Selecting the right grinding wheel for your project is important and with an almost incomprehensible array of products to choose from, it can present a challenge. That’s why we have put together this definitive overview to guide you into making the most informed choice possible.
What is a grinding wheel?
A grinding wheel is a precision tool with thousands of cutting points on its surface. abrasive grains that are held in place by a bond matrix (hence these are known as bonded abrasives) and separated by pores.
These pores are hollow spaces between abrasive grains and the bond. which help with the clearance of discarded metal chips in the grinding process.
Have a burning question about grinding? Check out our grinding FAQ videos for the answer
When the wheel is in use, the abrasive grains cut into the material that is being ground, removing the unwanted surface material in small chips.
During grinding, the cutting points on the abrasive grains are worn flat; becoming increasingly blunt. At the same time, the increased friction causes a build-up of heat, which fractures the abrasive grain and exposes new cutting edges or begins to disintegrate the bond bridges that hold the abrasive grains in place.
In normal vitrified grinding, the wheel has to be dressed using a dressing tool. By varying the properties of the abrasive, the type of bond, the wheel’s construction, it is possible to produce grinding wheels with a vast range of different grinding characteristics.
What abrasives are available for grinding wheels?
There are 4 main types of abrasive grains available for grinding wheels, these are:
Ceramic Aluminium Oxide
Often referred to as just “Ceramic”, Norton Quantum’s patented ceramic form of aluminium oxide is harder and sharper than conventional abrasive grains.
This ceramic grain has a unique microcrystalline structure that is self-sharpening. This ultimately reduces the regularity that the grinding wheel needs dressing as well and providing a significantly cooler cutting action when in use.
Harder than standard aluminium oxide with a very sharp abrasive grain. It is a versatile material, recommended for grinding relatively soft metals such as aluminium or cast iron but can also be used on extremely hard materials such as cemented carbide.
For use in rough grinding applications where high stock removal is required. This grain is associated with high tech resin bonds.
Generally recommended for grinding materials of high tensile strength, such as stainless steel and tool steels but it can also be used on some high tensile aluminium and bronze alloys.
Aluminium Oxide is manufactured in varying qualities.
Reading the grinding wheel
When selecting the perfect wheel for your project, it is important to know what the pictograms mean on the front blotter.
This guide will help you decipher they mean:
What grit size do I need?
When to select a coarse grit size: where the neatness of the surface finish is not essential to the project, a coarse grit can be used. Also, the coarser the grit, the more Rapid the stock removal, which makes it more suitable for large areas of contact than fine gritted abrasives.
They are also the best option for soft, ductile and stringy materials such as soft steel and aluminium.
When to select a fine grit size: fine grits are used when the finish is integral to the success of the project.
Also, choose a finer grit when the project requires a closer, more precise operation over a smaller area of contact. Hard and potentially brittle materials such as glass, tool steel, and cemented carbide are most suited to the finer gritted abrasive.
What grinding wheel grade should I choose?
The grade indicates the relative holding power of the bond, which holds abrasive grains in a wheel.
For hard materials such as hard tool steels carbides
For large areas of contact
For small or narrow areas on contact
Selecting the right grinding wheel
There are nine main factors to be considered when selecting a grinding wheel for any application:
What material will you be grinding and how hard is it?
What stock needs to be removed from the material?
Work out the shape of the material and the surface finish (or finishes) that are required.
What type of machine will you be using? Pay attention to its power and its conditions.
What wheel speeds and feeds will be involved? (Norton products are designed and tested for certain applications and operating speeds.
In the interest of safety, please take the time to ensure that the operating speed of the machine does not exceed the maximum operating speed as it is marked on any given product.
Determine the size and hardness of the grinding contact area.
Will your grinding operation be a wet or dry process?
What is the severity of the grinding required?
What is the dressing method?
What material will you be grinding?
The type of material affects the selection of abrasive, grit size and grade.
- Alumina type abrasives are the most suitable for grinding high tensile materials such as steel and ferritic cast irons. The more friable types of alumina are preferred on harder steels and applications having large arcs of contact.
- Low tensile strength materials and non-metallic materials are most efficiently ground or cut with silicon carbide abrasive. The hardness of the material governs the amount of penetration that can be achieved by the abrasive.
- For this reason, finer grit sized wheels are required to grind hard materials and soft materials are best ground with medium to coarse grit size wheels. For most efficient operation, the grade must be adjusted to suit the hardness of the material.
As a general guide, the harder the material, the softer the grade of wheel required.
Stock/material to be removed
- High stock removal rates, as in fettling operations, require coarse grit wheels, typically 12 to 24 mesh.
- Fine finishes and tight limits on finished workpiece geometry require finer grit sizes. Final surface finish is often achieved by ‘spark out’ where no further infeed is applied and the wheel is allowed to grind until the majority of the grinding sparks cease.
Hopefully this guide has helped you make in making the most informed choice possible.
In most cases (particularly within maintenance, repair and operations) you would typically use a grinding wheel on an angle grinder.
Our article on angle grinders explains why they should be an essential item in any toolbox, shed, or workshop.
If you have some specific questions about grinding, why not try our new grinding FAQ section or send us an email.
Interested in buying Norton products? Try our handy where to buy feature.
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Grinding wheel choices?
i am setting up a grinder station to grind my tools and have ?s regarding wheel types used. First off I will be grinding lathe bits, drills, and possibly endmills. I have the Harold hall grinding jig book on the way to help with angles. My question is more of what kind of wheel to use. Meaning cup, plate mounted, regular flat face.
The drill sharpener says to use the side of the reg. wheel, and while this may be ok by somewhere else, I am wildly uncomfortable doing this. I’m sure the front face would work with a rigid setup to eliminate flex, but if it ever does catch their will lots parts and pieces a flying. So pre thought would be a plate mounted wheel to do drills, (prob. Alum oxide) and hss lathe tools. And a green for lathe carbide. Am I correct that u only use the face of a plate mount wheel? And as for endmill sharpening I’m guessing a diamond cup wheel, I may want to sharpen the side flutes later on as I get through Harold’s book, but for now just the face.
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I was taught to use only the front of the wheel of a bench grinder. Using the side of the wheel was always a big no. Toolroom wheels and how they are used is different because the cut is much more controlled than offhand grinding. I am looking at setting up diamond wheels for finishing of my tools. Rough grinding if required using the bench grinder
I’m really going back to your previous dilemmas with boring tools. or whatever. There is precious little to fault Hall’s book except that things are changing and probably adding diamond and CBM would help you enormously. However, I would suggest that you read and absorb John Moran’s GadgetBuilder.com’s web pages. I’ve been over the text etc and. whilst I may take issue about the Deckel clone, you would benefit from the two simple jigs as starting points. The little amount of effort required to make and use them means that if they don’t suit you that you haven’t lost much.
Again, I strongly suspect that your previous efforts have been thwarted by your failure to do as Tom Walshaw wrote as Tubal Cain, it is all to do or not to do with that little bit at the end of the tool that matters. I would seriously suggest that you ‘black in’ the little bit with a waterproof marker and hone it away with diamond paste or film. Conrad Hoffman. I’ve mentioned him before- gives a blow by blow discourse in his Advanced Tool Sharpening site.
If you want to make turnings which are barely dust and your work shine as well as ‘mike’ try Walshawand Hoffman.
I think that attention to the final honing would help you enormously.
For sharpening brazed carbide bits, use a green Silicon Carbide wheel for rough shaping, and a Diamond wheel to dress the finial cutting edge. (bench grinder with each wheel type per end). For sharpening HSS bits, use aluminum oxide wheels only (bench grinder with one coarse and one fine aluminum oxide wheel). Do not sharpen HSS with Silicon Carbide or Diamond wheels.
Never grind on the side of a grinding wheel unless it’s specifically advertised as being design/rated for side loading. Bench-grinding wheels designed for cutting on the side, in lieu of just the outside face exist, but these are not common, and typically cost more.
Custom sharpening equipment will use custom wheels (cup, plate, other.) whereas bench grinders use standard wheels. The advantage to custom sharpening equipment is that there’s normally precision jigs for tool positioning. The disadvantage to custom sharpening equipment is the high cost.
Grizzly sells a sharpener for use with side-loaded wheels. They also sell just the wheels. This unit (linked above) is intended to sharpen planer and jointer knives, but can also be used as a side-loaded bench grinder wheel.
I have a CBN wheel with a 160 grit which will do both hss and carbides. Using a green grit is a first class way to fill the workshop with clouds of grit.
As for steel and diamonds and the alleged destruction of the carbon with heat, it is simply an old wives tale and sadly Entropy has joined the knitting or nothing circle.
Here again, practice and theory differ. With care, a worker with little experience can use diamonds and more importantly, create a mirror like tool edge which- as we know( or not) impart and equally mirror-like finish to the work.
What has to be avoided is the negative tool angles often on cemented carbide inserts which give the necessary rigidity and horse power to push away unwanted metal. I have no doubt that the normal home workshop small model maker’s lathe does not have either attribute.
Again, I am writing for the amateur and not for those who sadly have to earn their pennies on large machines. Someone has to but this is a hobby- no more.
Years ago, I actually made bonds for abrasive wheels and also help design tungsten carbide cutters for cutting rockwool- for an American company who was having problems on their Dankhaert machines. Happily, not sadly, I put my sliderule away and went on to playing with counting beans for a while until I said ‘Enough, I have enough’ and raised two middle aged fingers to having to work- for someone else.
Incidentally, I have a Clarkson, a Quorn which I made, a Kennet, a Stent that someone made by welding( and died) and I’m playing with one of these Chinese Deckel things with two types of diamond wheels and a 80 grit ordinary wheel. I also dabble in Goneostats and ornamental turning but I’m writing for a young? person with limited experience and success.
Yah Sucks. Is that the expression?
Naiveambition, it’s best to use some sort of dust collector system when using grinding wheels inside. A shop-vac with high efficiency filter works well. Another option is to use a small duct blower, and simply discharge the air outside (what I do for welding fumes, and grinding dust). If you live in an area with nice weather year-round, you can always put your bench grinder outside under an awning.
I’m not sure what goldstar is referring to with diamonds and heat. Aluminum oxide sharpening HSS just fine, and diamond wheels are quite expensive.
I’m not sure what goldstar is referring to with diamonds and heat. Aluminum oxide sharpening HSS just fine, and diamond wheels are quite expensive.
Not bad for a kid who left school at 14 after what was a miserable war time education- so Thank you!
Diamonds are pure carbon and therefore there is a faction that claims that the heat generated in grinding a diamond wheel will be quickly destroyed. I amongst many others does not subscribe. As for price, diamond or more correctly synthetic ones is remarkably cheap and if you had followed the excellent advice of Bazmak ear lier you would have read how cheap these wheels (and- pastes) are.
When they were dear, my first one came from a firm which shaped lenses and somewhat tenuously, my wife who was a Fellow of the Royal College of Surgeons played bari sax with an optician who played base clarinet who had an ‘in’ with the local optical works and.- I wasn’t one to miss an opportunity! Sadly, neither person is now with us but the diamond wheel is. I went back to help an nonagenarian who had built a ‘Long wheel base’ Stent tool and cutter grinder and he still has his. We often re-sharpen TC masonry drills- being Old Age pensioners and short of disposable income. ( Ahem!)
So that NA if you are still with us, I suggested that you access Gadget Builder.com and he built a Brooks.Stent from the writings of Derek Brooks and was published in Model Engineers Workshop issues 16 and 17. I still have copies on file. But reading on, Brooks used his machine to grind needle valves for his model engines. I have the ‘short ‘ Stent which was weld fabricated from mild steel sections and like the misconceptions of steel rubbing against steel works remarkably well.
So NA, you have long and hand on experience.
How to Use A Drill as grinder (Convert Drill to Grinder)
Don’t want to buy another expensive tool for the shed?
Are you using your drill to the fullest potential?
Need to sharpen some rusty or worn out tools? In this article I will show you how to turn your everyday drill into a tool sharpening station or a grinder so that you can get the best value out of your drill.
How to use a drill as a grinder
There can be many reasons why you may need grinder, whether it is to shave the rust off a metal part, polishing and cutting tiles, or even fix your ugly paint jobs here and there, you can accomplish all that without dropping your wallet on an actual grinder. Grinders are pretty pricey and if you do not plan on using it for a lot of jobs then you would be better off with a grinding attachment.
These attachments allow you to convert your drill into a grinder by simply plugging the attachment into the drill head. There are safety precautions and limitations to what a drill grinder can do as this is only a quick alternative as you most definitely won’t be able to get full grinder capabilities out of your drill.
How to attach a grinding wheel to your drill?
First thing to do after you grab all of your parts needed is to see which side fits into the drill head. After that, take a look at the adapters and check if only one or two screws are used as it will tell you on how to install the grinder onto the adapter. If there is a separate screw that goes into the other half of the adapter(should be shaped like a hole) then simply attach the grinding wheel onto the lone screw and then attach it back into the adapter.
Make sure to tighten the adapter end so that the wheel does not wobble when in use. However, if your adapter only comes in one long screw with two washers and nuts, loosen up the nut on the adapter with the ½ shank and slide the grinding wheel in. After that slip the washer and nut back into the screw and tighten it all the way to prevent slippage. When you use the grinder, make sure to always wear gloves and safety glasses to prevent injury to the eyes and skin. When you slip the adapter back into the drill head, be sure to tighten the drill head once it is fully in.
Some drills have a special screwdriver made specifically for the drill head. If that is the case then make sure to fully insert the arbor adapter in and use the screwdriver to tighten the holes on the drill head. This same assembly method can also be used for putting on other attachments like a wire brush for polishing, a metal cutter to cut tile, wood and metal, or sandpaper for sanding and buffing.
If you do not feel like going out and buying the grinding attachment and you only need to sharpen a small item, I will show you how to make a one time grinding wheel from an old CD and sandpaper. Be aware that this will be only suitable for sharpening/grinding small items and even then It won’t be that good…
First, take the CD and trace it out on the sandpaper (make sure to trace twice). Then use a sharp tool to carve out the center hole big enough for a screw to fit in. Slip one layer of sandpaper into the screw along with a washer and then insert the CD inside. You may apply glue to tape the layers but it is not as the centripetal force will push the paper back. Insert a nut and another washer and tighten both ends with a wrench. Lastly, insert the screw end into the drill and tighten. This method will work if you only need to sharpen small bits and will not work against big projects like polishing mortar or cutting something!
How to use drill as a grinder
When operating the grinder there are a few safety tips that you should keep in mind if you still want to keep your hands and fingers after this. Rule number one is to always unplug the drill or make sure it is switched off whenever you change out the wheel. The second rule is to never apply pressure while you are grinding. This is because the speed will take care of the hard lifting and pressing down will only break the wheel in pieces causing the shard to possibly cut your eyes.
The third rule is to never aim the wheel at a very sharp angle as this can jam the wheel into the material causing the wheel and the drill to break apart. Depending on the material you use to grind the angle should be 20-30 degrees. If you are cutting, then the wheel should be 90 degrees straight down towards the material. Sanding material away should be at a 5-10 degree angle and the wheel should only be touching by about one inch. If using a wire brush, also keep a 5-10 degree angle and only let the tip of the wire brush come in contact with the material. The last rule is to always make sure the wheel stops spinning before you set the drill grinder down on the table.
What you should be aware of.
When using the drill as a grinder, you will not have as much stability as if you bought a regular angle grinder. This is due to the extra handle in the angle grinder not being present on the drill. Another thing to consider is that when you grind metal with metal, sparks will fly out so wear heat resistant gloves. When choosing the right grinding wheel, it is important to check the max rpm of your drill and the wheel. The grinding wheel max rpm must be greater than the max rpm of the drill or else the wheel can shatter fly off the drill and rickshade as it comes into contact with something since the speed is too much to handle. Also, be aware that a drill just won’t have enough power to cut large items and it will be Considerably slower than an actual angle grinder.
Best grinder attachments for drill
For all purpose grinding, such as cleaning up metal or sharpening tools, I recommend a standard grinding wheel as it is a one size fits all.
For cutting metal, the cutting grinding wheel is the best one for this job as it is very sleek and sharp. There is a higher chance of this wheel snapping and bending since the thickness is smaller than a standard wheel.
For cleaning paint and rust, the wire brush wheel will finish the job faster than any other grinding wheel. Wires tend to fly off this wheel over time and can scratch the skin pretty hard without protection. Make sure to choose a high quality wheel for this one and do not cut corners on price.
Metal grinding attachment for drill
If the size of your job is not gigantic, this metal grinding attachment will suffice rather than attaching a big wheel onto your drill. This piece goes for a few bucks and its small shape allows you to use the drill to curve and shape metal.