Grinding wheels requires the precision in the selection of the grinding wheel based off the material, the machine, and the job to be completed. Selecting the correct grinding wheel are of the utmost importance because using the wrong grinding wheel can cause accident in the workshop or damage the workpiece. Grinding wheels cannot be interchanged; hence, understanding the different shapes, abrasive grain, and bonds in grinding wheels will allow the user to select the correct grinding wheel for the job.
The shape of the grinding wheel will determine how the grinding wheel come into contact with the workpiece. Straight grinding wheels has a flat disc that works along the outer edge of the grinding wheel. These grinding wheels create less heat during grinding, so they are used for surface grinding or sharpening tool.
How to Choose the Right Grinding Wheel and Stay Safe
Cup shaped grinding wheels allow the flat end of the grinding wheel to come into contact with the workpiece. These grinding wheels allow coolant to contact the workpiece more better and are used on heat sensitive workpieces. Recessed grinding wheels has one or both sides of the grinding wheel dipping inwards to clear the flanges of the machine.
These grinding wheels are used on cylindrical grinders to turn shafts and bearing. Depressed center grinding wheels have the full face of the grinding wheel that can come into contact with weld and rust. These grinding wheels are used for metal removal from welds.
Conical flap discs have flexible flap on the grinding wheel to allow it to conform to the contours of the workpiece. These grinding wheels are used for both cutting and finishing workpieces. The abrasive grain and the bond of the grinding wheel will determine how the grinding wheel interacts with the material.
If the material is ferrous metal, use grinding wheel with aluminum oxide abrasive grains. These grains are strong enough to self-sharpen as they remove metal from the workpiece. Use silicon carbide abrasive grains for non-ferrous workpieces, such as cast iron.
Silicon carbide is brittle and readily break down the metal. Use vitrified grinding wheel bonds for precision work. These bonds have porosity to allow coolant to enter the grinding wheel.
Use resinoid bonds for portable hand tool that experience shock vibrations. Safety is of the utmost importance when using grinding wheels. Every grinding wheel has markings that will tell the user the type of abrasive grains in the grinding wheel, the grit size of the abrasive grain, the hardness of the grinding wheel, and the maximum speed of the grinding wheel in revolutions per minute (RPMs).
It is important to ensure that the speed of the grinding wheel do not exceed the RPMs of the machine. Grinding wheels may have crack that are not visible to the naked eye. Performing a ring test on the grinding wheel will ensure that the grinding wheel is safe to use.
Ensure the grinding wheel is mount correctly with flanges. Always use a guard on the grinder when in use and ensure that the grinding wheel does not exceed its maximum speed. Cut-off grinding wheels are ultra-thin and used for slicing metal part.
Use cut-off grinding wheels only for making perpendicular cut to metal workpieces. Side-loading a cut-off grinding wheel can cause the grinding wheel to break. Another essential task is to match the grinding wheel to the workpiece.
Carbon steel will work best with medium grit aluminum oxide grinding wheels. Use zirconia grinding wheels for sharpening stainless steel as they will not leave any metallic contamination on the workpiece. Use diamond or green silicon carbide grinding wheels for carbide tool so that the tools stay sharp while grinding.
Aluminum metal is gummy and will bond with the grinding wheel. Use open-structure grinding wheels for grinding aluminum metal. Many people makes the mistake of skipping the proper selection of the grinding wheel.
Use the correct grinding wheel for the job and purchase one that is not too expensive as quality tool will last longer. Match the shape of the grinding wheel to the machine, the face of the grinding wheel to the workpiece, and the abrasive grain to the material being ground. Use a diamond tool to dress the grinding wheel regularly to expose fresh abrasive grain.
Grinding wheels will cut faster and will last longer if dressed regular.
