grinder wheel color

[PapaChuck]

Hey --

Am planning to decorate my garage and am wondering about grinder wheel colors ... shocking pink? ... dazzling white?? ... powder blue??? ... JUUUUSSTT KIDDING.

But seriously, am starting to (finally) get serious bout sharpening (moving into woodturning) and am wondering about the difference between the blue, pink and white wheels. I assume they are all friable and will work OK at 3600rpm and much better at 1700rpm. What is the deal with the different colors??

I humbly await The Blast.

-- Chuck

[<marierdj]

[russellseaton1]

PapaChuck wrote:

Usually green refers to being carbide compatible. Gray is usually the "junk" wheels that come with the grinder and are useful for grinding off welding slag, etc. But other than these usual colors and purposes, the color is just whatever pigment the manufacturer puts in the mix. All grinding wheels are friable. They all will wear away, at different rates. But its the level of friability that matters for whatever type of steel/metal you are grinding away. On some metals you want a very hard almost non friable wheel. On others you want a very soft very friable wheel. As for whether wheels work better at 3600 or 1800, it depends on how the wheel was made, etc. Oneway for instance talks about this on their website. The slower speed is usually better for the person because they have more time before they burn the steel. But the actual cutting may be better at the higher speed. For woodworking tools such as chisels and plane blades, high carbon tools, I think you would want a fairly soft fairly friable wheel. For High Speed Steel tools such as woodturning tools I think you want a harder and less friable wheel than for carbon steel. Otherwise your HSS turning tools would literally eat up the grinding wheel very quickly. And you would have to use the diamond dresser to remove the grooves every time you used the wheel. I doubt you will go too wrong if you buy a wheel advertised by a woodworking supply store. They cater to the woodworker and will almost certainly have fairly friable and soft wheels. May not be exactly optimal, but will be close. May pay more than a comparable wheel sold by an industrial supply store but wheels are not too expensive.

[PapaChuck]

-- Chuck

[George]

Absolutely. Consider just how dumb turners can be to pay a premium in initial cost and decreased useful life to get a wheel that "cuts cooler" to sharpen HSS. Now carbon perhaps would benefit, but it's softer, so abrades easier.

Which, BTW, is why AlOx gray wheels are not of necessity "junk," composed as they are of the same abrasive used in the more expensive vanishing wheels. If they don't cut metal as fast at the "friable" types, who cares? Turners use their grinders for sharpening, not shaping. Doesn't that make a less aggressive cut a benefit?

[whit3rd]

No, not exactly. Natural stone and ceramic wheels can come in lots of colors, but Al2O3 (Aluminum oxide, ALOX, sapphire, corundum, main component of emery- and maybe other names) is usually manmade for these wheels, and pure white.

Pink is Cr-doped corundum (aka ruby), and is identical in grinding properties (unless the manufacturer uses the color to indicate binder or grit differences).

Silicon carbide is green, man-made, and is widely used to grind tungsten carbide (W4C, Carbolloy, C-2, C-4, etc.). Hopefully no one uses green coloring to make lesser materials look like real SiC. This is the third-hardest of abrasives, below diamond (girl's-best-friend, cubic carbon, C) and borazon (cubic boron nitride, BN)

And the black/grey grinding wheels are what sloppy SiC manufacture generates. Who knows WHAT they use for binder/filler.