Most woodturning tools today are made from high speed steel.
These call for grinding wheels made from aluminium oxide for easy, high quality sharpening.
Confusion over the wheels is easily fixed.
Manufacturers make money by selling lots of wheels.
They also make money by catering to the needs, real of perceived, of consumers.
Woodturners appear to be very able consumers as evidenced by the magnitude of offerings in woodturning catalogues.
The desire to have sharp tools with long lasting edges has generated a compelling market filled with tool steels, sharpening jigs, fancy grinders and of course, grinding wheels.
Aluminium oxide has become the grinding material of choice for woodturners.
It is a naturally occurring substance with a high hardness quality suitable for working steels and many other compounds.
Its most common form, corundum, is a clear material although it takes on many colors with different impurities.
This clarity allows it to be easily masked or coded for use by manufacturers by using bonding agents of different colors to identify densities or friability.
Aluminum oxide is for all intents and purposes of uniform density but a grinding wheel made from it will vary from another by the ability to break off particles, its friability.
The more friable a wheel the cooler it grinds and the easier it is to dress.
It also stays cleaner and grinds a bit better as the outer surface breaks away to reveal new crystals.
However, extremely friable wheels groove easily and require frequent dressing which in turn means loss of size and material.
This leads to frequent wheel changes which are better for the manufacturer than the consumer.
So how friable a wheel do you need for woodturning tools? Almost any on the consumer market are friable enough for modern steels.
It is virtually impossible to ruin the temper of a high speed steel tool by grinding on home grinders so the coolness of the grind is not an issue for most.
In addition the common grinding wheel will last longer than the white, pink or blue ones sold for woodturners.
More important is a grit that allow for a good edge and a dresser that keeps the surface of the wheel clean for quick sharpening.
The real trick is to relax and sharpen the tools so as to get back to the wood lathe.
There is a great enjoyment in good wood, well turned with sharp tools.
These call for grinding wheels made from aluminium oxide for easy, high quality sharpening.
Confusion over the wheels is easily fixed.
Manufacturers make money by selling lots of wheels.
They also make money by catering to the needs, real of perceived, of consumers.
Woodturners appear to be very able consumers as evidenced by the magnitude of offerings in woodturning catalogues.
The desire to have sharp tools with long lasting edges has generated a compelling market filled with tool steels, sharpening jigs, fancy grinders and of course, grinding wheels.
Aluminium oxide has become the grinding material of choice for woodturners.
It is a naturally occurring substance with a high hardness quality suitable for working steels and many other compounds.
Its most common form, corundum, is a clear material although it takes on many colors with different impurities.
This clarity allows it to be easily masked or coded for use by manufacturers by using bonding agents of different colors to identify densities or friability.
Aluminum oxide is for all intents and purposes of uniform density but a grinding wheel made from it will vary from another by the ability to break off particles, its friability.
The more friable a wheel the cooler it grinds and the easier it is to dress.
It also stays cleaner and grinds a bit better as the outer surface breaks away to reveal new crystals.
However, extremely friable wheels groove easily and require frequent dressing which in turn means loss of size and material.
This leads to frequent wheel changes which are better for the manufacturer than the consumer.
So how friable a wheel do you need for woodturning tools? Almost any on the consumer market are friable enough for modern steels.
It is virtually impossible to ruin the temper of a high speed steel tool by grinding on home grinders so the coolness of the grind is not an issue for most.
In addition the common grinding wheel will last longer than the white, pink or blue ones sold for woodturners.
More important is a grit that allow for a good edge and a dresser that keeps the surface of the wheel clean for quick sharpening.
The real trick is to relax and sharpen the tools so as to get back to the wood lathe.
There is a great enjoyment in good wood, well turned with sharp tools.
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