Category: Ames How To

The Importance of Hardness Testing in Machine Shops, Freight Yards, Warehouses, Factories and Laboratories

Hardness testing of metals before and after heat-treating is a common practice in manufacturing establishments like yours. Tests are made of materials before machining begins; of tools that are used and to check hardness after heat-treating.

Sheets of metals are tested to make certain they are not too hard to cause breakage of valuable dies. Bars are tested to insure proper machining speeds and protection of turning tools. Heat-treated parts are checked to control hardness within established limits for better performance and longer wear.

Ames Portable Hardness Testers are ideal for these purposes since they can be taken to the material receiving departments, to machines where you are working, and to every place by inspectors during the entire manufacturing process. Being portable, they check the hardness of parts while in machines being fabricated, and also after being assembled into complete sets.

Ames testers are used to check parts being machined that work harden under certain conditions. You test the hardness of large shear blades and cutters in machines, to check if heat developed in the operation of machines has affected the hardened shafts and parts. A book could be written on the many applications that Ames testers have found.

Customers all over the world learned to expect the best in design workmanship and accuracy in Ames hardness testers. With great pride, Ames offers portable hardness testers to all who make tests in Rockwell hardness scales. They are precisely made, carefully tested for accuracy, and beautifully finished. Enthusiastic owners, like you, have told others about Ames portable hardness testers and the savings made on a variety of interesting applications.

Until Ames Portable Hardness Testers were made in the year 1947, it was thought that only large bench-type hardness testers with weights and levers would give accurate results. Many attempts at building portable hardness testers were made by others that were failures, and the large bench machines seemed like the only accurate dependable type.

Ames employed the principle of the ordinary micrometer a C frame with a screw to perfect a lightweight, accurate easy-to-use hardness tester. Incorporating a sensitive dial indicator and graduated barrel dial, readings are taken directly in the Rockwell scales with no calculating or transposing. No skill is required by the operator, and the tests are made quickly and easily.

Ames portable hardness testers are used everywhere in a plant saving your company installation expenses, cost of transporting materials, and valuable stock that would be cut from bars and or sheets for test purposes with bench testers. Ames portable testers save you the cost of large stationary testers that would otherwise be needed in a plant. The cost of Ames testers is only a fraction of the bench-type testers.

The principle of Rockwell Hardness Testing is based on the scientifically established theory that a definite relationship exists between the hardness of a material and the depth of the penetration when the indentation method of measurement is used. The numbers of the Rockwell scales represent the depth of penetration when standard indenters are used under known pressure loads.

Frequently Used Rockwell Scales

This method has proved practical and accurate and is the simplest and quickest method yet devised for measuring hardness, hence the universal acceptance of Rockwell scales as a standard for measuring hardness. For testing hardened steels and alloys by the Rockwell method, a standard “C” penetrator is used under a pressure load of 150 kgs. The penetrator has a 120-degree cone carefully ground and polished and a diamond point that has been mechanically lapped to a spherical point with a .008-inch radius. For testing soft steels, nonferrous alloys, and cast iron, a standard 1/16″ diameter specially hardened steel ball penetrator, known as the “B” penetrator, is used and a pressure load of 100 kgs is applied. Readings in other Rockwell scales are obtained by using the diamond penetrator and ball penetrators of 1/8″ and 1/2″ diameter and 60 and 100 kg loads.

In the Rockwell method of Hardness testing, two loads, a minor, or initial load and a major load are applied. The depth of penetration actually measured is the additional depth resulting from the major load after the initial or minor load has been applied. This causes no serious difficulty or computation as the tester is set back to zero following the initial load. The resultant reading is believed to be a truer and more accurate measurement of hardness, in as much as surface imperfections or variations in the piece would cause inaccurate readings. By measuring only the increment or additional depth caused by the major load, inaccurate readings due to surface variations are eliminated.

In the Rockwell B and C scales, the minor load is 10 kgs and the major load is 100 and 150 kgs respectively. In the Rockwell Superficial scales, the minor load is 3 kgs and the major load is 15, 30, and 45 kgs respectively. Ames hardness testers employ the same penetrators and pressure loads as specified in Rockwell hardness testing and consequently read directly in the Rockwell scales. A chart of Rockwell scales is provided with each tester giving the penetrators and pressure loads to be used. This chart also gives equivalent Brinell readings.

Using your Ames Rockwell – Brinell Conversion table

Please note the contact information in these charts is not up to date

Ames Portable Hardness testers read in the Rockwell scale. The Rockwell scale uses indentation and measures the depth of that indentation with a major and minor load to determine the hardness of a metal. The scale used depends of the metal being tested and the portable hardness tester used.

Ames developed a conversion chart for use in converting Rockwell scale readings into the Brinell scale. This allows you to easily determine the equal Brinnell reading. This conversion chart is broken down into categories to help you determine the converted value.

Hardened Steel and Hard Alloys, locate the type of penetrator you used and the scale you used in the top column for the scale. In this case you will only see C, A, D, 15N, 30N and 45N scales which can then be converted into the Brinell scale. Follow the appropriate line across to locate the corresponding reading in the middle column marked ‘Brinell’.

The next section is Soft Steel, non-ferrous metal, grey and malleable iron casting, this section covers the B, E, F, G, 15T, 30T and 45T scales. You will need to find the appropriate load in order to find the correct conversion. The bottom of this conversion chart includes corrections which cover any readings that were not included in the original chart.

The right-hand side of the chart gives you a guide to choosing the appropriate penetrator and hardness scale for your metal.

6 Easy Steps to Testing Clutches with your Ames Portable Hardness Tester

Your Ames Portable Hardness Tester was designed for checking the hardness of materials in the Rockwell scales. This has become an asset to the racing industry which has developed a scale* for checking clutches using the Ames Portable Hardness Tester. The Ames tester helps to win races by providing repeatable results every time.

Featured in one of our promotions, Mike Bell, team II driver for Roy Hill Drag Racing, knows how important clutch plate survival is to victory in Pro Stock. Sudden heating can affect both surface and internal structure of clutch metals. Mike used Ames Rockwell Hardness Tester model 2 to check surface hardness of both plates before installation. He used the following recommended configuration. Roy Hill Drag Racing’s Ford Thunderbird set a Pro Stock National record of 6.73 seconds in 1995.

They provide the following recommendations for testing clutches* with your hardness tester in 6 easy steps:

To get yourself set up, make sure you have the following items: Model 2 Ames Portable Tester with a 1-inch anvil and 1/2 inch ball penetrator.

Step 1: Rotate the outer ring on the dial indicator and align the “dot” directly under the indicator needle. Position the clutch between the 1/2 inch ball penetrator and the 1-inch anvil. Make sure the surface is flat and the ball will not fall into holes or grooves.

Step 2: Rotate the handwheel clockwise until the needle on the gauge moves to the set position on the gauge face.

Step 3: Rotate the aluminum barrel counterclockwise so that the pin rests on top of the lucite magnifier

Step 4: Rotate the handwheel clockwise until the indicator needle reaches 60 on the indicator face.

Step 5: Immediately rotate the handwheel counterclockwise until the indicator is back at the set position.

Step 6: Read the black scale on the barrel. The thick line across the barrel is the whole number. (10, 20, 30, 40 etc.) The smaller hash marks on the left side of the barrel are in two-point increments.

Note: It has been established that using this method, test readings that fall between 65 to 80 give the best results.

You probably recognize former racing customers such as Massey Race Cars, Wayne County Speed, Stouts, Carl Smith, Glidden Racing, Ricky Smith Racing, Paul Rebeschi, Gary Brown Racing, Heck Racing, and Nickens Bros. Racing maintenance crews have come to rely on the results provided by Ames hardness testers.



*Please note that this is a special testing method designed by professionals in the racing industry for use as described in these steps and does not represent recommended testing methods for our Ames Portable Hardness Testers.  In this case, the ball penetrator is used and the “B” scale is read.  The ball penetrator is not used to produce readings in the “B” scale.

Rockwell Hardness Charts for Metals

Ames Rockwell-Brinnell Conversion Chart

Our handy conversion chart helps you convert your Ames Hardness Readings from the Rockwell scales to Brinnell scales

Download Now

Choosing a Rockwell Hardness Scale

Below are a few charts that will help you choose the proper set up for your Ames Rockwell portable hardness tester. The charts cover the following :

All information included in this article is found in the Ames Tester Manual. Download it here.

Material to be tested – 

Very hard metals, soft and hard steel, aluminum, brass, and thinner materials can all be tested with our testers.

Brass and aluminum alloys can be handled by using a 1/16 ball

The penetrator that is needed – 

Very hard metals like tungsten carbide, and thin steel needs to be tested using a Diamond penetrator.

Brass and aluminum alloys can be handled by using a 1/16 ball

Brass and aluminum alloys can be handled by using a 1/16 ball

The major load to be applied – 

Your tester is guaranteed to +/- 1 point Rockwell. When using this tester, you must use extreme care to position the pointer exactly on the minor and major load marks.

Lastly, the correct Barrel dial setting – 

The upper line of the barrel’s hardness scales should be exactly aligned beneath the hairline on the magnifier.

Do you need to convert Brinell to Rockwell?  See our Rockwell/Brinell conversion chart.

 

Metal hardness chart scale Rockwell Metal Hardness Charts

Here are some commonly used scales on our models.

Frequently Used Rockwell Scales

Please contact us with any questions regarding proper maintenance and set up of our Rockwell testers.

 

Measuring Hardness Rockwell Scale

Hardness Testing in Rockwell Scales

Hardness Testing – Rockwell scales

Measuring Hardness Rockwell Scale

Rockwell Hardness testing is a system for determining the hardness of metals and alloys of all kinds. The American Society for Testing and Materials (ASTM) has established a standard recognized worldwide to help manufacturers maintain the qualities they want in their products. If you are using the Brinell scale check out our conversion chart.      

ASTM Standards E-18 and E-110 defines the test method and parameters for a valid test using portable hardness testers. Following is a general description of the method. A spheroconical diamond penetrator or a carbide ball penetrator is forced into the surface being tested at a predetermined pressure load. The hardness is read as a function of the depth of penetration.

To overcome errors in measurement, two pressure loads are applied in sequence. The first, a minor load is applied and the readout dial is “zeroed” with the part being tested still under load. Then the major load is applied.  The penetrator is backed out to the minor load point to read the distance traveled. The hardness reading represents the additional depth of penetration beyond the minor load.  Tester accuracy is checked by running the test on specimens whose hardness has been certified by an independent testing laboratory. All Ames hardness testers perform genuine Rockwell Hardness tests, giving a direct Rockwell reading. Their accuracy meets or exceeds ASTM Standards E-18 and E-110. Each tester comes complete with test specimens to assure continued accuracy. 

*All Ames testers are
factory lubricated. Do not
attempt additional lubrication.
Keep the tester dry and free
from oil. Store in the case
provided. When necessary,
wipe with a commercial
cleaner.

Maintaining accuracy with a portable Rockwell hardness tester

All AMES Hardness Testers, whether in constant use or not, require accuracy checks. To check accuracy, take the average of 5 readings on the test block. The readings on the barrel dial should agree with the marking on the test block, within +/- 1 point.
Further, to guarantee the accuracy of your tester, it is recommended that tests be made in high, medium, and low ranges. For example, C Scale, C-63, C-50, and C-28. Once per year, your tester needs to be factory calibrated. 

The distance between the center of two adjacent indentations shall be at least three times the diameter of
the indentation.  The distance from the center of any indentation to an edge of the test piece shall be at least two and a half times the diameter of the indentation. In other words, keep indentations 3 diameters apart. Indentations can only be made on one side of the test block.

Please check out our penetrators for hardness testing by clicking the link below

Penetrators for sale

Also check out more on how to properly use a portable Rockwell tester by following the link below

How to properly use a Ames Rockwell Hardness Tester

You may also contact us with any questions you may have. 

Rockwell-Metal-Hardness-Tester-Calibration

Portable Rockwell Hardness Tester Calibration – An Infographic

Rockwell-Metal-Hardness-Tester-Calibration

 

Don’t forget to calibrate your Ames Rockwell Tester once a year for continued accuracy

To get your Ames Tester calibrated or repaired please ship it to:

Stillion Industries
2055 N. Lima Center Rd.
Dexter MI 48130
United States

Please be sure to put your contact information in with the tester shipment.

Metal Rockwell Hardness Testing

How to Test the Hardness of Steel

Rockwell Hardness testing can be used for determining the hardness of soft and harder metals including steel. The American Society for Testing and Materials (ASTM) has established a standard recognized worldwide to help manufacturers maintain the qualities they want in their products.  ASTM Standards E-18 and E-110 defines the test method and parameters for a valid test using portable hardness testers. Rockwell hardness testing is a way of measuring the hardness of steel. Hardness means resistance to penetration. This test gets its name from Stanley P. Rockwell who invented the test and the original hardness testing machines.

Using the Rockwell method to test steel hardness

The Rockwell hardness testing of steel parts is done by applying loads to parts via either a tungsten carbide ball or a  diamond indenter.  The surface of the steel part has to be ready before the testing can begin.  If it is not, the chances of inaccurate readings rise.

Next, a light load is applied to the indenter or penetrator (usually either 3 or 5 kg) to zero out the portable Rockwell hardness tester. Next, a heavy load ( from 15 kg to 150 kg) is applied and held for a period of time.

The length the indenter traveled from the application of the light load to the release of the heavy load is documented and used to determine the hardness of the steel

Rockwell hardness is determined by measuring the distance traveled by an indenter when a heavy load is applied to a heat-treated part. The Rockwell method is the most common and accurate way to get a calculation on the hardness of steel

Take a look at the video below for further instructions on using an Ames portable Rockwell hardness tester.

Further reading

What metals can Rockwell hardness testers be used with?

How To Use A Rockwell Portable Hardness Tester

Using An Ames Portable Metal Hardness Tester

Find more helpful videos on our youtube channel. Below is a transcript of the above video.  If you have any questions or need more information on our portable Rockwell testers than contact us here.

We’re going to be testing a customer’s sample piece on her Model 1 a standard Ames portable hardness tester.  The purpose of this demonstration is to show you just how easy it is to operate the tester as a sample piece or using a small clip. It is a hard material spring-type steel.  I’m using a diamond penetrator for the flat Anvil.   I’m going to be measuring in the C scale which requires a 10-kg minor load and I’ve got a  150 kg major load.  First thing I want to do is initialize the Dow indicator Itself by rotating the setting of the stylus of the indicator. Next we’re going to trap the part between the Anvil and the penetrator and I’m going to establish my 10 kg. load. Simply do that by rotating the handwheel and the pin correctly. Next we want to establish the zeo point on the tester itself. To do that we  rotate barrel down and rest the pin directly on the magnifer. Next we will rotate the handwheel to 150. Once that is set, reverse the handwheel back to the set point. What you see is the C scale numbers in black and B scale numbers in red. We are looking at the C scale.  You can see the line underneath the number 40 there’s a thick line and then off on the left hand side there’s little hash marks each one of those small hash marks is 2 points.  The large broad line underneath the number itself is the whole number or in this case 40.  You can see it set up in 10 point increments.  So what we’re looking at is 40 which is the black line underneath the 40 and then we’re sitting right between the broad and hash mark which makes it a 41.  We want to thank you for your attention should you have questions please feel free to contact us by email telephone.

Below are a few videos featuring tips on how to use a Portable Ames Rockwell Hardness Tester. Make sure  to tighten extensions, penetrator and anvil. Also make sure the gage is set to the dot. When used correctly our metal  hardness testers are reliable for testing metals and plastics.

If you should have any questions on our portable hardness testers please contact us here.

The first thing we are going to do is, with no load applied we want to lift this needle and make sure it’s below that set mark and pointed right at the dot. The next thing we’re going to do is just make sure all our components are tight so starting with the anvil, the extension and the anvil adapter and finally our penetrator, just make sure all of those are finger tight.

7 Things you Should and Should Not Do When Caring For Your Rockwell Tester

Your Ames portable hardness tester is a precious instrument.  As with any tool, proper care and maintenance is essential to maintain accurate testing results.  Remember, annual calibration is essential to properly maintaining your teseter.  Our metal hardness testers and accessories are machined, assembled and calibrated in our facility located in Dexter Michigan.

Ames Portable Hardness Testers are Made in Michigan

We have compiled the following list of do’s and don’ts to protect your hardness testing machine and keep it in the best working order.

7 Things You Should Do to Properly Care for your Ames Portable Tester:

  • Spray WD- 40 on a soft towel to clean your tester and test blocks
  • Make sure the Penetrator, extensions, and anvils are tightly secured
  • Store your test blocks in the plastic bag that is provided
  • Store your Rockwell tester in a safe location
  • Send your tester back for a yearly cleaning and re- calibration (if needed)
  • Only use the appropriate anvil for the application.
  • Perform regular tests on your Ames Tester to ensure accuracy
    Ames 4-4 portable hardness tester with manual

7 Things you Should Not Do to Your Ames Portable Tester:

  • Never apply oil directly on the tester
  • Do not drop or bang your tester
  • Never exceed major loads
  • Never use both sides of the test blocks. (one side only)
  • Do not retract the spindle past the threads of the penetrator
  • Never bang the tip of the diamond into the part or test block
  • Do not over or under shoot the minor or major loads

Your Ames Portable Hardness Tester is guaranteed to last for years if you follow these recommendations.  Be sure to follow the directions in the manual included with your tester.  Store your tester and testing blocks in the case provided when it is not in use.  As recommended by ASTM, perform regular accuracy checks to your tester to ensure the readings are accurate.

This blog was updated on December 14, 2021