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Professional Weighing Scales and Balances UK
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Calibration Weights for Scales & Balances

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Calibration Weights are used when calibrating weighing scales and balances to ensure consistent weighing performance and accuracy. Choose from our selection calibration test weights and weight sets ranging from 1g to 50kg with stainless steel, cast iron and brass variations available.

The different test weight options available can be confusing and you might well ask what the difference is between an M1 and an F1 weight, or why you might use one rather than the other. We have compiled a brief overview of the calibration weights we offer, and additional information on the importance and how to calibrate a balance with weights within our related articles below:  

M1 Class Test Weights: The most widely used test weight class on the market today. These weights are used to calibrate scales and balances where exact precision is not necessary. All class III scales use these weights for reference and calibration.

F1 Class Test Weights: Common weights used for standard precision balances and scales. These weights have a high degree of accuracy, but more cost effective than the E1 and E2 classes. Mainly used in laboratories, calibration houses and quality control areas.

E2 Class Test Weights: The most precise test weights available. These weights should be used on balances and scales with very fine resolutions, such as micro and analytical balances. Most commonly used in test and calibration houses and within the chemical and pharmaceutical industries.

Guide to Calibration Weights - Free PDF Download

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  1. From: £113.00  (Ex.VAT)

    RRP £120.00 (Excl.VAT)

    Readability Range
    g to g

    OIML weight sets are a complete set of test weights that can meet the requirements for testing to OIML standards. E2 and F1 weights offer the highest accuracy required for analytical and precision balances, M1 weights offer the lowest accuracy but are more affordable and are ideal for compact balances and bench scales.

  2. star 1 selected - rating 5star 2 selected - rating 5star 3 selected - rating 5star 4 selected - rating 5star 5 selected - rating 5 (customer on-site rating)
    From: £10.00  (Ex.VAT)
    Max Capacity Range
    1g to 5000g
    Readability Range
    g to g

    Each OIML weight is an individual stainless steel weight that meet the requirements for testing to OIML standards. E2 weights offer the highest accuracy required for analytical and precision balances, M1 weights offer the lowest accuracy but are more affordable and are ideal for compact balances and bench scales.

  3. From: £47.00  (Ex.VAT)
    Readability Range
    g to g

    Cast iron weights are available in OIML M1 class, they offer higher capacities to meet the needs to calibrate larger scales such as industrial platform and floor scales.

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Calibration Weights Help

How to choose calibration weights

A: There are many different types of calibration weights that are used for different applications and this is not easy to answer briefly, but a good basic guide will follow this rough principle: Scales that have a coarser resolution of 0.1g, 1g and above should use M1 Class weights, 0.01g to 0.001g use F1 Class weights, whilst E2 and E1 weights should be used to calibrate balances that have a finer resolution than 0.0001g.

How to clean calibration weights

A: Weights should be dusted routinely before use, using a clean, soft-haired brush but they should not be more extensively cleaned unless it is absolutely necessary. More extensive cleaning may adjust the weight, so before cleaning measure the weight and again after cleaning to ensure it has not gone out of tolerance.

When handling calibration weights, you should always use protective gloves and fine tweezers to pick up the weights and place them onto a weighing scale pan. Picking up weights, particularly of fine-resolutions, without gloves can lead to a build up of material on the weight which will in turn affect the weight's tolerance.

How to store calibration weights

A: Calibration weights should be handled with care. They should be stored in individual boxes, wooden or plastic to protect them from dust and atmospheric pollution, and should also be stored in a suitable cupboard. Sets of weights used regularly should be stored in a suitable sized wooden or plastic box with individual compartments for each weight. Weights should not be stored on shelves or racks without adequate protection from the environment.

Is it possible for internally calibrated weighing scales to be calibrated externally as well?

A: In general yes they can - Most scales and balances with internal masses use a smaller reference weight, and can be calibrated to their full capacity using external masses.

How often should you calibrate scales and balances?

A: Most specialists would agree that scales and balances should be calibrated on a regular basis. Regular calibration is essential to the overall performance of your weighing instrument and is mandatory for businesses that conduct transactions based on weight.

Scales should be calibrated on a weekly or monthly basis, however, for more specialist requirements and instruments, such as semi-micro balances and analytical balances, we would recommend conducting daily calibration tests in order to maintain optimum results.

Related Articles:

What OIML stands for and why it is important.

Just How Important is Calibration?

Internal and External Calibration: Which is right for you?

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