How to Choose a Grinding Wheel
If you’re looking to buy a grinding wheel for metalwork, there are several vendors you can find nowadays. But you need to pick the right one so you don’t end up wasting cash and time.
Many things should be considered when buying a grinding wheel, first of which is the material that you will use it on. This determines the type of abrasive you will need. For instance, aluminum oxide is recommended for steels and steel alloys. For non-ferrous metals, non-metallics and cast iron, you should get silicon carbide.
The harder and more brittle the material to be ground is, the softer the grade and the finer the grit size you’ll need. This is due to the fact that tough materials resist abrasive grains, causing them to dull quickly. With a finer grit and softer grade, the grains can break away as they turn dull, while fresh and sharp cutting points come to the surface. On the other hand, a coarser grit and harder grade are best for softer materials that are easy to penetrate.
The amount of stock that should be removed is also a factor. Due to heavier cuts and stronger penetration, coarser grits will obviously take out stock at a higher speed. But if the material is harder, a finer grit is better to use.
As to bonds, wheels with vitrified bonds, they are capable of higher-speed cutting. For removing tiny amounts of stock, shellac, resin or rubber bonds are advised.
Another consideration that should be made is the speed of the wheel during operation. In most cases, vitrified wheels are used for speeds below 6,500 surface feet per minute. Faster speeds can break the vitrified bond. Best for speeds of 6,500 and 9,500 surface feet per minute are organic bond wheels. When higher speeds are required, specially designed wheels are often necessary.
In any case, operating speed should not be higher than the maximum recommended in the manual.
The next thing to consider is the area of the wheel-to-workpiece grinding contact. Broader areas of contact mean a coarser grit and softer grade should be used. Because of the greater unit pressure, finer grits should be used for smaller areas of grinding contact.
Then, take into account the grinding action severity. This pressure is what keeps the grinding wheel and the workpiece close together. There are abrasives made to endure extreme grinding conditions when working on steel and steel alloys.
Lastly, grinding machine horsepower needs to be factored into your choice of a grinding wheel. Harder grade wheels must generally be used on machines that have higher horsepower.In cases where horsepower is less than wheel diameter, experts recommend a wheel of a softer grade. The reverse is also true.
The opposite is true as well.