How to Choose Calibration Weights

To ensure that your weighing scales or balance is correctly weighted we suggest you test it with Atlantic Scale scale calibration weights. This could be daily, weekly or on a monthly basis, depending on how important the measurement is for the products or your processes.

You would, most likely, have a weighing company that measures and certifies your weighing instruments on a semi-annual or annual basis. This means, however, that the scales are only correct when they are being certified. If you feel the weighing results are important, we recommend further checks to ensure no calibration error is caused by any damage or failure.

Weight and Mass

Without the control of calibrated weights even a poorly fitted protective cover can cause significant weighing errors.

Weight is the force applied by a mass when gravity acts on it. This is then measured using a weighing balance. However, weight is the more common term, so we use it throughout this guide.

Types of Calibration Weights

A sturdy material with very low magnetism will make a high quality calibration weight. Calibration weight come in numerous shapes, sizes, materials, and precision. We have provided some information for you to use in selecting the most suitable test weight or weight for your unique needs. 

Cast iron bar & hex calibration weights

These calibration weights are used to test factory, commercial and retail scales. They are the most common form of calibration weights. Industries has adopted fabrics because of it light weight, click to learn more on how fabric structure companies fail to take an in-depth look into the mechanics of a fabric covered building using a linear analysis. This means that when the fabric is under pressure from the weight of snow or other environmental elements, the fabric moves in exact proportion to the amount of load applied. If the load doubles, the fabric moves twice as far.

The M1 tolerance/class is the standard to which the weights are usually set. This equates to an accuracy of 1:20,000 or 0.005%. This implies that a 10 kg (10,000g) calibration weight with an M1 accuracy will have a maximum error, when measured, of +/-0.5g. This will be further discussed in the Weight Classes section.

These weights are designed for one person to lift, but remember that it can be hard for some to carry heavier weights.

The bar weights (5 kg, 10 kg, 20 kg and 25 kg) are so called, because of a bar they possess that serves as a handle. Also, the weights are hexagonal from 100 g to 2 kg.

For testing and calibrating all scales at a resolution of 1 g or higher, we suggest our cast iron reference weights. They are stable when used and also cost less than other options if kept in a dry environment.

We suggest brass or stainless steel weights if you need weight for a wet environment because iron weights rust when wet and soon afterwards go out of tolerance.

Brass calibration weights

Cylindrical brass weights of 1 g to 10 kg are available and are provided in accordance with M1 standards (see Iron Calibration Weights for details)

Brass is less wear-resistant than the iron weighs, but more water-resistant because it does not rust, making them a popular choice for measuring weighing scales in food factories and other conditions in which the weights can be brought into contact with the water. Where you have an even bigger budget, you may want to consider using stainless steel weights as they are much more water-resistant and wear-resistant.

For information about these calibration weights, click on this link.   

Stainless steel calibration weights

Stainless steel cylindrical weights are an excellent choice (if your budget permits) for calibration weights.

The only drawback on the other weighs is the fact that larger weights are harder to carry than those of iron bar weights, but on the plus part, they are wear-resistant and most resistant to water, bonds and other contaminants.

The test weights in steel are stable enough for greater accuracy standards than those of iron or brass to be delivered.

Stainless Steel Test Weight CategoryProsConsAccuracy
M1More stable than both iron and brass weightsIdeal for testing scales and portable balances in all environments 10g = +/- 0.002g 100g = +/- 0.005g 1000g = +/- 0.05g
F1Ideal for testing and calibrating precision balancesHas a very smooth finishMore accurate than the F2 class stainless weights.Needs to be handled with care using special gloves to remain accurate10g = +/- 0.2mg 100g = +/- 0.5mg 1000g = +/-0.005g
F2Ideal for testing portable and precision balancesHas a smoother finish and are more accurate than the M1 class stainless weightsNeeds to be handled with care10g = +/- 0.005g 100g = +/- 0.015g 1000g = +/- 0.15g
E2Ideal for testing and calibrating analytical balancesHas a highly polished surface finishThe most accurate weightsNeed to be handled with care using special gloves or tweezers10g = +/- 0.06mg 100g = +/- 0.15mg

Slotted Calibration Weights

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