Best Bench Grinders

Buying guide for best bench grinders

There’s no doubt that a good bench grinder is an indispensable tool in a pro shop. You may not think of it as a priority for the home workshop, but ask the people who have one and they will probably say they wouldn’t be without it. A variety of sizes and power outputs ensure there’s something for every user, from the hobby machinist or mechanic to the full-time professional engineer.

BestReviews is here to help you decide which of those options will best fit your needs. We can provide the information you need to make the right buying decision for your workshop.

As always, we’ve selected a top five. These are the models that receive our recommendation. Each one offers class-leading standards of performance and value.We’ve also compiled the following bench grinder shopping guide if you would like more details before you buy.

You should always bolt down your grinder. If you need to move it around, consider buying a purpose-built, heavy-duty stand, giving you mobility without sacrificing stability.

Why you need a bench grinder

A bench grinder is a surprisingly versatile tool. Grinding to shape pieces of metal is an obvious task. A grinder is often used for sharpening, too – everything from kitchen knives to lawn-mower blades. Change one of the grinding wheels for a wire wheel and it can remove rust or paint. There are also flap wheels for polishing and leather wheels for honing.

Visit your local engineer, auto shop, or hardware store and see how much they charge for relatively simple jobs – jobs you could do yourself if your workshop had a bench grinder.

Do the math and you’ll see how quickly it will pay for itself!

Bench grinder features to consider

A bench grinder is a fairly basic tool. It contains an electric motor that drives a pair of shafts. Each shaft is attached to a grinding wheel, with guards for safety and tool rests for easier control of the workpiece.

While all bench grinders have a similar design, there are variations in size, power, construction, and other features.

Size and power

The diameter of the grinding wheel determines the size of the bench grinder. In general, a bigger wheel has more mass, requiring more power to turn and maintain speed under load (most bench grinder wheels rotate between 3,400 and 3,600 rpm).

Budget bench grinders are often rated in amps, while more powerful models are rated in horsepower (ranging from about one-quarter to one horsepower). It’s important to note that all of these ratings are under “no load” conditions – the motor is running but not grinding anything. Grinding or sharpening slows the wheel a fraction. If the motor is strong enough, the drop in speed is barely noticeable. However, if there’s too little power, the wheel won’t cut efficiently. In rare cases, it could even stall. Therefore, more power is better.

• Six-inch bench grinder: Many people find that for general-purpose use, a six-inch grinder with a wheel width of either one-half inch or three-quarter inch is perfectly adequate for most jobs, such as sharpening tools and removing rust. We’d favor a one-half horsepower motor for a six-inch grinder, but we’d consider one-third horsepower a basic minimum for light-duty home workshop use.

• Eight-inch bench grinder: There are benefits to having the larger eight-inch wheel, which is usually one inch wide. It provides more cutting area, so the material you’re grinding is removed more quickly. If you’re sharpening tools, you can work on more of the blade at once, so it’s easier to get an even edge.
  Eight-inch grinders need more power to rotate at the same speed (there’s increased mass to move), so here we prefer to see a three-quarter horsepower or greater motor. The best professional-grade bench grinders deliver one horsepower.

• Slow-speed bench grinder: This is the exception to the general 3,400 to 3,600 rpm rule. These machines are mostly marketed to woodworkers. Woodturning and carving chisels can be damaged by the high temperatures created by ordinary grinders, so they have lower speeds of 1,725 rpm. Most of these are eight-inch models, but because they run more slowly, a one-half horsepower motor is fine.

• Variable-speed bench grinder: There are a few bench grinders on the market that offer variable speed. Not surprisingly, these are a little more expensive than their single-speed counterparts. If you spend equal amounts of time working with wood and metal, one of these could be a good investment. Most people are focused on one or the other, so one speed is usually all you need.

Construction

Substantial construction gives a bench grinder the rigidity you need to do accurate work. Grinding is usually quite a loud task, but a heavy-duty build helps to dampen the vibration and so reduce noise levels.

• Steel is solid and durable.

• Cast iron is even better, and it’s what you’ll find on high-quality machines, though it does cost more.

Additional features

• Guards: It goes without saying that guards are vital. On some bench grinders, a spark guard and eye shield are separate; on others, they’re combined. As long as they’re easy to adjust, the type you choose isn’t important.

• Tool rests: These should always be fitted. These can be set for particular grind angles and make it easier to control the workpiece.

• Lights: It’s important to see what you’re doing. Some bench grinders have small LED lights directly above the grinding wheels, others have a lamp on a flexible stalk.

• Feet: Rubber feet help dampen vibration and reduce noise.

Bench grinder prices

Bench grinders vary in price from $40 to $300 and more. There’s so much choice, it’s really a question of deciding on the specifications you need and shopping around for the right price.

• Inexpensive

At the budget end of the market, you’ll find perfectly good six-inch bench grinders for as little as $40 or $50, and up to about $100. These are ideal for occasional light-duty work, and you’ll recover your costs in no time.

• Mid-range

If you grind or sharpen on a regular basis, you’ll want to invest in higher performance – either a more powerful six-inch grinder or an eight-inch machine. A professional-quality bench grinder from a respected brand will cost anywhere from $100 to $300.

• Expensive

The very best tools can cost $300 and more. For that kind of money, you’ll get a powerful, robust, and dependable bench grinder that will last a lifetime.

Tips

• Always bolt down your bench grinder. Even applying light pressure against the grinding wheel will cause the grinder to move. That not only leads to inaccuracies but it’s also potentially dangerous. A fixed bench grinder provides a stable work environment. And because the vibration is dampened, it’s also quieter.

• Always work with the guards in place. And always wear eye protection.

• Work with caution. A rapidly rotating bench grinder creates substantial forces. Make sure you have a good grip on the workpiece, and approach with caution. There’s no benefit to forcing things – you’ll do more harm than good. Let the grinding wheel do the work.

• Keep the workpiece in motion, and work in short bursts. Bench grinders can transfer considerable heat to the metal you’re grinding or sharpening. Stopping often gives you a chance to check your progress and, equally importantly, reduces the chances that you’ll burn your fingers!

• Never work with a grinding wheel that’s chipped, cracked, or wobbling erratically. It could shatter at high speed, firing razor sharp fragments in all directions.

• Let the grinder reach full speed before starting work. That’s when the tool is cutting most efficiently. Never use the workpiece or a piece of scrap to slow down the machine when you’ve finished. You could damage the wheel.

• Make sure the area around the bench grinder is free of clutter. Any bits and pieces that might get caught in the wheel could suddenly turn into a lethal missile.

Leave plenty of space around your bench grinder so you can manipulate workpieces without bumping into things.

FAQ

Q. What do grit numbers mean on grinding wheels?

A. The grit number tells you how coarse the wheel is. Most bench grinders come with two wheels.

• A 36-grit wheel is designed for rapid material removal.

• A 60-grit wheel is for general-purpose shaping and sharpening.

• A 100-grit wheel is for fine sharpening.

• A 150-grit and higher wheel is for polishing.
   

Grinding wheels come in different materials, too. Standard wheels are often aluminium oxide or silicon carbide. White wheels, a type of aluminium oxide, are usually used on slow-speed bench grinders. Diamond wheels are used for sharpening very hard materials, such as cutting tools with carbide tips.

Q. Why are the guards and tool rests adjustable?

A: As you use your bench grinder, the grinding wheel wears away. If you don’t adjust the spark guards and eye shields, you could find yourself showered in tiny red-hot particles! Adjusting the tool rests helps maintain optimum performance. If the gap between the wheel and tool rest gets to big, you get excess vibration, and the wheel won’t cut as well as it should. There’s also the chance of the workpiece snagging on the wheel and getting pulled downward, which is very dangerous. The manufacturer’s instructions will tell you what the gap ought to be. Adjustments should be made regularly.

Q. I notice some people keep a jar of water by the grinder. Why?

A. Heat builds up rapidly in the metal you’re grinding, so cooling it occasionally lets you work longer. It’s also useful when sharpening cutting tools like chisels, which are heat-treated (tempered) when they’re made. If they get too hot, you could remove the temper, and they could go blunt very quickly. Dipping the tools in water reduces the chances of this happening.