Tag Archives: Abrasive Stones

From the Archives: How Do Grinding Wheels Work?

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This article is from our archives. Let us know in the comments section if you found it helpful or interesting!

Our article on diamond blades drew a lot of interest, so we’re going to follow it up today with a discussion on grinding wheels.

Before we start talking about grinding wheels, though, we should first pin down what we mean by “grinding wheels”. After all, there’s grinding wheels, grinding stones, grinding cups, grinding points, and the list goes on. Therefore, to narrow our discussion, we’re going to confine this article to straight wheels – that is, flat grinding wheels that grind with their faces.

How Grinding Wheels Work: Grinding wheels are similar to the diamond blades that we talked about earlier. They both have some kind of hard, abrasive grit that’s usually held in some kind of bond. The grit scrapes chips out of the material that you’re grinding or cutting, while the bond wears away to shed worn grit and expose fresh, sharp grit buried deeper in the wheel or blade.

Which Grinding Wheel You Should Use: You need to consider three things when choosing a grinding wheel: abrasive, bond, and grit size.

Abrasive: You should match the abrasive in your grinding wheel to the material that you’re grinding. Here’s some of the most common abrasives:

  • Aluminum Oxide: Designed for grinding carbon, stainless, and high-speed steel, malleable and wrought iron, aluminum, and bronze.
  • Silicon Carbide: Designed for grinding cast, gray, and chilled iron, non-ferrous metals like soft bronze, brass, and aluminum, and non-metallic materials like concrete, brick, marble, stone, rubber, and glass.
  • Zirconia Alumina: Designed for high stock removal of steel and steel alloys. Resists higher temperatures and pressures.
  • Ceramic Aluminum Oxide: Designed for precision grinding of tough materials like stainless steel, titanium, and high-nickel alloys.
  • Superabrasives: Extremely hard and expensive materials like diamond or cubic boron nitride. Designed for grinding very hard materials that may defeat other abrasives.

Bond: Most grinding wheels have their abrasive grit bonded either directly to a metal or rubber disc or within vitrified or organic resin bonds. However, what matters isn’t the bond itself, but its hardness.

Grinding wheel bonds are similar to diamond blade bonds: harder bonds last longer, while softer bonds grind faster and with less pressure. You can tell the hardness of your wheel’s bond by a single-letter code on the wheel, with A as the softest and Z the hardest.

Grit Size: This is a big factor in a grinding wheel’s speed and finish. Grit size works pretty much the same for grinding wheels as it does for sandpaper: larger, lower grit grinds faster and and leaves a coarser finish, while smaller, higher grit grinds slower and leaves a smoother finish.

Dangers of Grinding Wheels: Remember, grinding wheels are designed to grab onto things and scrape chips out them while spinning insanely fast, and they don’t care what they grab onto or where they throw those chips. Therefore, you should always take precautions when grinding, including:

  • Wearing personal protective equipment like safety glasses and gloves.
  • Making sure your grinding machine’s guards are installed and in place.
  • Taking off or tying back loose clothes.

In addition, certain grinding wheels pose their own risks, including shattering and emitting hazardous silicon carbide fibers.

Shattering: Vitrified and resin grinding wheels fly apart if they’re nicked, damaged, or run at too high a speed. These accidents produce shrapnel that can injure or kill the grinder operator.

To prevent shattering, you should check these kinds of grinding wheels for cracks and large nicks before and after using them. The Oklahoma State Regents for Higher Education recommend the “ring test” – that is, lightly tapping the edge of a vitrified or resin wheel with a non-metallic object before starting it up. If you hear a dull thud instead of a metallic ping during this test, throw out the wheel and get a replacement.

You can also help prevent grinding wheel damage by:

  • Carrying the grinding wheel to your grinder instead of rolling it, no matter how big it is.
  • Running it within its recommended RPM.
  • Grinding with only its face instead of its edge.

OSHA also recommends standing off to one side when you start up your grinder and then letting it run for a full minute, just in case your grinding wheel does shatter.

Silicon Carbide Fibers: Grinding wheels with silicon carbide abrasive pose a special hazard: emitting silicon carbide fibers during grinding that can lodge in your lungs. Long-term exposure to these fibers has been linked to increased mortality from asthma, emphysema, chronic bronchitis, pneumoconiosis, and lung cancer. We therefore recommend that you wear a respirator whenever you use or are around silicon carbide grinding wheels.

Of course, you can avoid shattering wheels and inhaling silicon carbide fibers by using a metal grinding wheel instead of a vitrified or resin one, like the Safety Blade Grinder/Cutter. The Safety Blade Grinder/Cutter is made of solid steel, so it won’t shatter or break apart under normal use. In addition, its thick coat of diamonds grinds a wide variety of materials, including iron, steel, non-ferrous metals, high-nickel alloys, welds and welding slag, concrete, asphalt, brick, block, stone, you name it.

Works Cited

“Abrasive Wheel Grinder Safety.” System Safety, Health and Environment Resource Center. Oklahoma State Regents for Higher Education, n.d. Web. 28 Aug. 2013. < http://www.okhighered.org/ssherc/newsletters/osrhe/abrasive-wheel-grinder-safety.html >.

“Grinding Wheel.” Wikipedia. Wikipedia, 9 Apr. 2013. Web. 28 Aug. 2013. < http://en.wikipedia.org/wiki/Grinding_wheel >.

“Grinding Wheel and Abrasives Basics.” Georgia Grinding Wheel. Georgia Grinding Wheel, 25 Nov. 2008. Web. 28 Aug. 2013. < http://www.georgiagrindingwheel.com/grindingwheels_basics.htm >.

“Hand and Power Tools – Hazard Recognition.”  Occupational Safety and Health Administration. Occupational Safety and Health Administration, May 1996. Web. 28 Aug. 2013. < https://www.osha.gov/doc/outreachtraining/htmlfiles/tools.html >.

“How a Grinding Wheel Works.” Flexovit Abrasive Products. Flexovit Abrasive Products. Web. 28 Aug. 2013. < http://www.flexovitabrasives.com/education/performance/how-a-grinding-wheel-works/ >.

“How Do Diamond Blades Work?” Desert Diamond Industries’ Blog. Desert Diamond Industries, 27 Aug. 2013. Web. 28 Aug. 2013. < https://desertdiamondindustries.wordpress.com/2013/08/27/how-do-diamond-blades-work/ >.

Sullivan, Joe. “Choosing The Right Grinding Wheel.” Modern Machine Shop. Gardner Business Media, 15 Dec. 2000. Web. 28 Aug. 2013. < http://www.mmsonline.com/articles/choosing-the-right-grinding-wheel >.

“Q. What’s the Difference between Abrasive Wheels and Blades and Diamond Grinders and Blades?” Desert Diamond Industries Blog. Desert Diamond Industries, 2012. Web. 28 Aug. 2013. < https://desertdiamondindustries.wordpress.com/2013/11/13/q-whats-the-difference-between-abrasive-wheels-and-blades-and-diamond-grinders-and-blades/ >.

From the Archives: How Does a Diamond Blade or Diamond Grinder Differ from an Abrasive Blade or Abrasive Grinder?

How Does a Diamond Blade or Diamond Grinder Differ from an Abrasive Blade or Abrasive Grinder?

This article is from our archives. Let us know in the comments section if you found it helpful or interesting!

A diamond blade or diamond grinder differs from an abrasive blade or abrasive grinder in its construction. This may not sound like an important difference, but it can affect both your health and your safety.

An abrasive blade or abrasive grinder has extremely hard materials like silicon carbide and/or aluminum oxide bonded with resin and mesh into a disc. When spun at high speed, these hard materials wear away the material being worked, producing a ground surface or a cut.

This kind of construction has several disadvantages: it wears away quickly, grinds or cuts slowly and produces massive amounts of sparks during grinding or cutting. More importantly, an abrasive grinder or abrasive blade can threaten your life and your health.

An abrasive blade or abrasive grinder can endanger your life because it can shatter during grinding or cutting and spray you with fragments that can injure or even kill you. The Occupational Safety and Health Administration (OSHA) has numerous reports of injuries and deaths caused by shattering abrasives. You can view some of these reports here, here, herehere, here, here, here, and here.

An abrasive grinder or abrasive blade can also endanger your health because it emits silicon carbide fibers during grinding or cutting. According to the New Jersey Department of Health, silicon carbide can cause a chronic lung disease called pneumoconiosis with long-term exposure, and there’s limited evidence that silicon carbide can cause lung cancer, at least in animals (PDF). Additionally, silicon carbide workers have reported increased mortality from asthma, emphysema, chronic bronchitis, pneumoconiosis, and lung cancer, according to OSHA.

A diamond blade or diamond grinder, on the other hand, has diamond particles attached to a steel core. Because it’s made of steel, a diamond grinder or diamond blade is generally safer than an abrasive grinder or abrasive blade and won’t shatter or emit silicon carbide fibers during cutting and grinding.

Keep in mind, however, that not all diamond blades are the same! A common kind of diamond blade has diamond cutting segments welded onto a steel core. These welds can soften and break during extended cutting. If they do, the segments can fly off and strike the operator, causing injury or death like an abrasive blade.

For this reason, you’ll want to avoid using a welded diamond blade and use a solid steel diamond blade or diamond grinder. A solid steel diamond grinder or diamond blade might bend during cutting, but it won’t break, increasing your safety. After all, you deserve to go home at the end of the day, instead of the emergency room or the morgue.

For more information, visit our FAQ page.

Works Cited after the break.

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The Dangers of Shattering Abrasive Blades, from WorkSafeBC

Safety Articles from Desert Diamond Industries

It may seem like we harp on the dangers of abrasive blades and grinders here, but it’s for a good reason: the things can kill you.

To hammer that point home, we’re featuring this safety video on abrasive angle grinder blades from WorkSafeBC today on the blog. It has plenty of tips on how to use abrasive blades safely, but it also shows – pretty effectively, we think – the consequences of shattering abrasive blades.

We think the risks that abrasive blades pose are too great, not matter what precautions you take. We recommend that you cut with diamond blades instead. After all, why take any chances?

WARNING: This video contains graphic content.

I Angle Grinded My Head in Half, or THIS Is Why You Don’t Use Abrasive Blades (Part 2)

Safety Articles from Desert Diamond IndustriesYesterday, we promised you Part 2 of Frank Morrison’s violent encounter with a broken abrasive blade, so here it is. We should warn you, this video gets pretty graphic around 1:17. If you’re not a firefighter or emergency worker, you might want to watch it on an empty stomach.

Spoiler Alert: Morrison survived the accident, but it cost him an eye. He was one of the lucky ones, though. Shattering abrasive blades and grinders have killed their operators. That’s why we keep telling you to stop using abrasives and start using solid steel blades, like the Ductile Iron Safety Blade (up to 14″).

Thanks once again to Great Britain’s Bizarre ER.

Remember, we’ll be exhibiting the Ductile Iron Safety Blade, Ductile Iron Ring Saw Safety Blade and Carbide Chunk Blade in Booth 3087 at the American Water Works Association‘s ACE13 conference in Denver, CO from June 9 to 12! See our press release for details.

I Angle Grinded My Head in Half, or THIS Is Why You Don’t Use Abrasive Blades (Part 1)

Safety Articles from Desert Diamond IndustriesIf you ever needed a reason not to use diamond blades, look no further than Great Britain’s Bizarre ER. Their segment I Angle Grinded My Head in Half documents the 2008 angle grinder accident of Frank Morrison, who was struck in the face after his blade exploded.

The narrator calls the blade used by Morrison during the accident a “metal blade”. However, she also says that it “exploded”, which leads us to believe that he used an abrasive blade during this accident. (Not only that, but he has an abrasive blade mounted on his grinder in this video)

We should warn you that this video gets pretty gruesome around 2:21 or so. But then, things can get gruesome when you use abrasives instead of solid steel blades, like the Ductile Iron Safety Blade (up to 14″). Abrasives can and do shatter like this, and not everyone struck by them is as lucky as Morrison.

Part 2 tomorrow.

Remember, we’ll be exhibiting the Ductile Iron Safety Blade, Ductile Iron Ring Saw Safety Blade and Carbide Chunk Blade in Booth 3087 at the American Water Works Association‘s ACE13 conference in Denver, CO from June 9 to 12! See our press release for details.