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Which Grinder Blade is correct for which application?


How Dangerous Are Grinder Blades Really?

What are my options when it comes to cutting?

I came across this interesting thread at BladeForums:…Angle-Grinders

Now what struck me was the writer advising everybody to switch from bonded grinder cutting disks to diamond blades.

“An incredibly dangerous occurrence, the easiest way to prevent this from happening is simply not use these silicon-carbide blades, often referred to as throwaway blades. Silicon-carbide blades are 6.3 times more likely to end in death than a diamond-blade should they shatter. If it’s not curtains, the chances the injury will be serious enough to require hospitalization is 13 times greater. Opt instead for a diamond blade.”

He also states:

“Diamond-blade segment loss

Here a far less dangerous product but none the less still deadly. Diamond blade breakage is far less common than an abrasive blade shattering, diamond-blades can lose a section causing injury as well and the results are extremely deadly. Sixty percent of the time a section of diamond-blade broke off and struck an operator, death ensued (OSHA). The remaining 40% caused serious injuries requiring hospitalization.”

Are Diamond Blades the Right Choice for Cutting Steel?

Now having just compiled the South African Norton Industrial Catalogue this seemed a little strange to me as I couldn’t recall a single diamond blade in the catalogue designed to exclusively cut metal. This came from the BladeForums, remember? Don’t think they would be cutting much of anything besides metal.

Next stop was the European Norton Industrial Catalogue. Success … the 4×4 Explorer blade is rated to cut metal. But then I saw in the product description that it doesn’t seem to be designed to be a steel cutting blade at all, more of a masonry blade that can handle steel reinforcing:

“For use on granite, engineering bricks, hard paviors, reinforced concrete, concrete kerbs & slabs, medium block paviors, facing brick, concrete roof tiles, sandstone, asphalt over concrete & asphalt.
Better resistance to cracks for enhanced safety. Norton Clipper 4×4 Explorer can cut in metal (up to 5mm thickness).”

I then started a Google search to see if any competitors offer diamond blades made to exclusively cut steel. Not much success … one competitor stated its top rated blade “can cut some steel”.

Next stop was a phone call to Norton’s technical sales department and my suspicion was confirmed – with the exception of some highly specialized products, diamond blades are not meant to be steel cutting tools. The steel rating is to handle steel reinforcement in materials like concrete.

The Right Tool for the Job

Now why would anybody want to cut metal with a diamond blade if it wasn’t meant to do that, you might ask? Well I have in the past, admittedly. My thinking was that a diamond is the hardest thing on the planet therefore a diamond blade would cut anything. And it did … I managed to help my neighbour who was stuck outside of his gate as the lock wouldn’t open. One of those mean, round, shiny locks. The diamond blade cut through it without a problem.

Did I get hurt – fortunately not.
Would I do it again with the knowledge that I have now – not a chance.

So if there is, as the writer states, a 60% chance of death when a diamond blade malfunctions e.g. lose a segment, I guess it could be rather important to use it in the correct way. Personally I would stick with a Norton Quantum thinwheel for cutting steel, in my mind there is no better tool for the job.