Particle size comparison table.
The particle size comparison table allows you to identify abrasive belts in different grain identification systems.
When you start building knives one of the first things that are clear is that the knowledge of the grains of abrasive belts and the abrasive paper is essential to be able to finish the various materials of the blades and the knife handle, whether wood, micarta, G10 or resins, and to realize the satin finishing of the blade or polishing.
The uniformity and dimensions of an abrasive granule are ensured by technically precise control procedures in order to ensure the machined parts an economical, effective, uniform and as perfect as possible sanding.
The identification of the size of the abrasive granules is based on the number of meshes present in a square inch of a sieve through which the granules of different sizes pass.
The sieves arranged in series, vibrating, allow the passage of the granules from the thinnest (grain 220/240) to the largest (grain 16).
The finer grains are separated with other systems (hydraulic sedimentation or atmospheric flotation).
The number of sieve meshes determines the size of the grain.
In a series of sieves if a grain passes through a sieve with 60 meshes per inch but is retained by the next one, said grain will be identified with “grain 60”
For the identification of grains there are more standardizations.
The most common are FEP A granulometry (European) and CAMI (American) particle size.
They are very similar from grain 16 to 220 but have significant differences in the finer grains.
In FEP A particle size, the grain number is always preceded by the letter P.
For example, on a grain 60 the wording stamped on the product will be P60, while on a grain 220 there will be the words P220.
There are also other identifications for the size of the abrasive granules, on micro formed abrasives for example the dimensions are expressed in microns (thousandths of a millimeter) corresponding to the measurements of the single granule.
In this case usually the number of the grain is preceded by the letter X.
- We therefore see that a FEP A P1200 grain will correspond to a CAMI 600 grain while on a micro format product it will be stamped X16 grain
Comparison table of grain sizes for abrasive grains on support.
Comparison table of particle sizes.
This classification concerns abrasive grains applied on a support (fabric and paper).
The European FEPA system provides for a classification recognizable by the letter P placed before the grain number (P 36 / P 600 .. ).
This table is intended to provide a comparison tool between the different classifications, without the claim of completeness and accuracy.
- FEPA (Fédération Européenne des Fabricants de Produits Abrasifs) is the European Association of Abrasive Manufacturers. FEPA distinguishes two grains: applied on canvas and paper support (FEPA P) and abrasives (FEPA F), e.g. for abrasive stones and grinding wheels. FEPA distinguishes between the abrasive grain used for flexible abrasives, i.e. abrasive cloths and papers (FEPA P scale) and that used for rigid abrasives, i.e. grinding wheels with hole or stem (FEPA F). We are therefore interested in the “P” scale. The grains are defined by the number of lines per inch (25.40 mm) on the sieves used to separate them from each other. A P150 grain then has to go through a sieve with 150 lines/inch, but not from a sieve with 180 lines/inch, from which passes the P180. And so on.
- ANSI (American National Standards Institute) is the American regulatory institute. This scale is also very little used in the field of Flexible Abrasives.
- JIS (Japanese Industrial Standard) is the standard of the Japanese Standards Association, which is responsible for Japanese standards. It is the scale issued by the Japanese Association of Standards. Rarely used: Even the Japanese tend more and more to use the FEPA scale.
- MICRON (μ). One micron corresponds to one thousandth of a millimeter (0.001mm). The Micron column is useful for providing a common comparison tool. A micron, also referred to by the Greek letter , is one thousandth of a millimeter (0.001 mm). It is the scale used to measure micro grains not provided by FEPA scales, and, which is most important to us, is used to measure the grains of diamanated abrasives and CBN.
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