What is a bench grinder and how do you use it?
A bench grinder is at its hear a motor that spins two spindles, one on either end of the motor, extremely fast. Typically, the spindles are fitted with grinding wheels, which may have different textures for different purposes. For example, there are wheels with a fine or coarse grit coating for sanding or cutting, wheels designed for wire brushing metal, and wheels designed for buffing.
Once these wheels are spinning, you can gently edge a tool, piece of hardware, or other metal up the edge of the wheel to begin grinding it. Typically, working with metal will produce sparks and heat, so be sure to wear appropriate safety equipment and use a pair of pliers to hold small tools or hardware.
Size, power, and speed
The size, power, and speed of your grinder make a significant difference in what you can do with it. So when choosing a grinder, you need to match what projects you plan to use it for with these specifications. Smaller grinders unsurprisingly typically offer less power, but this isn’t an issue for most non-industrial grinding jobs – typical grinders offer plenty of power even for cutting through relatively thick pieces of metal.
Smaller grinders can be advantageous in that they take up less workbench space, but they also require greater precision if they use smaller diameter grinding wheels.
Speed is one of the most important things to consider, since sharpening tools – one of the most common uses of a grinder – goes much better at lower speeds in the 1,700 RPM range, while grinding and buffing works better at typical 3,500 RPM speeds. More expensive grinders offer variable speed settings, which can allow you to do all types of jobs with a single machine and is worth the investment for many people.
Construction and durability
While you might want your benchtop grinder to be as light as possible, you don’t want it to be too light – a sturdy cast iron base and stainless steel construction can dramatically improve the stability and durability of your grinder. These materials are nearly unbreakable and make it likely your grinder will last a lifetime. The best way to determine whether a grinder is made of high-quality materials is to check customer reviews, since users typically notice poor build quality immediately upon using the grinder.
Many grinders include some features in the design to minimize the vibration that occurs when using the machine. The vibration dampening may take the form of either a cast iron base, rubberized feet, or even a set of wheels under the grinder.
Guards and tool rests
Most grinders come with hinged glass guards directly over the exposed portion of the grinding wheel in order to limit the spray of sparks when grinding. These are extremely important for safety and should be used whenever you are grinding.
In addition, many grinders offer built-in tool rests that allow you to stabilize whatever tool you are sharpening as you press it against the grinding wheel. Cheaper grinders may have non-adjustable tool rests, which can be annoying, while higher-end grinders come with adjustable tool rests that can make getting precise cuts and sharpening angles much easier.
Modern high-quality bench grinders typically come with a work light – essentially a lamp that extends over the back of the grinder. This makes it much easier to see what you’re doing, especially if you work in a dark garage. However, this feature isn’t essential as you can easily opt to use a headlamp or a separate lamp. Note that some included lamps are too dim or too inflexible to be used effectively with the grinder, while others can only be turned on while the grinder is running – so be sure to check reviews about whether the light works as advertised.
Price and warranty
Bench grinders can range in price from just over $50 to several hundred dollars depending on the features they come with and the quality of materials they are constructed from. However, cheap doesn’t have to mean poor quality – if you are using a bench grinder for a relatively limited set of purposes and don’t plan to use it frequently, you may be getting more value with a low-priced grinder that gets the job done without having features you don’t need.
Another thing to consider when choosing among grinders is the length of the manufacturers’ warranties. While two-year warranties are common, some grinders come with warranties of up to five years – an encouraging sign that the company stands behind the quality of their grinder. Be sure to check the warranty text specifically, since many warranties are limited in scope and will only address manufacturing defects.