Back in the bad old days, when you needed to grind chisels, your only option was a high-speed electric grinder with really coarse, gray wheels of indeterminate composition. You learned to constantly dunk your blade in water, or you would get the blue coloring of a burned blade. Then along came white wheels, which made life a little easier, but you could still burn a tool if you weren't careful. So a lot of people switched to very expensive wet grinders. These wet grinders were miniatures of the big wet grinders one would find in industry, and they generally cost a lot. Suddenly we all felt compelled to spend hundreds of dollars on fancy machines. These wet grinders, of course, have a fatal flaw - they work s-l-o-w-l-y.
Fortunately, we're in the next generation. Norton Abrasives, one of the largest abrasive companies in the world, developed these grinding stones a few years ago for use in industrial grinding applications. They are now making them in sizes appropriate for regular grinders and at an affordable price.
These are the coolest running grinding wheels we have ever seen. We put one on our old high-speed 6" circa 1978 $50 grinder and started grinding everything in sight. We are doing a lot of hollow grinding because the risk of burning the steel is so much reduced. Of course, hollow grinding saves a lot of honing time, which suits us just fine. And unlike a wet grinder, the wheels grind really fast - perfect for busy woodworkers.
These wheels are typcially "I" grade which is perfect for cool running and grinding regular edge tools. We also stock "K" grade wheels are a little harder, run a little hotter, but are less friable. For grinding turning tools made out of HSS (which can run very hot without burning the steel) the "K" wheels will grind a little faster and maintain wheel shape longer.
Like all grinding wheels, these wheels should be regularly dressed, in order to remove any glazing on the wheel and to open the pores of the stone so that the stone cuts cleanly, quickly and coolly. The 6" wheels have a 1" hole with adapters to fit 1/2", 5/8",3/4",7/8", or 1" arbors. The 8" wheels have a 1" hole and adapters for 5/8, 3/4", 7/8", or 1" arbors.Dimensions on the table refer to diameter and width.
"The coolest running grinding wheels I have ever used."
--- Barry Iles, Ashley Iles (Edge Tools) Ltd.