What Is A Bench Grinder Used For?

A bench grinder is used for a wide variety of grinding, cutting, sharpening and shaping needs in both metal and wood fabrication.

Although uncommon in auto shops, having a bench grinder can significantly improve your work process when dealing with metal fabrication. 

So, what is a bench grinder used for and who should consider investing in one? Below, we discuss all the popular best uses of a bench grinder, including tips to help you stay safe and protect the equipment. 

Features of a bench grinder

what is a bench grinder used for

Bench grinders feature a powerful grind wheel that performs the hard work of grinding, cutting, or polishing. The wheel comes in varying coarseness and materials depending on the intended use.

Typical bench grinder wheels measure from 6 to 10 inches and are installed on the bench, or bolted on custom worktables to achieve precise cuts and angles. 

When looking to purchase a bench grinder, it is essential to determine the ideal wheel size. Other essential features to review include:

#1 The motor of a bench grinder

This is the most important feature to review before purchasing a bench grinder. The motor, which occupies the middle part of the unit, determines how effective the grinder will perform.

If you are working with hard metals, such as steel, it is recommendable to use grinders with a powerful motor with higher rpm (revolutions per minute). 

Most bench grinders average at 300 to 360 rpm, but you can find grinders with higher or lower revolutions. Essentially, the higher the rpm, the faster you can get the job done.

#2 Wheel guards 

The wheel guard or spark deflector is another critical feature of any bench grinder. As the name suggests, the spark deflector prevents exploding fragments and sparks from reaching you. Almost all grinders will produce wood or metal fragments depending on the material you are working on. 

Without a guard, these flying fragments can cause bodily industries or even damage the grinder. Some models come with a spark guard, while others will require purchasing them separately. The wheel guard usually covers up to 75% of the grinding wheel.

#3 Eyeshield and tool rest

It is recommendable to purchase an eye shield, the protective feature offering better cover for your face. It is mounted above the grinding wheel and can be used with other eye protectors, including glasses.

A bench grinder tool rest is also inseparable from the unit as it holds the workpiece in place when fabricating the metal. 

While it isn’t considered a safety feature, the tool rest prevents your workpiece from slipping and holds it momentarily. It also allows quick adjustments when shaping and sharpening the workpiece.

#4 Grinding wheels 

Grinding wheels do the hard work and come in different specifications to suit different applications. There are different types of grinding wheels available for working metal and other materials.

The size, grit (coarseness) and material used also vary, so you should determine the required specifications for your task. 

All wheels have a maximum rpm that you shouldn’t exceed, as over-speeding may result in explosions and injuries. You will probably need different grinding wheels for different uses (grinding, sanding, polishing and sharpening).

Top Five Uses Of A Bench Grinder

best bench grinder

Here are the five popular uses of a bench grinder machine:

#1 Grinding

Grinding seems to be the obvious use of a bench grinder. The grindstone wheels are used to grind material quickly and come in different coarseness to meet different applications. There are various kinds of grindstones available in the market, including those designed for hard metal and steel. 

It is recommendable to avoid using grindstones meant for hard metal on soft materials like aluminium. This is because the fine particles may lodge in the crevices on the grindstone.

The fragments may dislodge later when working at high speed, causing fatal injuries. Similarly, you shouldn’t use soft metal grindstones on hard materials as it simply won’t get the job done.

The edge of the grindstone will wear gradually, so it is essential to dress your stones periodically for effective grinding. Coarse grit offers the ideal solution for fast-paced projects as it grinds surfaces much faster than smoother grits.

However, each option has its unique uses. Grinding usually requires coarse grindstones, which also reduce heat build-up when working metals. 

Moving the workpiece around or dipping it in cold water can also reduce heat, ensuring safety and comfort when grinding metal surfaces. Wheel grinders are designed for grinding metal surfaces but can work other materials, including wood and concrete.

#2 Sharpening Blades And Other Metal Objects

Some grindstones are designed for sharpening rather than grinding. However, the process isn’t any different, since it involves grinding away the bent surfaces of a metal object.

Bench grinders can sharpen a wide range of metals, including lawnmowers, saw blades, chisels, cutting blades, knives, household blades and more. 

It is advisable to choose white grindstones, which do a better job at sharpening than their grey counterparts.

Sharpening also requires a different technique, usually slower rpm and overall process. A slow sharpening speed reduces heat build-up at the edge of the tool. Most blades and cutting tools are made using heat-hardened steel.

Working at high speed may result in overheating and ultimately grind the outer surface, exposing the soft metal inside.  Overheating can also damage your grinder, especially if the fine fragments find a way into the unit’s critical parts. 

When using a bench grinder to sharpen your tools, it is important to ensure a solid grip from the tool rest. The metal should be held in place to avoid sliding and approached with caution to prevent accidents.

Wheel grinders do a better job of sharpening metal objects that already have a defined cutting edge. They won’t suffice for blunt surfaces that need more grinding to form your cutting tool’s sharp edge.

#3 Cutting

Bench grinders can cut both metal and wood pieces. However, you need to be very careful when cutting wood using a grinder as it can catch fire easily or even split along the grain damaging the entire workpiece.

Metalworkers widely use bench grinders to cut metals of thin to moderate thickness. The technique involves turning the workpiece gently upon contacting the grinding wheel. 

You are required to continue turning the workpiece until it splits. Grindstones used for cutting are generally smaller or have a narrow girth to achieve slim cuts. Using a wide stone will eat away a big part of your metal of wood.

Although bench grinders are excellent tools for cutting thin materials, the procedure requires precision and precaution. You must keep turning the piece to achieve clean cuts.

If the material is overheating, you can dip it in water to temper hot edges or pause the grinder for a little while, especially if you are cutting wood pieces. 

The grit’s coarseness will depend on the material being worked, so you should determine what grindstone is ideal for cutting. You might also require additional grinding, buffing and polishing to smoothen the rough cut edges. 

#4 Buffing And Polishing

Buffing is another procedure you can accomplish using a bench grinder. This standard procedure is used to retain the texture of metals and other surfaces during fabrication.

Buffing involves using soft grit to remove fine fragments and polish the surface of the workpiece. You should ensure a firm grip and move the material around when buffing or polishing. 

This reduces heat build-up and also ensures even buffing and polishing. You can also dip the material in a can of cold water. Most buffing grinders include a cloth that wipes the fine particles as you work.

However, it is recommendable to use another cloth to clean the buffed surface manually. Bench grinders can also be used to polish metal and wood surfaces.

Polishing is slightly different from buffing, as it involves smoothening the top surface for an even finish. Polishing also improves the texture, allowing you to achieve a fine finish. 

You should move the material steadily towards the grinder for even application of the polish. Exercise precaution when working with wooden surfaces as they can easily catch fire. Also, avoid dipping wood in water. 

#5 Rust Removal And Shaping Objects

A bench grinder can remove rust, paint and other unwanted materials from the workpiece. Like grinding and sanding, the grindstone eats away the rust and other superficial build-ups that are formed on the surface.

When using a bench grinder to remove rust, you should set it a lower rpm to avoid overheating or grinding into the material. 

Avoid using water to cool off the material, since the increased humidity will only result in more rust.

Bench grinders are also useful when shaping objects. Use a gentle back and forth movements to shape the object evenly. You should also lock the workpiece in place for precision. 

A bench grinder can smoothen rough edges, create incisions required for bending the metal or buffing and polishing for a clean finish. You can dip the material in coolant to reduce overheating, but make sure you wipe away all moisture, especially if it is vulnerable to rusting.  

Final Words

You can find several other minor uses for a bench grinder, which is among the most useful power tools in any auto shop. The tool allows you to replace the grindstone, so you can work different materials and achieve various fabrications. 

However, not all offers you will encounter are desirable. It is still essential to review all the crucial aspects, including features and specs, brand and model reputation, functionality, power rating, recommended applications, maintenance, longevity and more. 

Make sure you purchase all your power tools from credible, reliable retailers that can guarantee top quality products from genuine manufacturers.

Checkout our top 20 bench grinder selection in 2020

Also, do let us know in the comment section if this article was helpful or where we should improve. Thank you!