How are grinding wheels defined?
Standard grinding wheels are defined
by three separate pieces of information. These are: -
Grinding wheel size
The grinding wheel size is specified by
quoting the dimensions of the overall diameter, wheel thickness
and the bore diameter.
Diameter x Thickness x Bore
The diameter and thickness are usually
specified nominal dimensions to the nearest 'mm' but the bore size
specified to two decimal places. i.e.
180 x 13 x 31.75mm
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Shape and minor dimensions
Grinding wheels can be supplied in a
wide range of different basic shapes. many of the most commonly
used International Standard shapes are shown below.
Different grinding wheel manufactures often use slightly
different methods for defining the specification of their own make
of wheel. They all generally follow the same type of format using
a code made up of letters and numbers relating to different
features within the wheel. This code is either marked on the side
of the grinding wheel, on the wheel blotter or if the wheels are
too small, on an identification card which was sent with the
For example: -
48A 602 K6V MRAA
Tip: If you have this information to hand for
grinding wheels you currently use it can really help us when
quoting or recommending wheels. Even if the wheel you are using is
not performing how you would like it to, it gives us a starting
point to work from when we need to change certain characteristics
of the wheel.
The specification code of the grinding wheel usually consists
of six basic parts:
- Abrasive Type
The index for the type of abrasive grain used is shown at the
beginning of the code.
- Abrasive Size (Grit Size)
This defines the size of abrasive grains used in the grinding
This number can range from between 10 up to 800. The smaller the
number, the coarser wheel.
- Wheel Grade (hardness)
This letter denotes the grade or hardness of the grinding wheel.
The letters A to Z characterises the degree of hardness with A
referring to the softest and Z as the hardest.
- Wheel Structure (porosity)
The structure number is shown immediately after the grade
letter. This denotes the porosity of the grinding wheel. The
higher the number, the more porous is the grinding wheel.
- Bond Type
The bond type is defined by a letter immediately after the the
structure number. This is the material holding everything
together and is usually either 'V' (Vitrified) or 'B'
(Resinoid or resin) but there are a few others.
- Special Coding (not always used)
On special or 'made to order' wheels there is often an
additional bit of code at the end.
This varies between manufactures depending on their special
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