The Measurement Shop's Guide to Hardness Meters

Hardness testing is a process that spans many industries and essentially allows you to assess the properties of a given material. These properties could include strength, resilience, flexibility and many others that are crucial to so many manufacturing and engineering procedures. To do this, a device known as a hardness meter, or hardness tester, would be used.

This hardness tester guide will aim to give you all the information you need when purchasing your hardness meter with The Measurement Shop. It will cover what they are and what they are used for, as well as which hardness testing methods are available and what the benefits of each are. Click here to view our hardness conversion chart to make switching between units fast and simple.

What is hardness testing?

As you might expect, a hardness meter is a device that determines the hardness of a material. This does not work in same manner as measuring say height or weight, because there isn’t actually a specific quantitative measurement for hardness. It is not a principal characteristic of a material. Instead, you are measuring a materials ability to tolerate deformation from the device that you are using.

As explained previously, these tests give a clear indication about the properties of the material. This could be plastic, metal, rubber, or any material that can be found in an engineering, industrial or manufacturing environment. You would find these devices across many different industries, including architecture, aeronautics and automotive to name just a few. Generally, hardness meters are used to either quality check a material to ensure it is in line with specifications, or to determine the unique characteristics of a new material.

Hardness tester types

There is more than one hardness tester machine available and each comes with their own uses and units of measurement. The main ones are:

Portable hardness testers:

Leeb: Leeb hardness meters, also known as Scleroscopes, are devices that use the rebound method to measure material hardness. They are popular because of their portability and simplicity. A hollow tube stands upright on the material and a ball hammer is dropped. The velocity of the hammer is measured by an electronic sensor both when it goes towards and away from the material. The equation for the Leeb method is:

HL=(Rebound Velocity)/(Impact Velocity)*1000

UCI: The UCI hardness tester (Ultrasonic Contact Impedance) is a fast and portable hardness testing device that causes minimal damage to the subject. This device is positioned by hand and utilizes a motorised measurement probe that takes only seconds to process and display results. The force does not come from the users hand, but instead from the motor within the device.

Static hardness testers:

For static appliances that would be found in testing facilities, there are considered to be 3 main types. Please note that The Measurement Shop does not stock any of the following hardness testers:

Vickers: One of the most popular hardness tests, the Vickers method uses a square based pyramid indenter made from diamond. This method is especially good for softer materials and produces highly accurate results. The indenter makes a dent in the material using a relevant value of force for a specified amount of time, and then the measurement can be observed. The equation for the Vickers test is:

HV=0.1891 F/d^2

F=Force d=Indentation diagonal (mm)

Brinell: The Brinell hardness test is a method that uses a ball with a diameter of 10mm to create an indentation into a given material. The indentation is created by applying a constant force of up to 3000kg (depending on the material) for a given time. Once the indenter has been removed, the depth of the dent is observed using low powered microscopes that will take the average of the measurements at right angles. The equation for the Brinell test is:

HB=2F/(πD(D-√(D^2-d^2 )))

F=Force D=Indenter Diameter d=Indentation diameter

Rockwell: The Rockwell hardness test works in the same way as both Vickers and Brinell – force is exerted on an indenter which makes a measurable imprint on a given material. For this method, the depth of the imprint is measured. Uniquely, a minor load is applied before the test which aims to break the surface of the material only slightly. This is done to prevent any flaws in the surface from affecting results, thus making it a more accurate method. The Rockwell approach also uses 30 individual scales, meaning it is capable of testing a wide range of materials with very different properties. The Rockwell equation is:

HR=N-h/s

H=Factor dependent on scale used h=Depth of indentation mm (from minor load) s=Factor dependent on scale used

Measuring plastic hardness:

If you want to use a hardness tester for plastic, you have 2 main options: Rockwell (see above) or Shore.

Shore: These devices are often referred to as durometers and are used to test soft and hard plastics. For the softest materials Shore 0 is used, whereas medium plastics such as rubber, vinyl and polyolefin, Shore A testing is used. Shore D is preferred when measuring hard rubbers, semi-hard plastics and hard plastics. They work in a similar way to most other hardness meters in the way that a force is applied to a material via an indenter. However, the imprint is not measured and instead the results are directly related to the force applied for the probe to penetrate the material.

Which hardness tester is right for me?

Choosing a hardness meter can be overwhelming at first because of so many options. Let’s look at some key factors to consider before you buy:

• Material Type: The material type will potentially be the main factor to consider. This will determine the test load of your device, as well as the hardness range and material of your indenter. Steel and diamond are the main indenter materials, although other metals can be used.
• Portability: Decide whether you need a static instrument or something you can take with you on the go.
• Method: As explained previously, there are many different types of testing methods available for hardness testers. Vickers, Brinell, Rockwell, Leeb, UCI and Shore are made for different materials, hardness levels and environments – so be sure to know what you need.

Our hardness meters

Here at The Measurement Shop, we stock a range of UCI, Shore and Leeb Hardness Meters in a range of affordability options. Here are some of our most popular. To see the full list of products please visit our full hardness tester page

HO Sauter Mobile Ultrasound Hardness Tester

For instant results, the HO Sauter ICU portable metal hardness tester is perfect. This ultrasound testing device is ideal for measuring welding points, punched parts, casting tools or small forgings, as well as much more. It is one of the most portable devices available and causes far less damage to the subject than Rockwell or Brinell testing methods.

HB Sauter Mechanical Shore Hardness Durometer

For a more affordable hardness tester for plastic, the HB Sauter Mechanical Durometer is perhaps the strongest contender. This is a simple device that is accurate and reliable, but above all easy to use. For different materials, Shore 0, Shore A and Shore D are available. For increased accuracy, we would highly recommend using this with the TI Sauter Manuel Hardness Test Stand.

HK-D Sauter Leeb Hardness Meter

This High quality Leeb hardness meter comes with a robust metal housing and offers high levels of flexibility and portability. It comes with a Type D external sensor for measuring all metal samples. The internal memory allows for up to 600 data groups, each with a possible 32 values per group. Despite being a Leeb harness meter, this product can display results in Rockwell (Type A, B & C), Vickers (HV), Shore (HS) and Brinell (HB).

HMO Sauter Leeb Hardness Meter

The HMO Sauter is another Leeb hardness meter, although it comes complete with an innovative touchscreen for making testing easier. Again, this product offers a high level of portability options when compared to stationary devices.

Hardness Conversion Chart

This table contains the approximate conversions of Rockwell A - D, Brinell, Vickers and Scleroscope.