cylindrical in shape and are of one-piece construction.
   
  
• Two-piece construction indicates that the weight is constructed of multiple pieces of raw material. In the case of Troemner OIML Precision Weights, this means that the weight body is constructed from one piece of material and the lifting knob or head is constructed from a different piece of raw material. Although the head and body may come from different bars of raw material, they are the same grade and type of raw material with the same densities. The knob or head typically screws into the body and one can barely tell the weight is not constructed of one piece of material. There is a cavity below the knob thread in the body, which contains adjusting material that is typically the same material from which the weight is made. Class F1 and F2 weights 1 g and larger are cylindrical in shape and are of two-piece construction.
   
  
• Click here to view a table that describes the material used in the construction of all of Troemner's OIML Precision Weights.

 
Surface Finish

All surfaces are polished to a perfect, mirror like finish and meet or exceed OIML R 111 specifications. For OIML R 111 Surface Finish specifications see the Mass Standards Handbook.

 
Suggested Applications

• Class E1 weights are intended for use in metrology laboratories as primary reference standards where the stability of the environment and careful handling are assured. Although very stable, one-piece construction Class E1 weights have no method of adjustment and are not suitable for general laboratory use.
   
  
• Class E2 weights can be also be used as reference standards as well as calibrating Class I balances as specified in OIML R 76. Class E2 weights can also be used to calibrate Class F1 weights.
   
  
• Class F1 weights can be used to calibrate certain Class I balances and scales as specified in OIML R 76. Class F1 weights can also be used to calibrate Class F2 weights.
   
  
• Class F2 weights can be used to calibrate weighing instruments for important commercial transactions like gold and precious stones. They can also be used to calibrate Class M2 weights.

 
Presentation

• Weight sets where the largest weight in the set is 200 g and lower are supplied in attractive, durable polypropylene cases with a compartment for each weight within the case. There is also a compartment for forceps. The cases are designed so that each weight will stay in its compartment. A wood case may be substituted for the polypropylene case for an extra charge.
   
  
• Troemner weight sets 500 g and larger are supplied in wood cases. Within the interior of the wood case is contained a polypropylene case to hold weights 200 g and below with compartments for each weight. For weights larger than 200 g, a velvet lined compartment for each weight exists within the wood case. There are also compartments for lifters and forceps supplied with each weight set.
   
  
• Troemner supplies appropriate lifting devices such as forceps, gloves and other lifting forks sufficient to handle every weight in the set.
   
  
• Individual weights are supplied in polypropylene cases. For weights larger than 5 kg, weight cases have reinforced corners.
   
  
• Wood cases for individual weights are available for an extra charge. The wood cases feature a fine wood exterior with an interior compartment that is either fully lined with padded velvet or velour for the weight or the case has a foam interior.

**Caution** Weight cases are not intended to be used as shipping containers. When you ship your weights to be calibrated, the weights and weight sets must be overpacked in larger containers and/or cartons to protect your weight cases.

 
Weight Set Configuration Information

Troemner OIML Weight Sets are supplied in a 5-2-2-1 series. 5-2-2-1 series means that weights beginning with a "2" are doubled in each decade and weights beginning with a "5" and "1" are single in each decade. For example, for a set with 5-2-2-1 series from 50 g to 1 g, there is one 50 g, two 20 g, one 10 g, one 5 g, two 2 g, and one 1 g. The OIML Weight Sets Configuration Table that follows shows the contents of each set.

OIML Weight Sets Configuration Table

 
Ordering a Certificate With Your Weight or Weight Set

• Weights and Weight Sets supplied without weight certificates come with Troemner's Statement of Accuracy (view sample of certificate).
   
  
• To order Troemner's NVLAP Weight Calibration Certificate (view sample of certificate), specify the Troemner part followed by "W". For part numbers, please reference the Ordering Tables below.
   
  
• To order Troemner's UKAS Certificate of Calibration (view sample of certificate), specify the Troemner part number followed by "NA". For part numbers, please reference the Ordering Tables below.
   
  
• To order Troemner's Traceable Certificate (view sample of certificate), specify the Troemner part number followed by "T". For part numbers, please reference the Ordering Tables below.
   
  
• To order Troemner's Mass Code Report of Mass Values (please contact Troemner for more information), specify the Troemner part number followed by "M". For part numbers, please reference the Ordering Tables below.
   
  
• To order Troemner's NVLAP Density Determination Calibration Certificate (view sample of certificate) (view sample of certificate) for one-piece construction Weights and Mass Standards, specify the Troemner part number of the weight or weight set and also include part number WDC-1111. For part numbers, please reference the Ordering Tables below.
   
  
• To order Troemner's NVLAP Magnetic Susceptibility Determination Calibration Certificate (view sample of certificate) for one-piece construction Weights and Mass Standards, specify the Troemner part number of the weight or weight set and also include part number MAGCAL-1111. For part numbers, please reference the Ordering Tables below.

 
Ordering Tables
OIML Individual Weights
OIML Weight Sets

 
Accessories

Troemner can provide you with all the accessories you need to properly handle and protect your OIML Precision Weights and Weight Sets. Please contact us for specific information on new cases, replacement cases, or special cases you need to store and protect your OIML Precision Weights and Weight Sets.

OIML Weight Accessories