Is the Grit Unit Antiquated?

Is the Grit Unit Antiquated?

A call for standardization

January 22, 2019

The most common unit utilized in the world of abrasives is the grit. The unit is supposed to delineate the size of the abrasive particle scratching the surface during sharpening, smoothening, and/or flattening (or whatever variation of abrading is happening between a harder and a softer material). A unit of measurement born of a time lacking in uniformity of production methods, the number is not a definite value, but rather represents a range of sizes that an abrasive particle could be.

This raises an issue for most as there is no standard between producers of abrasives, leading to inconsistent scratch patterns throughout the honing process; first, because there are different size particles polishing a given surface, and second, the range of particle sizes is even greater when switching between varying grit sizes, or especially heightened, between different brands.

There are two logical answers to address this issue:

1. To create a standardized conversion between a grit size and the average micron size of a given abrasive particle. Attempts at this have been done, but not without a lack of uniformity between brands.

2. A solution more simple in that it would not require an agreement between competing entities, is merely to use micron as the unit of measurement. Skip the grit altogether. It is as simple as that.

Nano Hone is suggesting such a move in printing the micron size directly onto our sharpening stones and lapping plates to show clearly what the objective size of the particle is (the grit size is there as well, but let it be a reminder that it is a range). To support the move to micron-centric sizing, purchase Nano Hone or ask your sharpening community, why are we using a range to talk about a size?

Nano Hone Backing Plates shown sporting smart display of measurement

The micron is used, already, in measuring super fine abrasives, so now that the technology for fine consistency is more widely available, why not refine our vocabulary along with the measurements?


Would it make more sense to purchase plywood with the thickness designated by a non-standard estimate of thick or thin? Or to simply choose the sheet based on the objective thickness? The point of the Mohs scale was to create a standard of measurement of hardness. It works because objectivity ruled over subjective observation.


In the world of sharpening, it would be better late than never to start measuring more objectively. An agreement of terms is what allows for common understanding.


Sumimoto A. is a contributing bard for the Nano Hone blog. 


Click here to view our micron-labeled stones and lapping plates.

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