Wheel Size
There are two common sizes of bench grinders: 6-inch and 8-inch. That number refers to the size of the grinding wheel. You’ll also find smaller bench grinders—3 inches is fairly common—that are used primarily for crafts or other detailed work.
For the average DIYer, a 6-inch bench grinder is the right choice. These tools typically spin the grinding wheels at a set speed of anywhere from 3,400 to 3,600 revolutions per minute, and are excellent for sharpening knives and tools, grinding away paint, grime, or rust, sanding metal and wood, and other light-to-moderate repairs around the house or garage.
Eight-inch bench grinders are standard in automotive, woodworking, or metalworking shops, but some DIYers like them for home use, as well, particularly if they do a lot of work with metal. The wheels typically spin more slowly on these larger grinders—around 1,500 to 2,000 is a common range. Some have both a high and a low speed setting so you can choose the one that best suits your needs—slower for more control, faster when you don’t need as much finesse.
Wheel Type
Most bench grinders come with two installed wheels, and usually, those wheels will have different grits and be different types. Commonly, one wheel will have a grit size between 80 and 120 for handling light grinding tasks, and the other will be either a medium grit of 30 to 60 or a coarse grit of 20 to 24 for more aggressive work.
The most common wheel materials are:
- Silicon carbide: This common material is suitable for most grinding and sharpening tasks, but tends to heat up very quickly.
- Aluminum oxide: Another common material that’s especially suited to sharpening and grinding hard metals. Aluminum oxide doesn’t heat up as quickly as silicon carbide.
- Ceramic aluminum oxide: Excellent for a wide range of metals, ceramic aluminum oxide is long lasting, self-sharpening and not prone to overheating.
- Wire: These wheels are covered in steel or brass wire filaments. They’re used mostly for automotive repairs and bodywork, but if you do a lot of work with metal, this might be a useful choice.
- Buffing: These heavy cloth wheels are perfect for polishing, buffing, or shining up a wide variety of metals.
Power
You’ll find that some manufacturers state the power of their bench grinders in amps, while others use horsepower. As a general rule, 6-inch grinders have motors with around 2.1 amps of power—that’s around ¼-horsepower. Most 8-inch grinders have around 5 amps of power, which is roughly ¾ horsepower.
The most powerful bench grinders boast 1-horsepower motors, but these are generally used in industrial or professional settings, not for typical DIY projects.
What is a bench grinder used for?
While not a must-have tool for every DIYer, a bench grinder is more versatile than you might think. Along with its major use of grinding down metal, you can also use a bench grinder to sharpen tools, buff or polish metal, remove hardened dirt or other grunge from tools, cut metal or wood, remove rust, smooth and shape the edges of wood or metal, and even work on crafts such as jewelry-making or model-building.
Why does a bench grinder have two wheels?
Just about every bench grinder has two wheels, which serves to increase the versatility of the tool. Typically, bench grinders come with one sanding/grinding wheel with a light-to-medium grit for light sanding tasks and one sanding/grinding wheel with a medium-to-coarse grit for tougher grinding situations. But there are many wheels available for these tools, some quite specialized. You can swap out one or both of the wheels for a finer or coarser grit, a wire wheel for shaping or cleaning metal, a buffing wheel for polishing, a cutting wheel for wood or metal, specialized wheels for grinding or cutting stone, or even a specialized wheel for cutting gemstones.
Can a bench grinder be used on wood?
While grinding, shaping, and buffing metal are the primary uses of a bench grinder, you can absolutely use these tools on wood, as well. With the right wheel, your bench grinder can sand, cut, shape, buff, smooth, or polish a wide variety of woods. Typically, however, you won’t want to use a bench grinder for very soft woods; these tools are best used on hard materials.
This article is edited and updated by Michelle Ullman, the tool expert for The Spruce. She has extensive experience not only in writing about all things related to the home, but also in carrying out various DIY projects, including landscaping, painting, flooring, wallpapering, furniture makeovers, and simple repairs. For this roundup, she considered dozens of bench grinders, evaluating each for basic features, extras, and customer feedback.
