Ames Portable hardness testers

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.


Portable Rockwell Hardness Testing is Easier With the Bench Stand

Rockwell-Hardness-Tester-Bench-StandSince 1947 Ames has been providing top of the line portable Rockwell hardness testers for the hardness testing of various metals. Not only are we committed to ensuring the accuracy of our machine’s measurements but we are also committed to helping our customers get the job done in a safe and convenient manner. Today we are showing off our popular 100% cast iron bench stand.

Ame’s Bench stand helps the user get an accurate reading by taking out all the awkward and difficult issues when trying to test your equipment.

  • Cast iron for solid support
  • Holds tester at a convenient angle, freeing hands for ease of use
  • Internal fiber sleeve protects handle
  • 11 lbs.



Looking for instructions on how to use our tester? Click the link to view or download our famous Rockwell tester manual.


Rockwell Hardness Tester Manual

For more information or to see all our Rockwell hardness testing accessories follow the link below.



Stillion Industries Acquires Ames Hardness Testers

Exciting news for our customers!

As of July 1st, 2019 Stillion Industries has acquired Electro Arc Manufacturing. This is good news for our customers. Alongside Stillion Industries, Electro Arc now has state-of-the-art ISO9001:2015 compliant machining and on-site engineering. With Electro Arc’s long history of quality product lines and Stillion Industries’ expertise in machining, we are positioned to make both companies reach new heights.

The move coincides with the retirement of Harold Stark, Electro Arc’s President/CEO since 1958, and ensures the continuation of Electro Arc’s tradition of quality.  Stillion Industries, active in the Ann Arbor area since 1972, brings expertise in machining as well as manufacturing know-how from Dexter Manufacturing Incorporated, which joined Stillion in 2014.

We have retained all employees from Electro Arc, doubling our workforce to maintain the long history and experience of both companies. Electro Arc has been in the Ann Arbor area since 1947 Stillion Industries since 1972. Electro Arc Manufacturing includes the Ames Hardness Tester and Uni-tek metal disintegrator product lines. The acquisition will ensure we are here to stay and we are committed to customer service.  We at Stillion Industries feel Electro Arc, Ames and Uni-tek are time tested superior products. We are committed to providing great customer service and a high quality

We look forward to your ongoing valued business as we continue to provide a quality product.

Stillion Industries

Keith Stillion



Portable Rockwell Hardness Tester Calibration – An Infographic



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 kgf) to zero out the portable Rockwell hardness tester. Next, a heavy load ( from 15 kgf to 150 kgf) 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?


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

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The Rockwell Metal Hardness Scales Explained

The Rockwell hardness test is used to test the hardness of materials. The Rockwell test is usually performed on metals ranging from thin steal all the way to harder metals like Titanium. However, there are multiple scales to test in and these are identified by a letter ranging from A-V  Each scale uses a different indenter and load to perform the test.

The equation for the Rockwell hardness test for metals is below:  d=depth from zero load point.  N and s = various scale factors that can be found in the chart below.

Rockwell A scale

Used to test: Tungsten carbide.

Rockwell B Scale

Used to test: aluminum, brass, and softer steels

Rockwell C Scale

Used to test: harder steels.

There are other scales that are associated with a Rockwell superficial test. These scales use a lighter loads and shallow impressions to perform the test. These are used on testing very thin metals.

Ames Superficial Hardness Tester
Note: There is only one row of dial numbers for the Ames superficial tester.

Get an Accurate Reading With Ames Rockwell Hardness Test Blocks

To ensure your Rockwell metal hardness tester is performing at it’s highest efficiency they should be tested on our test blocks everyday.

Our test blocks come in:

  • Brass

  • Hard Steel

  • Soft Steel

Ames offers the best quality hardness test block selection in the industry. If you don’t see what you’re looking for, please call our sales department. All of our Rockwell test blocks:

  • Come with certification.

  • Calibrated and meet automotive and aerospace standards.

  • Calibrated and meet ASTM standards.

Our test blocks are manufactured to provide our customers who need the best when it comes to quality control.  Matching specific blocks to a specific penetrator, a set relationship is established, and they can be eliminated as potential variables in the hardness test system. When an issue comes up our blocks work to quickly and accurately determine whether your Rockwell hardness tester is the source. Each block has been calibrated on a tester whose accuracy has been verified using N.I.S.T. traceable load and depth measuring devices. The individual test blocks are marked with their own unique serial number.  More information available upon request.

Call or email us with any questions.


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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.