Category: Rockwell Hardness Testers

Hardness Testing for Knife Makers

Whether you are a hobby saw or knife maker, you may be wondering if you can use an old Rockwell hardness tester to test the hardness of your blades.  Many forums are full of comments from people just like you who have found old hardness testers at garage sales and want to know how to use them to verify their blad hardness.  There is a learning curve to using an Ames hardness tester, just like with any new measuring device. Yo can download the user manual for Ames testers for free and you will find all of the conversion charts you need to accurate reading no matter what you are testing.

Check out this in depth Demo of an Ames Hardness Tester from an Advanced Knife Maker:

As a knife maker, you may have used a hardness tester to perform hardness tests on your knives or saw blades.  Ames portable hardness testers are a preferred model for blade makers to perform quick hardness tests.  Many knife makers may not have the budget to purchase a new Ames Portable Hardness Tester.  Used testers available on eBay and Facebook marketplace can be appealing because of their discounted price.  It is important to check the serial number of a used hardness tester before you purchase it.  Old hardness testers may serve the purpose you are looking for: A basic hardness test.  However, it is important to know that you may not be able to have the tester certified when it is repaired if it is too old.

The frames of old hardness testers can fatigue, which will not allow the tester to perform an accurate hardness test, even with calibration you may find that the hardness readings don’t stay accurate.  This is why we recommend you look for hardness testers that have a serial number of 12000 or newer.  You should always turn the tester over and check the sticker on the back.  Every Ames factory-calibrated tester has a sticker telling you when the next calibration should be performed.  Another way to determine if your used tester is a good buy is to perform accuracy testing.  You can use the test blocks provided with the tester to make sure the readings are accurate.  Make sure you are using the correct penetrator for the scale you are reading in.

Grismo Knives demonstrates Testing Blade Hardness with Ames Testers:

Are Durometers the same as Hardness Testers?

Durometers are designed to be used with plastics while hardness testers can be used to test the hardness of most materials

Hardness testers may also be referred to as durometers. The main difference between these two instruments is the materials being tested. Durometers, generally test soft materials, while hardness testers are designed specifically to test the surface hardness of materials ranging from plastics to metals like steel. Some testers have been modeled and branded for their hardness testing scales. Hardness testers may be large and stay in a fixed location – bench testers, other testers are designed for portable use such as the Ames portable hardness tester. In 1812 Friedrich Mohs developed a scale to identify the hardness of minerals, ranking them on a scale of 1-10. The Mohs hardness scale has identified minerals’ hardness and known objects that minerals can be tested against to determine the hardness. This is the oldest known hardness measurement system.

The Shore Scales are used in testing the hardness of plastics – Consisting of Shore 00 for super soft materials like gum through Shore D for hard plastics and rubbers. The scale was designed by Albert Ferdinand Shore in 1920 although his tester was not the first device to be called a durometer. The Shore durometer was designed specifically to test polymers, elastomers, and rubbers. The shore scales provide a universal reference for a large scale of non-metal hardness testing.

The Scleroscope hardness tester was developed in the same time period as Brinell by Albert Shore of Shore Instrument Manufacturing Company, this instrument did not use traditional penetrators, but a scale to measure the material’s elasticity, this instrument was replaced by more accurate and efficient forms of testing as technology advanced.

Vickers durometer This use of the durometer refers to the hardness test, not the instrument. This scale is popular in the UK and Europe and is one of the widest scales for hardness testing. The Vickers hardness test also referred to as the microhardness test procedure was developed in 1921 by Robert L. Smith and George E. Sandland at Vickers Ltd as an alternative to the Brinell method to measure the hardness of materials from ceramics to metals.  HBW (H from hardness, B from Brinell, and W from the material of the indenter, tungsten (wolfram) carbide). In former standards HB or HBS were used to refer to measurements made with steel indenters. The Vickers test uses a smaller indenter making it easier to use on materials like foil and other very thin materials. Also, the required calculations are independent of the size of the indenter, making calculations easier. The basic principle, observes a material’s ability to resist plastic deformation from standard sources. The Vickers test can be used for all metals and has one of the widest scales among hardness tests. The unit of hardness given by the test is known as the Vickers Pyramid Number (HV) or Diamond Pyramid Hardness (DPH). The hardness number is determined using the load over the surface area of the indentation, not the area normal to the force, so it is not actually pressure. The hardness number can be converted into units of pascals, but should not be confused with pressure, which uses the same units.

The UCI (Ultrasonic Contact Impedance or Portable Vickers Procedure) hardness test is newer, developed in 1968 by Claus Kleesattel. This portable testing method uses the Vickers hardness test method described above which requires the use of a diamond indenter according to ASTM standards.

This method uses a 136-degree diamond at the end of a vibrating rod. The rod is depressed into a fixed surface and a fixed load is applied, the ultrasonic vibration frequency is then measured and calculated into a hardness value. This hardness testing procedure is used for measuring the hardness of small items, objects with a wall as thin as 1 mm, can be used to test hardness on complex forms, and measures the hardness of surface hardened layers. The indentation is considered less destructive than other testers making this a popular option.

The Knoop method is an alternative to the Vickers technique. Developed by Fredrick Knoop at the National Bureau of standards (now known as NIST) in 1939. Primarily used for thin materials with the risk of cracking like ceramic and in cases where a thin layer like a coating needs to be tested. This microhardness testing method uses a narrow diamond-shaped indenter. Knoop is the preferred method for small long test specimens whereas the Vickers method is more effective on small round pieces. The Knoop method is time-consuming and requires preparation of the test piece. Readings can be impacted by load, temperature, and environment as well.

The Brinell hardness test is the oldest hardness test, developed by Sweetish engineer, Johan Brinell. this hardness testing method can be used on rough materials and is performed in a standard or non-standard method. Irregular surfaces do not impact the outcome of this hardness test and can be used to test the hardness of components made from powder and cast. This scale can be used to test both soft and hard materials hardness such as tin, steel, and iron. Some restrictions of this method include, it can not be used on smaller objects, it creates a deep impression and the test can only be performed on a flat surface. This method is also time-consuming and has a higher rate of error in conducting measurements. A variety of hardness testers are available on the market providing Brinell hardness tests.

A popular standard in the hardness testing industry is the Rockwell scale. Developed by Stanley Rockwell in the early 1900s, the scale uses the indentation of a smaller steel ball than the Brinell method (less than 4mm) or a diamond cone to create and measure penetration and determine hardness. This test can be performed quickly. No preparation is required on the material, the scale is easy to read and requires no extra equipment which makes it the most commonly used hardness testing method. You can test the hardness of soft and hard metals in the Rockwell scales, the portable testers allow onsite testing quickly and easily. The Rockwell hardness test is standard on a variety of testers, bench top models were developed by Stanley Rockwell and developed by the Wilson-Mauelen company, acquired by Instron corporation in 1993. The Ames portable hardness tester was developed in 1947 and sold by Ames Precision in Massachusetts until Electro Arc purchased the product line in 1975. These Rockwell hardness testers provide portable hardness readings in the Rockwell scale, and a conversion chart into the Brinell scale.

Why you Need a Superficial Hardness Tester

Why choose a Superficial Hardness tester?

Superficial testers are designed to test very soft and very thin materials and are designed to leave minimal surface distortion.  The three reasons to choose an Ames Superficial hardness tester are, you are testing a very thin or soft material, standard superficial testers will destroy these materials or the test will show the hardness of the penetrator.  This test will leave a less noticeable mark on the material you are testing.  The superficial tester uses 15, 30, and 45 kg weight to measure rather than 60, 100, or 160 kg as with a standard hardness tester. 

Use the Rockwell “N” scale to test Hardened steels, case hardened steels, and hardened strip steels down to about.006″ thick, and when you need to keep the mark left behind by the tester to a minimum.  Use the Rockwell “T” scale to test soft steels, copper, and aluminum alloys.  You can use an additional ball penetrator to test in Rockwell “W”  for some hard thin material down to .006″ thick and cemented carbides.  Rockwell “X”  and “Y” scales are used for testing plastics.  The model 1-ST is designed to test small-diameter and thin-walled tubes.  Using Rockwell “15-T” to test tube materials like aluminum, thin steel, lead, iron, titanium, copper alloys, and cemented carbides.

Industries such as aerodynamics, steel plants, stamping manufacturers, electronics, appliances, and air conditioning part manufacturers use these superficial testers because their components are super soft and thin.

Superficial and standard hardness testers operate in the exact same way.    The major difference is the material tested and the  Rockwell scale you are testing in. You can purchase an Ames superficial tester in most of the same sizes as standard testers, with the exception of the model 8 and 16 testers, there is a like tester in the 4 main sizes of superficial testers:

Model 1-S and model 1 Ames testers are the same size.  They have an opening  1 inch wide and a depth of 1 inch, so they are ideal for testing smaller parts.

The model 2 and 2-s are the same size and have an opening of 2 inches with a depth of 2.115 inches. 

The model 1-4S and model 1-4 are the same sizes featuring an opening of 1 inch and a depth of 4 inches, great for longer, thin materials.

The model 4-4S and model 4-4 testers are the same size 4 inches wide and deep to allow you to test larger materials

The only tester with no standard equivalent is the model 1-ST, a special tube hardness tester.

What Comes with a New Ames Portable Hardness Tester?

A Look at the Ames Portable Hardness Tester Kit

The Ames Portable Hardness Tester case is made from high impact plastic, lined with foam to keep your Ames Portable Hardness Tester safe in transit.  There is a space for your Ames Portable Hardness Tester, 3 test blocks, penetrators and anvils in this case.  You may also choose to purchase one of Ames limited edition Model 1 testers in the original wood box.  This is a new tester in the old style box which was discontinued.

Of course your Ames kit will include the Ames Portable hardness Tester you have selected.  We manufacture Standard hardness testers which include the Model 1, Model 2, Model 1-4, Model 4-2, Model 4-4, Model 8 and Model 16 which test in Rockwell A, B, C, D and F scales, if you use them with our optional ball penetrators, they also test in Rockwell E, H, L, M, R, S and V scales as well. Our Superficial hardness testers include Model 1-S, Model 1-ST, Model 1-4S, and Model 4-2S which read in Rockwell scales N and T.  Using the additional ball penetrator they can also read in W, X and Y scales with the exception of the Model 1-ST which only reads in 15-T for tube testing. The only tester that does not include a carrying case is the model 16. 

Your kit will include a flat and a “V”anvil.  Anvils aid you in ensuring your tester provides valid readings.  The standard flat stock anvil is our most used anvil as it is designed for use with flat stock.  The “V” anvil is for small, round stock. Anvils are interchangeable.  We also sell raised flat anvils for thin stock, convex anvils for tube stock, round anvils for larger round stock.

You will receive one diamond penetrator and one ball penetrator in your Ames Portable Hardness Tester kit.  These penetrators are interchangeable.  You will need a different penetrator depending on the scale you are testing in.  Diamond penetrators are necessary for harder metals.  You can always purchase replacements on our website.

You will receive one hard steel, one soft steel and one brass test block with your Ames Portable Hardness Tester kit.  These testers help you with accuracy testing to ensure your tester is reading correctly.  Each Ames test block includes a certificate of calibration.  Superficial test blocks are standard with our superficial testers, and standard test blocks come with our standard hardness testers.  You may special order test blocks as well.

Ames hardness tester kits come standard with two extensions, one 1″ and one 1/2″ extension.  

Each Ames Portable Hardness tester includes a manual for use of your hardness tester.  If you lose your manual or need another copy, you can download it from our website at any time.  It is important to review this manual for proper care of your hardness tester, it also includes conversion charts for your use. 

Every Ames tester is factory calibrated before it is sold and every tester comes with a certification of calibration, our Ames test blocks include certification to the hardness on the test block.  Our testers meet NIST and ASTM E-110 standards.  You should return your tester to our factory for calibration once a year to ensure it continues to read accurately.  We also offer repair services.

What Ames Compliance Means for You

ASTM and ISO are standards designed to ensure traceability and repeatable accuracy. Our testers give accurate measurements in both large and small plants.

What is traceability? This term is indefinite as applied to relationships between calibrations and measuring activities of manufacturers and suppliers. Uncertainty concerning the validity of calibration data arises because of drift, environmental effects, transportation, and use. To provide support for the current validity of a calibration or to otherwise provide a basis for estimating accuracy, other procedures may be important or essential. Such as, the analysis of performance records of the instrument, local intercomparisons with other limits, checks the calibration at discrete points by the use of standard materials or devices, application of statistical methods in analysis of repeated measurements and in planning of measurements to determine or minimize the effects of disturbing variables, determination of measurement agreement between laboratories and the use of information related to the design and performance characteristics of the instrument.

hardness tester

The Ames portable tester uses the penetration method of testing and is based on the Rockwell principle. A diamond penetrator is forced into hardened steel and hard alloys and a ball penetrator into soft steel, nonferrous metal and gray and malleable iron castings. Pressure to the penetrators is applied to screw action, caused by turning the large operating wheel. A supersensitive dial indicator has graduations on the dial that indicates when pressures of 10, 60, 100 and 150 KG have been applied.

 

 

The portable hardness tester has a wide field of applications. Its use on a wide variety of hardness testing jobs is facilitated by the use of attachments. An extended V anvil is used to test small diameter round stock. The special spindle is used to keep the spindle from extending nearly full length from the tester frame and to prevent the penetrator from riding off-center. Larger round s are tested with a V anvil which is supplied as standard equipment with each tester.  Small rounds are difficult if not impossible to test the accuracy of tests drops sharply on diameters under 3/16 in.  Tables and charts have been worked out showing the degree of accuracy attainable in small diameters.

The hardness of full lenth sheets of steel, brass, aluminum, tin plate and the like are tested without the necessity of cutting off coupons or specimens.  Because of that fact, warehouses are finding such testers useful for checking quantities of sheet stock.  Some manufacturers use portable testers for checking the hardness of sheets before they go through pressure because one sheet of hard stock may breakdown valuable punches and dies.

Repeatable accuracy means repetitive tests on the same material will result in the same reading.  This benefit is not generally available on competitive portable testers.  No loss of accuracy is experienced when transferring readings into the Rockwell scale because all readings are made directly into the Rockwell scales.  The accuracy of Ames testers may be favorably compared to the accuracy of large bench-type testers when testes are performed in the same environment.

Ames 4-4 portable hardness tester with manual

5 Benefits of using Ames Portable Rockwell Hardness Testers

Do you wonder if Ames portable hardness testers are the best option for you to use when testing the hardness of metal? Here are 5 reasons to choose Ames when you choose your hardness tester.

  1. Ames provides you with repeatable accuracy. Repetative tests on the material will give you in the same reading. You may not find this benefit generally available on competing hardness testers. You will experience no loss of accuracy when you transfer your readings into Rockwell scales. This is because all readings are made directly into Rockwell scales. Ames tester accuracy may be compared to the accuracy of bench-type testers when you perform tests in the smae enviornment.
  2. Ames hardness testers are simple for you to operate. Even unskilled users can learn to make accurate tests after a very limited period of practice. This means you do not need highly qualified inspectors to make hardness tests. This allows you to perform hardness testes more frequently, and provide your customers with maintenance and closer tolerances for their products.
  3. Portable testers can be taken anywhere. With hardness testers that are not confiened to the labratory you can perform hardness tests on material at the assembly line, in the receiving yard, or on material still assembled in the machine. You will avoid delays in production. You can also perform hardness tests in scenerios that are not accessable for use with bench style hardness testers.
  4. Test in Rockwell A, B, and C. Ames portable hardness testers allow you to test directly in regular Rockwell A, B and C scales, or in Rockwell Superficial N and T scales. You can simply change the penetrator and the major load and your tests can be made in Rockwell D, E, F, G, H, K, L, M, P, R, S and V scales. You can refer to the following conversion chart for Rockwell Hardness. Ames’ extensive line of portable hardness testers allows you to test material in a size range of 1mm to 1 meter in diameter.
5. Ames testers perform rapid tests. You can perform a single test in less than one minute. Ames portable hardness testers are faster to use than bench-type Rockwell testers. It is of particular value when numerous repetitive tests are required on the material.

Ames Model 16 Solves Super-Size Quality-Check Problems

Model 16’s chain clamp system and dual “V” anvils allow testing round items from zero to16 inches in diameter. For testing Rockwell A, B, C and other scales. This tester can be ordered in standard or superficial versions. The measuring head is independent of the clamp and may be removed for mounting on a holder of your own design. This tester weighs 8 pounds and conforms to ASTM standard E-110.

Ames Precision Model ST allows you to Check the Hardness of Tubing in Rockwell Scales

In May of 1977, Ames announced the release of the Ames Model ST portable Hardness Tester. This superficial tester is specifically designed for testing small diameter or thin wall tubing. The small anvil will fit into the inner wall of tubing as small as 3/16″ and is effective in checking larger sizes as well. The tube hardness tester reads in the 15-T scale and comes in a high-impact case just like our other portable hardness testers.

Original promotion for Ames Model ST – Tube Tester

The Ames model ST tubing tester uses a special cylindrical anvil to test soft tubular materials such as copper. This tester is recommended for small diameter tubing with thin walls. The maximum load for the model ST is 15 KG, anything greater will damage this tester.

Before you begin a hardness test using your model ST, be sure that the 1/16 ball penetrator is snuggly screwed into the end of the tester spindle shaft. The 1/18″ pin perpendicular to the spindle is the anvil.

How to use your Model ST Tube tester:

Step 1: Rotate the bezel (outer ring of the dial indicator) and position the face of the dial so that the dot on the face is directly below the indicator’s pointer hand.

Step 2: Position your part over the 1/8″ anvil and slowly rotate the handwheel until the penetrator makes contact with the part and moves the pointer hand on the dial indicator to the line marked set. Stop at this point. You have reached the minor load point (3 kg).

Step 3: Rotate the numbered aluminum barrel dial, so that the 1/16 inch pin rests on top of the lucite magnifier.

Step 4: Rotate the handwheel until the pointer hand on the dial indicator reaches the major load of 15 kg (do not over or undershoot the target). Immediately after reaching the major load, rotate the handwheel back to the “set” (minor load) position.

Step 5: To read the Rockwell hardness, find the fine line on the magnifier. The scale below the magnifier on the aluminum barrel is graded in units of 10. The short hash marks are in units of two.

Is my Ames or DoAll Portable Hardness Tester Eligible for Repair or Calibration?

The Electro Arc company obtained the Ames Portable Hardness Tester line in 1975 and began manufacturing the standard and superficial hardness testers and accessories. For a short period of time, the company also made Fowler Hardness Testers and in the mid 1980’s through the early 1990’s also made DoAll portable hardness testers. Ames is now a Stillion Industries product line, continuing to make and service all Ames Portable Hardness Testers and DoAll hardness testers with a serial number of 12000 or newer. Some DoAll Hardness testers were issued with serial numbers starting with 17 by mistake and these testers may not be eligible for repair or calibration.

Ames precision is based on the flex of the Ames Frame during hardness tests. Over time, the portable testers are no longer serviceable, they must be replaced. If you are considering buying a used Ames, DoAll or Fowler portable hardness tester, it is strongly recommended that you check the model number to determine if your tester is new enough to receive calibration or repair service.

DoAll Portable Hardness Testers are identical to Ames portable Hardness testers with the exception of the dial indicator which bears the DoAll Precision logo.

When determining if your Ames or DoAll precision tester can be calibrated or repaired, look at the model number engraved into the frame of the tester. If your portable tester does not have an engraved model number, chances are, it is not a genuine Ames Portable Hardness Tester. You can always call us with your model number because we have records of every portable hardness tester made and sold by Ames.

All portable hardness testers made and sold by Electro Arc, and now Stillion Industries feature the model number in the same place. DoAll and Fowler hardness testers also followed the same pattern. If you are planning to send your tester in for calibration or maintenance please be sure to include your company information with the tester when you send it.

Ames portable hardness testers collection

Benefits of Using a Hand Held Rockwell Hardness Tester

Hardness calculations on metals and a are important for the manufacturing of different things: from automobiles to electrodes. Hardness qulaity control is used in various fields like machine engineering, metallurgy, mining and energy resource extraction.

Metal hardness measurements are performed with the help of stationary or bench and portable hardness testers. The operating principle of stationary hardness testers on Rockwell scales are described in the standards on the corresponding methods. Hardness tests on stationary hardness testers are direct measurements. Consequently, hardness tests performed using these methods are more accurate than the measurements via indirect methods.

Hardness tests on portable hardness testers are indirect measurements. Most portable hardness testers use the ultrasonic contact impedance method. The result of measurements on portable hardness testers is recalculated into hardness values on the Rockwell scales. Usually portable hardness testers have the following error limits of hardness measurements: ± 2 HRC on Rockwell scales.

The following is why portable Rockwell hardness testers have an advantage. Portable hardness testers are significantly lighter, they can measure hardness directly on a manufactured detail and in hard-to-reach places. Portable hardness testers are the only hardness testers suitable for conducting measurements in the field. One portable hardness tester enables the user to obtain hardness values using at least three different methods. The cost of portable hardness testers is lower than that of stationary ones. Important characteristics of portable hardness testers are repeatability and reproducibility of measurements. Despite relatively modest accuracy in comparison with stationary hardness testers, portable units have high reproducibility and repeatability and can be successfully used for components screening, control of the product homogeneity on hardness, as well as measurements in the field

There are several other ways for hardness to be measured, but the Rockwell test is the easiest one to perform. The portable tester provides an accurate measurement that can then be converted to a number on the hardness scale. The device is also highly versatile, and metals of nearly any size and shape can be used

Call or email us with any questions.

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UK +44 (0) 1384 231535

Email U.S. @ sales@electroarc.com
UK @ sales@electro.co.uk