Best bench grinder | Slow & variable speed

Bench grinders are power tools equipped with abrasive grinding wheels. Their primary function is to grind down various types of materials, typically wood or metal.

There are countless uses for bench grinders. Often used for sharpening tools like blades and drill bits, when a dedicated sharpener is not around , they are also effective for cleaning, buffing, or polishing surfaces.

In the hands of a skilled worker, bench grinders can even be used to fashion new tools from raw metal.

Apart from the bench grinder itself, there are some other tools and accessories you will need to have to perform a variety of tasks.

Most bench grinders come with tool rests, although you may have to purchase an aftermarket rest that provides more adjustment options.

Grinders typically come with grinder wheels as part of the set, but again, you might want to purchase wheels with different grit sizes depending on how you will use the grinder.

It is also a good idea to purchase a buffing wheel for honing blades and buffing wooden pieces.

Do you need a professional brand for DIY use?

In most of my tool reviews, I always emphasize the need for pro-level equipment, even for DIY use. Bench grinders are among the few exceptions to this rule. For most purposes, a good DIY brand will do just fine.

Bench grinders are fairly simple in terms of design and function, so even a DIY brand should provide satisfactory performance for a tool that’s not used often.

Whether you go for a pro or DIY model though, one thing that’s good about DIY brands is the variable speed setting.

Many inexpensive brands–and even most heavy-duty models–simply run at one speed, which limits your options considerably.

What’s it like to use a good-quality bench grinder?

Fast speeds aren’t usually an issue for heavy-duty jobs for which you will probably want your grinder going at full bore the entire time.

For most other applications, however, you will likely need to adjust the speed depending on the material you are grinding. In particular, you will want to set your grinder to slower speeds when sharpening chisels, to avoid overheating the metal.

Without a variable speed control, you will have to constantly turn the motor on and off to slow the wheel down. In addition to placing undue stress on the starter mechanism, this can get very annoying after a while.

Other than that, for commercial and industrial use, you will get a much better life span with a pro brand under daily use. And therefore you should consider if you want a slow or fast speed bench grinder.

For cutting metal, however, you should use a Dewalt chop saw for bulk cutting or pick the best cordless angle grinder for more portable metal cutting jobs.

The trouble of using a single-speed bench grinder

Most single-speed bench grinders only run at 3400 RPM, which is suitable for burr and stock removal.

But at that speed it can be a bit too fast for sharpening tools, ideally, a speed of about 1700 RPM is better.

Although tools and blades can still be sharpened effectively at high RPM, just more care needs to be taken with frequent stops to place the metal surfaces under heat in some water to cool down.

Without a variable speed control, you are pretty much limited to running your grinder at full bore all the time. You could turn off your grinder to slow it down of course, but this hinders work efficiency and quickly gets annoying. 

What sets variable-speed control apart from single-speed?

With variable speed control, you could run it at top speed when you need to remove stock and slow it down when sharpening tools.

Some people control the speed of their single-speed grinders with a rheostat or a dimmer circuit [1]. Although this will work with grinders that have brush-type motors, a grinder with an induction motor will burn up when operated in this manner.

Save yourself the trouble–and the expense–and simply get a variable-speed grinder if you are after out-of-the-box speed control.

With a single-speed high RPM bench grinder, there is more risk of overheating when sharpening tools, and you could ruin a perfectly good edge.

And if you are smoothing a workpiece, high speeds might leave burn marks on the surface.

On the other hand, all-pro made bench grinders like Dewalt, Makita, and Jet only come as a single-speed unit. 

Remember if a bench grinder is a brush-type motor you could use a rheostat or a dimmer circuit to control the speed on a pro-brand tool.

What DIYers should use?

Grinders intended for DIY home use usually have 6” disks. They typically run at speeds of 3400 to 3600 RPM and are suitable for most basic home improvement jobs.

Although they have smaller wheels than their 8” counterparts, many grinders with 6” wheels are surprisingly heavy.

Nevertheless, they are fairly easy to manage, and they are useful for even moderately difficult tasks.

What do professionals use?

Most pros use 8” grinders. They are better suited for heavy-duty work and are more appropriate for use with a buffing wheel or a wire brush.

Most 8” models do tend to run a bit slower than 6” grinders, but you won’t have to change the wheels as often, and they generally require much less maintenance.

In most cases, it would be better to go for an 8” wheel right off the bat.

Larger bench grinders are useful for basic sharpening of chisel blades and the like and metal-polishing tasks, and you will save money in the long run because you won’t have to keep changing the wheels.

If you do need the more acute curvature provided by a smaller wheel, you can simply swap out the standard 8” wheel for others that are better suited for the job you need to do.

You will definitely get more use out of an 8” grinder and a variety of wheels than you would with a 6” grinder and the same set of wheels.

The Dewalt bench grinder is the best value for money pro brand bench grinder, this is my recommendation if you want quality over variable speed.

The Craftsman 8” bench grinder has a speed control that varies the wheel rotation from 2000 to 3450 RPM, making it suitable for almost any grinding, sharpening, or buffing task.

It has a work light with a flexible arm so you can work even in low-light conditions.

You do have to choose the right wheels for this grinder, as it can wobble a bit with cheaper wheels.  But get some good quality wheels on it, and the performance is stable and reliable.

If you use a grinder mainly for DIY work and jobs that require you to have speed control like for sharpening your wood chisel set. The craftsman is best variable speed bench grinder.

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Or you could go for a slow speed bench grinder like the Makita GB602 bench grinder below this is a good pro-tool-choice for sharpening tool blades.

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You can use your bench grinder as an effective buffer or polisher simply by attaching a buffing wheel in place of the grinder.

Buffing wheels come in 6” and 8” diameters, so you should have no trouble finding a wheel that will fit your grinder.

For polishing wood or metal, you will want a wheel with a leather buffing surface. For polishing or smoothening plastic surfaces, you will need a cotton buffing wheel.

Grinding wheels come with different grit sizes, each suited for specific types of jobs.

Coarse grit ranging from 16 to 24 grit, medium grit wheels range from 36 to 60 grit, and fine grit wheels range from 80 to 120 grit.

There are also super-fine grit wheels that have grit sizes from 150 and higher.

The coarser the grit is, the better suited it is for removing stock and burrs.

For smoothening surfaces, go for a wheel with a finer grit size. Most grinding wheels have grit sizes ranging from 24 to 100.  

Grits also come in different colors, which indicate the type of material used. Like grit sizes, different colors are better suited for different purposes.

Most wheels for grinding are made of aluminum oxide and are typically gray or brown.

You may also come across silicon carbide wheels, which are usually black or green.

Ceramic wheels are usually blue or pink, or a combination of these two colors.

1. Always perform a safety check before using your grinder.

Make sure that the grinder is set securely on your workbench to reduce vibrations. The tool rest should also be set securely, with about 1/8” of space between the edge of the tool rest and the grinding wheel.

This space should be free of debris at all times, and you should have enough space to push the object to be sharpened back and forth.

2. Slow rotation can reduce overheating risks.

There is always a risk of overheating when using a bench grinder, due to the friction produced by the grinding wheel against the material.

You can generally avoid this by using a rough grit wheel and slow rotation speeds, although this isn’t always practical.

In any case, you should always have a container of water nearby.

So you can quickly dip your metal tool in if it starts to get too hot.

3. When sharpening chisels or other metal implements…

It might be better to have a container of pre-warmed fast-quench oil handy, which does a better job of preventing cracking than a can of water.

Keep a firm grip on whatever it is you are sharpening or buffing to prevent it from flying out of your hands when pushed against the wheel.

4. Keep your tool or workpiece centered on the wheel.

Keep it well away from the sides to prevent damaging the grinding wheel.

5. Use light pressure.

In general, you will want to apply light and even pressure when pressing your tool or workpiece against the grinding wheel.

Pressing too hard could remove too much material and increase the possibility of overheating.

As with all power tools, getting the most out of your bench grinder involves knowing what you will use it for and what the best features and accessories are for the job.

Get a good 8” grinder that can accommodate a variety of wheel types, and it should provide years of reliable service. If you need to use a portable grinder instead, have a look here.