Tag: Ames

Why Hardness Matters When Choosing Drill Bits

Knifemakers and Saw manufacturers are among the long-term customers of Ames Portable Hardness Testers. This makes sense because the hardness of your cutting instrument is an essential part of marketing your product. Drill bits are no different. The hardness of your drill bit tells a lot about the length of time you can count on the cutting power of your drill. One local manufacturer of drill bits compares the hardness of cobalt and carbide drill bits. This comparison references Rockwell hardness, showing that the hardness test provided the necessary information for customers like you considering purchasing drill bits.

Carbide Drill bit, disintegrated carbide drill bit

What is the Hardness of your drill Bit?

According to the Tech talk carbide drill bits are of 75 HRC while cobalt drill bits are only 65 HRC. This makes the difference when using the drill bit because they last longer, are more heat resistant, and can improve your cycle times. On the flip side, carbide drill bits are more expensive, are harder to resharpen, and may need to be replaced when it is blunt.

Removing broken drill bits is no fun. Electro Arc metal disintegrator owners have experience with removing both cobalt and carbide drill bits. You may have experienced delays in manufacturing and machine downtime, due to a broken drill bit stuck in an essential part. Knowing your drill hardness can help you avoid this situation.

What is the Role of Hardness in Removing broken Drill Bits?

You can use Ames portable hardness testers to test hardness in just minutes. These testers are convenient because they can be used in tight spaces, like on the production floor to ensure your parts are the correct hardness. You can also plan to remove broken drill bits when you need to by having the correct machine on hand to do so. Cobalt and carbide drill bits, knives, and saw blades all have different hardnesses, so they will be different to remove. Our AC machines can remove your high-speed steel but you will need a DC machine to remove broken carbide drill bits.

As you know, there are lots of ways to check material for hardness, the most recognized is Rockwell. A wide assortment of portable testers are available on the market. Most of them can be converted to some sort of varying Rockwell reading. Electro Arc Ames portable hardness tester has been recognized across industries as a reliable, easy-to-use, accurate tester.

Some portable testers require manpower to hold the tester perfectly aligned and with enough force to get a consistent reading. Most of these testers use a spring-loaded penetrator shaft. This is fine but, if conditions are not correct, (misalignment, clamping pressure, surface finish, or material density), the test will be inaccurate and repeatability will be nonexistent. Ames Portable Hardness Testers, require no electricity and have a zero carbon footprint. The sling shot configuration securely traps the specimen between the penetrator and anvil allowing positive contact for the minor and major loads to be applied.

Accurately Reading a Rockwell Portable Hardness Tester

When you get a new Ames tester, it is important to practice with it as you would with any other measuring instrument. Ames accuracy testing helps you ensure that your hardness tester is reading accurately. Using your test blocks to verify the correct readouts on your Ames tester ensures the tester is working as it should. Making sure you are reading your Ames tester accurately is also important. Frequently used scales on Standard hardness testers are A, B, C, and E in the Rockwell scale. Superficial scales that are frequently used include 15-N, 30-N, 45-N, 15-T, 30-T, and 45-T. Familiarize yourself with charts for these scales and practice testing in the scale you will be using most frequently.

Frequently Used Rockwell Scales

There are two basic types of penetrators that you will be using to conduct your hardness tests. The ball penetrator comes in 4 sizes, be sure to check your chart for the appropriate penetrator. For example, if you are testing a soft material, you will likely be testing in the “B” scale and will use a 1/16″ ball penetrator. Never use the ball penetrator with your steel test block or when testing hard steel, this will damage your penetrator and give invalid results. For testing harder materials, you will use a diamond penetrator. Diamond penetrators are available for either a standard or superficial tester, all one size. Using the diamond penetrator on a softer material can ruin your material. If you are testing a harder material you will likely test in Rockwell C with the diamond penetrator.

When you set up your tester, be sure to secure the penetrator and the appropriate anvil. Check the position of the indicator hand. The indicator should rest directly on the dot on the dial. When you apply the minor load, slowly turn the hand wheel until the indicator points to the line marked “set”. Next, you will rotate the top of the barrel dial toward you until the pin rests against the magnifier. If you are using a model 1-4, there is no pin and you will need to align visually. Your Ames manual contains these instructions.

When you apply the major load, turn the hand wheel until the pointer rests on the major load indicated by the chart. You need to be careful to bring the indicator exactly to the desired graduation on the dial. If penetration goes beyond the major load you will not receive a valid reading and will not be able to receive a valid reading on that penetration. You will need to choose a new test point and begin the test again.

When you turn the handwheel back and bring the pointer back to “set” you can take the reading through the magnifier. Each graduation indicates two points on the Rockwell scale. If you are using a standard tester with a ball penetrator, read the black numbers in column “B”. If you are using a diamond penetrator, read the black numbers in column “C”. You may notice the first two or three tests may be low until your penetrator and anvil are seated.

In addition to practice and accuracy testing, it is important that you have your hardness tester calibrated at our facility on an annual basis.

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.