A bench grinder is a type of workbench-mounted grinder that has two grinding wheels located at the ends of the motor shaft. It is typically used to hand grind different cutting tools. Since its wheels are essential, we will be discussing how to change bench grinder wheels and get to know the origins of the grinding wheels.
Grinding Wheels: The History
Cousins Franklin Norton and Frederick Hancock opened a pottery business in 1858 and were mainly focused on redware and stoneware pottery. Eventually, they expanded to manufacturing items like jugs, spittoons, and beer bottles.
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In 1873, one of their employees, Sven Pulson, invented the kiln-fired grinding wheel that was shaped using a mixture of water, clay, emery powder. Frank Norton patented his employee's invention and began reproducing it.
Pulson's concept was revolutionary and surpassed industry standards. Such wheels eroded as they were used, resulting in a fresh cutting surface every time it was used. It was also cheap and efficient because it was manufactured rather than quarried.
So, in the late 1880s, the grinding wheel became an essential tool in every machine shop. However, in the 1890s the emery wheel was overshadowed by aluminum oxide and silicon carbide composites.
The emery wheel is still in use but more for polishing than grinding and shaping. Through the years, grinding wheels made from different materials were created and patented.
How to Change Bench Grinder Wheel: A Step-by-Step Guide
Before changing the bench grinder wheel, it is important to wear safety glasses. You should also make sure not to exceed the recommended torque level in tightening the bolt when securing the wheel. That is because such can lead to the possibility of the wheel coming off while you are using it. In addition, make sure that the replacement wheel has the correct size and speed rating for your speed grinder.
To change a bench grinder wheel, you will need the following tools:
Step 1: Safety first
Ensure that the bench grinder is unplugged from the main source. The backup power source should also be switched off in case it is connected to such. Likewise, if it's possible to remove the power lead, go ahead and do so to prevent any obstruction.
Step 2: Get to know your tool
Even if you already know how to use your bench grinder, it is still important to do a quick study of the tool that you will need to accomplish the task at hand easier. Therefore; examine your bench grinder to find out how it works and which part needs replacement. You can also check out the instruction manual once again because this should outline the full details on how you can safely detach and replace the wheel.
Step 3: Eliminate any obstruction
Most bench grinders feature a safety guard which needs to be taken off so you can remove the wheel quickly. To do this, you need to find the screws that help attach it to the main body of the machine. Then, carefully remove them using the proper screwdriver. After that, take off the safety guard completely instead of twisting it out of the way.
Step 4: Detach the wheel
Determine where the drive shaft of the bench grinder is, and with the use of a wrench, unscrew the nut and washer that anchors the wheel. Set them aside and make sure you don’t lose them. If it is stiff, apply a small amount of oil on the joint of the shaft and nut. Then, remove the wheel carefully but make sure you are wearing some gloves to protect your hand.
Step 5: Attach the new wheel
Place the new wheel the same way that the old one was positioned. You may need to make sure that you place the wheel the right way, depending on the type of wheel you are mounting. Like the previous wheel, slide the new one to the furthermost point that it can reach, and then, put the washer and nut.
Using a wrench, the nut should be tightened back into place. One important note is not to put too much force during tightening because this will naturally tighten when the wheel is in motion.
Step 6: Test the Machine
Test the new wheel by turning on the machine and watching the wheel turn. While doing such, listen for any unusual sound or movement. If you notice something different, like a wobble or noise, turn off the machine from the mains first before correcting the issue. Finally, if you see that it is already working properly, turn off the machine and place the safety guard again.
The bench grinder is one of the most important tools to have in a workshop because it can do a variety of things like sharpening dull tools, fixing broken blades and polishing and repairing small pieces of steel.
However, like all machines, some parts of the bench grinder need replacement, such as its wheel. This is imperative so that it can always do the things it was made to do correctly. Furthermore, this is part of the machine’s maintenance as well.
You may hire someone to do this for you but being the handyman that you are; this is something that you will be able to do on your own. Also, the steps on how to change bench grinder wheel, which is enumerated in this article, are simple and very easy to follow. You don’t need to be an expert to be able to do it.
The procedure also includes safety precautions so that you can prevent injuries while you are in the process of replacing the grinder wheel. In addition, it has the things that you will need so you can do each step easily. Finally, changing your own bench grinder wheel can be a satisfying endeavor. Therefore; doing it properly and safely is imperative.
Choosing the Right Grinding Wheel
To find the best wheel for the job at hand, you should know a few of the basic fundamentals of grinding wheels. A grinder is an abrasive cutting tool, so the wheel has abrasive grains. The abrasive grains are what does the cutting and is the bond that holds the grains together and supports everything while you are cutting.
Each different abrasive type has its own properties regarding hardness, strength, fracture toughness, and resistance. One of the most common abrasives used with grinding wheels is aluminum oxide. This is what is often used for grinding carbon steel, wrought iron, and other similar metals.
Zirconia alumina is another abrasive type that works well with steel and steel alloys, and silicon carbide is used for gray iron, brass, and softer bronze and aluminum. The newest addition to the world of abrasives is ceramic aluminum oxide, which is harder and stronger than the others and is more commonly used for precision grinding.
You will also find that the wheel comes in several shapes as well. Cylinder wheels, cup wheels, and dish wheels. Choosing a wheel shape is dependent on the job you are trying to accomplish. Smaller grinding wheels, for example, with special shapes are used permanently mounted and are used for a variety of precision cutting jobs.
Finally, consider the material that you are going to grind, the amount of stock that needs to be removed, and the wheel speed for the operation. Additionally, the area of grinding contact between the wheel and the workpiece should also be considered when choosing the best grinding wheel for the job.
Bench Grinder Wheel FAQ
What is a bench grinder wheel made of?
Grinder wheels are made from a variety of different abrasive types including diamond or CBN grains, aluminum oxide, silicon carbide, and ceramic grains.
How does a bench grinder wheel work?
Depending on the wheel you use, a bench grinder is abrasive and grinds each item it comes in contact with. It can shape, sharpen, buff, and clean almost any metal. Simply place the item on the grinder against the wheel at a 25 to 30-degree angle and keep it moving.
What is a vitrified grinding wheel?
These grinder wheels are most often used for precision grinding on materials such as ceramic, stone, marble, and glass.
What is a type 27 grinding wheel?
This grinding wheel is flat and perpendicular to the mounting hole on your bench grinder.
What is a wire wheel?
A wire wheel is used for cutting, cleaning, edge blending, polishing, and surface finishing. It is motor driven and features an arbor hole that supports its use with grinding equipment and machinery.
What is the grit size in a grinding wheel?
For a grinder, the grit is coarse or fine and usually runs from a coarse 16-24 grit, a medium grit of 36-60, and fine grit of 80-120. Most grinding wheels are usually between 24 and 100 grit.
Before you mount new abrasive wheels, should you visually inspect and ring test them?
Before mounting, you should inspect and ring test new grinding wheels. This is to find any defects there may be.