Can You Slow Down a Bench Grinder. Slow speed bench grinder
Can You Slow Down a Bench Grinder?
Bench grinders are fantastic tools. The latest and most expensive bench grinders come with variable speed settings. But perhaps like me, you have an older model and would like to be able to lower the speed on your existing bench grinder, so that you can sharpen the blades of your tool collection more precisely.
How do you slow down a bench grinder? There are several effective ways of reducing the speed on a bench grinder, for example: controlling the router speed, fitting a belt pulley, using a variable frequency drive, reducing the wheel size and even building your own slow speed grinder.
In this article, I will discuss each of these different methods of slowing down your bench grinder and then you can decide which is the most suitable for your purposes.
Bench Grinder Speed
A bench grinder is a tool which spins grindstones, and these grindstones gently shape metal. They can quickly sharpen blunt tools. Most bench grinders run at about 3,450 rpm, although there are more and more variable speed grinders on the market these days.
If you’re careful and keep the wheel dressed. a high speed grinder will work fine for you. However, for sharpening blades, a low-speed grinder running at 1,750 rpm is a much better choice. A lower speed reduces the chance of the edge of your tool overheating.
Slow Speed Bench Grinders
Slow speed grinders do still generate heat, but it happens at a more controllable pace that is ideal for work on delicate metals. This is what is required for sharpening work because the edges of cutting tools are very thin and can overheat easily. With a slow speed grinder and some practice you can learn to sharpen just about any cutting tool without ruining the hardness of the blades.
Slow speed grinders tend to cost a bit more because they need better motors. Slow motors need to have more power and torque to overcome lower inertia and possible stalling during the grinding process. If you have a grinder already and don’t wish to make an expensive purchase, you can rest assured that there are many ways of slowing down your existing grinder.
Slowing Down Your Bench Grinder
There are many ways to slow down your bench grinder, these include: Router Speed Control Fitting a belt Pulley Using a Variable Frequency DriveI will discuss each of these methods of slowing down your bench grinder.
Router Speed Control
If the motor on your bench grinder is under 1HP you should be able to control the speed with a router speed control. My experience with this kind of set-up,however, is that when the speed is lowered, it loses its steady rhythm and jerks between 90 and 110 RPM
Fitting a Belt Pulley
You can slow down your bench grinder by fitting a belt pulley in the place of the wheel. You can then fir a V belt to a secondary shaft with a larger pulley wheel. The gear ratio would then be: diameter small pulley/diameter large pulley.
Using a Variable Frequency Drive (VFD)
By running the motor through a variable rheostat control, you will reducing the voltage to the motor. In order to make up for the reduced voltage, the motor will demand more amps. This will cause the motor to run hotter.
The correct way to do this is with a VFD (variable frequency drive). This will change the 60 cycle frequency that the motor runs on and make the motor a variable speed motor without changing the voltage or the amperage. There are plenty of VFDs available which convert 120V 1 phase to 220V 3 phase.
The down side of this is that when you slow it down with a VFD, the motor loses torque at the same time. This means that the grinder is easier to stall. VFDs aren’t as expensive as they used to be, but probably more than you want to spend on a low end bench grinder. This is the safest and most reliable way of slowing down your bench grinder.
Reducing wheel size to slow down grinder speed
Generally speaking, the smaller the wheel size, the slower the grinder speed. So as your grinding wheel wears down, it will also slow down. The thickness of the wheels is also significant. Thicker wheels last longer and cut more slowly generating more friction and heat. The downside of this. Is that the thicker discs often result in the workpiece becoming discoloured.
DIY Slow Speed Grinder
To make a slow speed grinder, you will need a mandrel. A mandrel consists of a basic shaft, which is threaded on both end to make arbors, two pillow block bearings, and a pulley.
I used a second pulley of the same diameter for the motor itself, making the grinding wheel RPM 1725 too. I mounted two 6″ X 1-1/2″ aluminum-oxide grinding wheels to the arbors and now I have a slow speed grinder that I made myself.
Bench Grinder Safety
It is important to remember that whenever you use a bench grinders, or any domestic tools, great care is required. Bench Grinders are powerful motorized spinning tools which should always be used exactly as directed by the manufacturer.
The user should make sure that they have taken great care to read the instructions before setting up and using the bench grinder. It is also important that the user takes care to wear appropriate safety gear including: hats, gloves, eye protection, hearing protection and spark resistant clothing.
You might have decided that a grinders a great asset to your tool shed, if this is the case, it is worth investing in a grinder that can work at a slower speed. If you already have a grinder that only works at higher speeds, there are a number of ways of slowing the speed.
The most successful of these methods is to use a variable frequency drive which will reduce the voltage and force the grinder to work at a much slower speed.
RIKON Power Tools 80-805 8″ Slow Speed Bench Grinder Review
If you do lots of tinkering at home, then your tools are bound to get dull eventually, regardless whether you used them correctly and took proper care of them. The edges of chisels, knives, and blades will get blunt with lots of use, so how do you regain their sharpness?
It is the duty of the bench grinder to tackle all that sharpening and honing. The bench grinder specializes in those procedures and more. Corrosion is also something we see on tools and the bench grinder can take care of this issue as well.
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If you are on the hunt for a good bench grinder, you can start by reading reviews on the precision tools site about the different products out there. Check out our review of the RIKON Power Tools 80-805 8-inch Bench Grinder.
There are some factors you need to mull over first before buying a bench grinder. You have to consider where you are going to use the item since this particular power tool has lots of applications—it can be used to sharpen cutting devices, even out mower blades, and adjust faulty parts that require resizing. It can also recondition corroded parts. The RIKON Power Tools 80-805 is intended to be used as a sharpening device for your cutting tools and as wheel maintenance too.
One of the main parts of a bench grinder is the wheel. It is primarily used for grinding on varying tasks. It is important that you take into account the kind of wheel the grinder has and it should be something that will work for your planned projects or tasks that you frequently do. For instance, you can opt for a model like the 80-805 if you do lots of sharpening and smoothing.
Furthermore, you have to factor in the size of the motor too, plus the measurement of the wheel. Bigger motors mean bigger grinding power, so if you want to tackle more heavy-duty tasks you can opt for a model that comes with a sizable motor. As for wheels, this model is the 8-inch slow speed type so this means it is sufficient enough for home workshops and a good deal of tasks.
The 80-805 operates well and while it does produce a bit of vibration, it does not do the whole thing too badly. It can perform what it is supposed to accomplish. It was also pretty easy to set up; all you need to do is get the item out of its box, add some tiny bits to complete the unit, and you are good to go.
It has decent balance overall. As you switch the unit off, the wheel will continue to spin for a few minutes before it finally stops. Overall, this is a good, well-constructed unit. It comes with a diamond dresses plus friable wheels, but it is encumbered by some major disadvantages, which we are going to discuss next.
The issue with the RIKON Power Tools 80-805 is that its grinding wheel is positioned in place by a stamped disk instead of the machine type. This disk often lies against the motor shaft’s shoulder cut to sustain a straighter wheel. However, this shoulder is a bit short for such a bigger disk to rest against, so it ends up only pressing on the hole’s edge in the disk and does not give lots of metal/metal contact that can act as support for the disk.
The tool rests were also a bother to adjust and are not that sturdy, but at least there are options when it comes to aftermarket replacements.
You can also choose to make your own, but if you do not want to be bothered, just go for another bench grinder model with all the features and the design elements you need. Another issue about the product is that both wheels, unfortunately, produce a lot of radial and lateral wobble.
This radial wobble can be solved by dressing the wheels, but the lateral wobble is going to be a persistent problem. As mentioned earlier, this unit does produce vibration and this vibration takes place whenever the grinder’s speed comes out and it stabilizes.
How to convert single speed grinder or drill to variable speed
The RIKON Power Tools 80-805 8-inch Bench Grinder is a well-made product, but it displayed lots of drawbacks in terms of design. This design problem could have been solved but it appears the company did not try to do anything with those issues. It can still be improved on though. Just get another bench grinder instead from other brands.
Slow speed bench grinder
The Rikon 80-805 Slow Speed Bench Grinder with 8″ wheel offers heavy duty grinding due to its 8″ diameter and 1″ width wheel. The Rikon 80-805 bench grinder is modeled with a smooth-start 1/2 HP motor operating at a no load speed of 1,750 RPM. The slow speed and large width make this grinder ideal for sharpening operations (among other uses). The combination of an 8-inch diameter wheel and slow grinding speed reduces heat build-up and minimizes the possibility of “bluing”, especially when you’re sharpening chisels and other tools.
The Rikon 80-805 Slow Speed Bench Grinder comes with two 1″ x 8″ white aluminum oxide grinding wheels. One wheel is 120-grit, and the other wheel is a much coarser 60-grit composition. It also comes with a diamond wheel dresser for use to true the grinding wheels before using or starting your next grinding operation. The Rikon slow speed bench grinder is equipped with a cast iron base that features anti-vibration rubber feet and mounting holes for convenient attachment to a workbench or grinder stand.
In addition, the Rikon 80-805 Slow Speed Bench Grinder features a polycarbonate eye shields that can be adjusted to stay put but can still be easily moved by hand. The 80-805 bench grinder comes with tool rests, eye shields, spark arrestors, a 6 ft. power cord, and 5-year warranty. Also available is the optional Rikon bench grinder stand 80-910.
Also, the bench grinder has sealed lubricated bearings in the motor housing that do not require any additional lubrication from the operator.
Rikon 80-805 Slow Speed Bench Grinder Key Features
Rikon 80-805 Slow Speed Bench Grinder Specifications
- Horsepower: 1/2HP
- Amps: 3A
- Volts: 120V, 60Hz
- Speed: 1750 RPM
- Wheel diameter: 8 in.
- Wheel grits: 60 and 120
- Length: 16-3/8 in.
- Width 10-3/4 in.
- Height: 11-1/4 in.
- Base (L x W): 7-5/8 x 5-1/2 in.
- Net Weight: 34.2 lbs
- Optional bench grinder stand (Rikon 80-910): 69.99
- Warranty: 5 year limited
- Price: 99.99
David C. Smith
DCS spends most of his time watching Mythbusters, trying to figure out what the labels that they blur out say, so that he can recreate the explosions. His hobbies include impersonating Chuck Norris doing an impersonation of Sean Connery and fly fishing. David does his own stunts.
The 10 Best Bench Grinders of 2023
Michelle Ullman is a home decor expert and product reviewer for home and garden products. She has been writing about home decor for over 10 years for publications like BobVila.com and Better Homes Gardens, among others.
Johnathan C. Brewer II is a licensed general contractor specializing in kitchen, bath remodels, and general construction with two decades of professional experience.
Emily Estep is a plant biologist and journalist who has worked for a variety of online news and media outlets, writing about and editing topics including environmental science and houseplants.
If you work with metal, including auto repair, owning a bench grinder—which smooths and shapes rough edges, polishes and sharpens metal, and removes rust, paint, and other finishes—may be worth your while.
Deane Biermeier, a licensed carpenter and contractor, as well as a member of The Spruce’s Home Improvement Review Board, says, “Bench grinders are surprisingly versatile tools. Once you own one, you’ll wonder how you made it this far without it. However, most DIYers don’t need to spend a fortune on a bench grinder for it to be useful. Unless you depend on the tool to make a living, most homeowners won’t require one that’s larger than 1/2 to 3/4 horsepower. The secret that makes bench grinders so useful is the numerous and varied types of wheels and attachments available.”
We evaluated bench grinders based on power, versatility, reliability, construction quality, and overall performance.
DeWALT DW756 6-Inch Bench Grinder
The reasonable price and superior construction make this tool our best overall pick. The DeWALT DW756 6-Inch Bench Grinder is a great option for amateur handypeople as well as tradespeople who need a machine that can do some heavy lifting. Available in the classic DeWALT yellow, this grinder will look great on just about anyone’s tool bench. It has pre-drilled holes, so you can easily mount it to your bench to reduce vibrations. Use this versatile bench grinder to smooth down metal edges, sharpen lawnmower blades, grind away rust or grime from auto parts, sharpen knives and chisels, or even smooth or buff wood.
The DeWALT DW756 grinder is easy to use and reasonably quiet. This 15-inch long machine sports a 5/8-horsepower motor, which is quite a bit in this small body. It can run up to 3,450 rpm for high-speed needs. The motor housing and base are made of industrial cast iron, while the tool rests are aluminum. There’s 12.5 inches between the wheels for a less-cluttered feel, and the wheels have exhaust ports in the rear of their guards to prevent overheating. This grinder comes with eye shields, spark deflectors, and 36- and 60-grit grinding wheels. The whole thing weighs just over 28 pounds and includes a three-year warranty.
Price at time of publish: 100
Wheel Size: 6 inch | Power: ⅝ horsepower | Max. RPMs: 3,450 | Included Wheels: 36-grit, 60-grit | Worklight: No
WEN 4276 6-Inch Bench Grinder
Popular, simple, and inexpensive, the WEN 4276 6-Inch Bench Grinder is a great value pick. The WEN grinder is an ideal high-speed option for anyone who is looking for a quiet and compact bench grinder than can get the work done. It sports a 2.1 amp motor for a maximum speed of 3,450 rpm. It can fit grinding wheels that are 6 inches in diameter and 3/4 inch wide. It has extra-large eye shield and major wheel guards for added safety and worry-free use.
The WEN 4276 comes with both a 60-grit and 36-grit grinding wheel for general purpose and faster grinding, but it can be outfitted with a variety of wheels. It also sports a flexible worklight for convenient and precision work at any time. The machine is easy to mount with a wide and sturdy base, and WEN sells an optional cast iron stand for non-bench usage. This is a great choice for anyone who just needs a bench grinder occasionally for simple tasks like sharpening knives and tools, smoothing rough edges on metal or wood, or cleaning away rust or paint from metal items.
Price at time of publish: 75
Wheel Size: 6 inch | Power: 2.1 amp | Max. RPMs: 3,450 | Included Wheels: 36-grit, 60-grit | Worklight: Yes
Best for Sharpening Blades
WEN BG4270T 10-Inch Wet/Dry Sharpening System
Keep knives, axes, chisels, woodcarving tools, scissors, screwdrivers, and any other object that needs to have a clean and sharp edge in perfect condition with this highly effective sharpening system from WEN. The tool has a 10-inch, 220-grit wet sharpening stone on one side and an 8-inch by 1 1/8-inch leather stropping wheel on the other. The 1.6-amp motor keeps things spinning at a maximum of 115 rpm, which is speedy enough to get the job done with good control. You can reverse the direction of the spin with a flick of the switch as well, which can make various sharpening tasks easier.
The sharpening system comes with an angle guide, honing compound, water reservoir, and jig for sharpening chisels and planer blades. It has a handle for transport, or it can be mounted to your benchtop. You can also use the sharpening system with many other accessories from WEN, including their sharpening kit.
Price at time of publish: 141
Wheel Size: 10 inch | Power: 1.6 amps | Max. RPMs: 115 | Included Wheels: 220-grit, leather | Worklight: No
Jet 578008 8-Inch Industrial Bench Grinder
The Jet 578008 8-Inch Industrial Bench Grinder offers one full horsepower for your grinding needs; that’s a lot of power. This grinder sports a heavy-duty motor and is CSA and CUS certified. It is ideal for small business owners, contractors, construction use, and tradesmen keeping their tools in sharp shape, as well as those who do auto repair or other metalwork. While more than what the average DIYer requires, this is worth a look if you need a bench grinder for heavy-duty tasks.
This 44-pound electric bench grinder functions at 3,600 rpm for real speed. It is set up with 115-volt, 11-amp, 60-hertz service but comes with a guide for rewiring for 5.5-amp 230-volt use. This machine is powerful enough for professional needs and durable enough for a professional setting, with full wheel dressings, a single dust chute, large sealed bearings, and adjustable safety shields. It also has a toggle switch safety key for added protection. This 8-inch grinder comes with one fine and one coarse grinding wheel.
Price at time of publish: 469
Wheel Size: 8 inch | Power: 1 horsepower | Max. RPMs: 3,600 | Included Wheels: 36-grit, 60-grit | Worklight: No
Best Combo Tool
Bucktool Combo Belt Sander/Bench Grinder
Combine a bench grinder and a belt sander, and you get this versatile tool from Bucktool Combo. It has a 1/3-horsepower motor, which gives it plenty of muscle for typical grinding/sanding tasks, such as sharpening blades, smoothing out metal or wood, or buffing away rust or paint. With a 6-inch, 60-grit grinding wheel on one side and a 2-inch by 42-inch sanding belt that can be used in either a vertical or horizontal position on the other, this is a great two-in-one addition to your workshop. There are a LED light and an eye guard over the grinding wheel, which spins at 3,450 rpm. The sanding belt has a top speed of 4,480 feet-per-minute and comes with two small work platforms: one cast iron for working with metal, and one aluminum for working on wood.
The base of the tool is cast iron with rubber feet to help reduce vibrations. All in all, while not a tool for a professional, if you’re in the market for essential tools for DIY jobs, this is a worthwhile investment.
Price at time of publish: 276
Wheel Size: 6 inch | Power: 1/3 horsepower | Max. RPMs: 3,450 | Included Wheels: 60-grit wheel, sanding belt | Worklight: Yes
Best for Crafters
Central Machinery 3-Inch Bench Grinder with Flex Shaft
Some people, especially crafters, need a bench grinder not to tackle large tools or pieces of metal, but to polish, grind, or clean small items, such as metal jewelry, trim, or small hand tools. For those users, the Central Machinery 3-Inch Bench Grinder with Flex Shaft fits the bill.
This mini bench grinder has a 31-inch flexible shaft that accepts a variety of attachments—including most Dremel attachments—for use in grinding, polishing, deburring, cleaning, and sanding metal, including nuts and bolts, small automotive parts, jewelry, knives, small gardening tools, and other detailed metalwork.
Although small, this bench grinder has a reasonable amount of power, and variable speed control up to a whopping 10,000 rpm. It includes a 3-inch grinder stone and a 1/8-inch shaft-mount grinder stone. It’s a great addition to any crafter’s or metalworker’s workshop.
Price at time of publish: 64
Wheel Size: 3 inch | Power: 1.3 amps | Max. RPMs: 10,000 | Included Wheels: Grinding wheel, flex shaft with grinding stone | Worklight: No
Powertec BF600 6-Inch Bench Buffer
If your hobby, job, or household tasks require you to do a lot of buffing or polishing of metal, then adding the Powertec BF600 6-Inch Bench Buffer to your workshop will make your life easier. This powerful tool isn’t for grinding down metal, but rather for smoothing, polishing, or buffing various materials, including aluminum and chrome and also plastics or even wood. You can use it to polish silver or copper, get jewelry sparkling, buff up serving pieces, or sharpen blades, just for a start. It has a 1/2-horsepower motor that keeps the two 6-inch wheels spinning at 3,450 rpm. The cast iron base keeps the tool steady, so excessive vibration won’t be a problem.
The tool includes two 6-inch cotton buffing wheels, one soft and one firm. While not as powerful as some other grinders, it definitely has enough oomph to quickly polish or buff away grunge, rust, and other undesirable coatings to bring back the shine and sparkle to your metal, plastic, or wooden items. It’s reasonably quiet, as well.
Price at time of publish: 89
Wheel Size: 6 inch | Power: 1.5 HP | Max. RPMs: 3,450 | Included Wheels: soft and firm buffing wheels | Worklight: No
Best for DIYers
Skil BI9502-00 8-Inch Benchtop Grinder
If you are a DIY metalworker, or just like to sharpen your own blades and keep your tools in good condition, then you’ll appreciate the Skil BI9502-00 8-Inch Benchtop Grinder. It can handle just about any typical DIY task, including smoothing down welds and rivets, removing rust from gardening tools, sharpening your knives, or bringing a chisel back to life. The tool has a powerful 3-amp motor with 3,450 rpm. The tool rests are adjustable, so you can position whatever you’re working on just how you need it. The base of the grinder is pre-drilled to make it easy to mount on your workbench; this helps prevent vibrations.
Two 8-inch wheels are included: one coarse and one medium, so you can tackle a wide variety of materials. There’s a built-in work light positioned over each wheel, which makes it easy to see your progress as you work, whether you’re sharpening a blade, polishing metal, or honing a knife. There’s even a built-in water-cooling tray to prevent excess heat and friction.
Price at time of publish: 149
Wheel Size: 8 inch | Power: 3 amps | Max. RPMs: 3,450 | Included Wheels: 36-grit, 60-grit | Worklight: Yes
Best Slow Speed
WEN 4286 8-Inch Slow Speed Bench Grinder
While higher speeds are perfect for grinding and deburring, a bench grinder with a lower speed is best suited to sharpening. So if your main needs are keeping knives, scissors, gardening tools, and other bladed devices honed and ready to cut, the WEN 4286 8-Inch Slow Speed Bench Grinder is a great choice.
The tool has plenty of power, with a whisper-quiet 3-amp motor. Top speed is 1,750 rpm, which gives you much more control than is typically found with faster bench grinders. Eye guards are mounted over each of the 8-inch wheels, but as with any power tool—and especially a tool that creates a lot of fine, flying dust and particles, such as a bench grinder—additional eye protection is mandatory.
This WEN bench grinder includes two 8 x 1-inch wheels: one fine 120-grit for detail work, and one medium 60-grit for general buffing, sanding, and polishing.
Price at time of publish: 142
Wheel Size: 8 inch | Power: 3.0 amps | Max. RPMs: 1,750 | Included Wheels: 120-grit, 60-grit wheel | Worklight: No
Best Variable Speed
Delta Power Tools 23-197 8-Inch Variable Speed Bench Grinder
Most bench grinders have just one maximum speed, but a variable speed bench grinder offers you more control; go with the slow speed for careful sharpening of axes, gardening tools, knives, and other bladed tools, or speed it up to deburr, polish, grind, or clean your various tools or other metal objects.
The Delta Power Tools 23-197 8-Inch Variable Speed Bench Grinder gives you the control you need and the features you want. The 5-amp motor lets you choose variable speeds from 2,000 to 3,400 rpm. The two tool rests are independently adjustable, and the left tool rest has a drill bit rest so you can get the perfect angle every time. There’s even a removable water tray, so you can easily keep whatever metal object you are working on from overheating due to friction. Plus, this bench grinder has an adjustable work light to help you FOCUS on your task.
You get two 8-inch grinding wheels: one 36-grit and one 60-grit, so you can choose the appropriate wheel for your needs.
Price at time of publish: 227
Wheel Size: 8 inch | Power: 5.0 amps | Max. RPMs: 3,400 | Included Wheels: 36-grit, 60-grit wheel | Worklight: Yes
Easy to use, a compact size, and 5/8-HP that provides effective high-speed grinding: that’s why the DeWALT DW756 6-Inch Bench Grinder wins our top spot for a tool suited to both the beginner or more experienced DIYer. But if you need professional-level power, you’ll appreciate the full 1-HP provided by the Jet 578008, which is durable and versatile enough for use in a commercial shop or at home.
What to Look for in a Bench Grinder
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 they are excellent for sharpening knives and tools, grinding away rust, paint, or grime, 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.
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.
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 1/4-horsepower. Most 8-inch grinders have around 5 amps of power, which is roughly 3/4 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.
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, model-building, or reviving rusted metal items.
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.
While grinding, shaping, and buffing metal are the primary uses of a bench grinder, you absolutely can 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.
Yes. Most bench grinders come with multiple wheels that correspond to different tasks. Take time to consider the task at hand, and select the correct wheel for the job.
Why Trust The Spruce?
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. Deane Biermeier, a licensed carpenter and contractor as well as a member of The Spruce’s Home Improvement Review Board, provided further information.
A bench grinder is probably not a tool you’ll use every day. However, if it’s available and set up correctly, you’ll be surprised how often it comes in handy for everything from sharpening tools to rounding over thread ends on a cutoff bolt. We’ve assembled these tips to help you get the most out of your grinder.
Keep a Container of Water Handy
Most chisels and other cutting tools are made of tempered steel. If the steel gets too hot and turns bluish black, it’s overheated and won’t hold an edge very long. To avoid ruining the edge of a tool by overheating, keep water nearby to cool the tool. A good technique is to move the tool once across the bench grinder for no more than a few seconds. Then dip it in the water. If the steel edge does overheat and turns color, grind the edge back to good steel and start over.
Bucktool new low speed bench grinder!
Grind Small Objects Safely
Hold small objects with locking pliers. This keeps your fingers a safe distance from the grinding wheel and protects them against burns from the hot metal. It also gives you better control over the grinding process.
Make Tool Sharpening Guides
Here’s a better way to hold tools securely while you’re grinding them—and take the guesswork out of creating the right bevel angle. It’s a short piece of 2×4 with an angled end and a 1-1/4-in. hole for a clamp. I made one for sharpening chisels and plane blades, and a few more with different angles for wood-turning tools. Large labels with the tool’s name tell you which blocks are for which tools. For a Delta grinder with a 6-in.-diameter wheel, a 5-1/2-in.-long piece of 2×4 aligns the tool to the wheel just right. For other bench grinders, you may need to adjust this length. Note: The angle you cut on the block is not the same as the tool’s bevel angle. But let’s skip the math. To determine the block angle, turn off the grinder and hold the tool’s bevel flush against the wheel. The angle of the tool shaft to the workbench is the angle to cut on the 2×4. Our thanks to Ray Caputo for this sharp accessory.
Consider a Low-Speed Grinder for Sharpening
Unless they’re variable speed, most bench grinders run at about 3,450 rpm. If you’re careful and keep the wheel dressed (more on that in another tip), these high-speed grinders work fine. But for sharpening garden and other tools, a low-speed grinder running at 1,750 rpm is a better choice. The lower speed reduces the chance you’ll overheat the edge of your tool. Another advantage of a low-speed grinder (100 to 150) is that this type typically includes friable white grinder wheels, which do a better job of sharpening than the gray grinder wheels usually included with high-speed grinders. See how to use an angle grinder.
Dress Wheels Frequently
Wheel dressing squares the face of the wheel, but more important, it exposes new grit for more efficient cutting. As a wheel is used, the spaces between the cutting grit can become clogged, and the grit itself dulled. A wheel in this condition can cause overheating and slows material removal. A wheel dresser like the one shown here (15 to 30) has a bar with diamond grit impregnated in it. Holding the bar against the spinning wheel cuts away the surface to expose new grit, squares the face of the wheel and rounds the wheel. To use a dressing tool like this, start the bench grinder and wait for it to reach full speed. Then press the diamond wheel dresser against the spinning wheel, holding it perpendicular to the face of the wheel. Be sure to wear a good-quality dust mask. The fine aluminum oxide dust is very bad for your lungs. Draw a pencil line on the wheel before you start to help you gauge when you’ve removed enough material from the wheel. Dress the wheel just until the pencil line disappears.
Watch for the Sparks to Come Over the Top
When you’re sharpening a chisel or other tool, you can tell when the edge is getting sharp by watching the sparks. When the edge is blunt, the sparks are deflected downward. But as the edge gets sharper, the sparks roll over the tool and cascade down the surface facing you. When you see this start to happen, be careful about grinding much more because a thin edge is very vulnerable to overheating.
Make an Angle Gauge
Chisels and other cutting tools work best if their edges are ground at the correct angle. You can search online to find the optimal angle for whatever tool you’re sharpening. Most wood chisels should be ground to about a 25-degree angle with a secondary micro-bevel angle of 30 degrees on the tip of the blade. An angle gauge allows you to set the tool rest at the desired angle. You can make an angle gauge from a thin piece of cardboard using an inexpensive protractor. 1. MARK THE ANGLE ON CARDBOARD Align the center mark on the protractor with the top edge of the cardboard. Then turn the protractor until the desired angle is also aligned with the top edge. Draw a line along the protractor to mark the angle. Don’t forget to label the angle. Cut along the line to create the gauge. 2. ADJUST THE TOOL REST Set the cardboard on the tool rest and adjust the angle of the tool rest until the wheel contacts the center of the angled portion of the cardboard gauge.
Upgrade the Tool Rest
Inexpensive bench grinders have tool rests that are finicky and difficult to adjust. If you do a lot of tool sharpening or simply want a bench grinder tool rest that’s easier to adjust, consider adding a stand-alone tool rest. There are several variations, some made for specific tasks like sharpening lathe turning tools. This Veritas model has two adjustments for positioning and aligning the tool rest, and levers for easy tightening. You can also buy an attachment that holds chisels or plane irons.
Make Your Grinder Portable
Even the most nicely organized home workshops don’t have enough bench space to devote a section to a bench grinder. A good solution is to mount your grinder to a board or small stand so you can clamp it to the bench when you need it, and store on the shelf when you don’t. The compartment on this grinder stand is a good spot to keep your dressing tool and safety glasses so they’re handy when you need them. For a fancier version, build a little drawer to fit the space under the grinder. The stand is built from two 12 x 16-in. pieces of 3/4-in. plywood separated by two 4 x 12-in. uprights. We used two 5/16-in. bolts with washers and nuts to attach the grinder, leaving enough space in front of the grinder to mount a stand-alone tool rest.
Easy-to-Clamp Mobile Base
Shazam! Fasten your bench-top tools to your workbench in seconds. Bolt 3/4-in. plywood bases on the tools and then glue and screw a wood strip along the front edge to fit into a woodworking vise. Crank this strip into a vise to lock the tool into place. If you don’t have a vise, drill a couple of clearance holes along the face of the wood strip on the base and drive screws through the strip into the edge of your workbench. Then just unscrew to remove the tool.
Set Up a Polishing Station
A bench grinder fitted with a wire wheel on one side and a cotton buffing wheel on the other side, or buffing wheels on both sides, makes a great cleaning and polishing tool. You’ll also need a set of polishing compound sticks (14). Polishing compound sticks are color coded to indicate the grit, from coarse to very fine. To use the polishing wheel, hold the stick against the buffing wheel as it spins to transfer some polishing compound to the wheel. Then hold the object lightly against the wheel and let the compound polish the surface.
Sharpen Your Lawn Mower Blade
Sharpening your lawn mower blade is easy with a bench grinder. Grind the tapered cutting edges with a grinder only if you see nicks in the blade. Follow the factory angle of the cutting edge. The grinder will remove nicks in the blade much faster than you can file them.
Not All Grinding Wheels are the Same
You can use two kinds of aluminum-oxide wheels to sharpen your chisels; one is blue-gray and the other white. We used the darker-color wheel, which is harder and will keep its shape longer. The drawback, however, is that it grinds hotter than the softer, white wheel. Too much heat will weaken the steel. The soft wheel will need more frequent shaping with a dressing tool, but you’ll be less likely to burn the edge of your chisel while grinding. For best results, use a 100-grit wheel to shape your chisel blades.
Know When to Replace a Wheel
Slide the wheel over your finger and tap the wheel in four places with a screwdriver handle. All taps should sound the same. If they don’t, scrap the wheel. It’s cracked.