2-23-2025

the KME sharpening system -- stones

The KME uses 1x4 inch stones.

The basic kit is 140, 300, 600, 1500 and is really all you need.

If you want to reprofile knives, you should get the 50 and 100.

The single most important thing is to get the whole edge to the apex all the way along with your coarsest stone. Until you have good success sharpening with the 4 stones in the basic kit, there is no point in additional stones.

Ceramic stones

Like Arkansas stones, these will not sharpen super steels well. They will remove steel matrix, leaving carbide particle untouched. On the other hand, the Spyderco sharpmaker has ceramic rods and seems to greatly improve VG10 or S30V knives. The question is what the grain size of the carbides is. If a ceramic stone can only remove or expose carbide grains, that may work just fine if the grains are really small. What may happen is that the vanadium carbides in the knife may be causing wear on the ceramic hones themselves! Use diamond to sharpen any steel with more than 3-4 percent vanadium.

Ceramic stones (and Arkansas stones) are well suited to older carbon steels.

KME sells replacement diamond stones for $25. The Arkansas stones sell for $20. The ceramic stones on the other hand are $6, and they say that if you are just looking to resharpen a knife that is in good condition, they will do fine. They label these as aluminum oxide, but also call them "ceramic". There are 60 (black), 120 (tan), and 320 (pink).

If you buy the 4 stone set, you also get a hard Arkansas stone as well. My hard Arkansas is a mottled light grey.

Dan's Arkansas stones

Note that these stones will not sharpen super steels with vanadium carbides. Diamond or CBN is required for such steels. The abrasive in novaculite is quartz (silicon dioxide).

I have two Arkansas stones in the 1x4 size the KME requires. 

Hard black
Translucent
I see KME sells these for $32 each these days. The translucent is an ultra-fine novaculite that is used to finish an edge. The black is even finer!

Some say you can't really say that one is finer than the other. They each vary -- they are a natural product (that is mined) after all. They may be the same as far as sharpening, but people are willing to pay more for pretty translucent stones.

Venev bonded stones (at Gritomatic)

These are bonded stones with the diamond impregnated in some matrix. They cost about twice what the coated stones I am now using cost, but are highly regarded. Perhaps when and if my diamond stones wear out I will look into these.

Arkansas Stones

People say these act like 2000 grit (6 micron) abrasive. Maybe.

They are natural stones, and as such you can expect variability. Consistency depends on your supplier. I found this online:

I work for an Arkansas stone mining company. It’s all about particle density. There are lots of tutorials out there about how to “weigh” your stones. Even the same mine can produce different densities of the same stone. Different mines can also produce different colors and variations of the exact same density. Weighing your stones is just a good way to know where you’re at. Dunston “hard” black is less dense and much different than colored “translucent”.

Think of it like a stone road where all pebbles are the same size. The tighter the stones are packed together, the smoother the road feels.

Lapping is really important. A raw translucent freshly cut leaves deep scratches. After being lapped with 400 grit SiC it’s completely different. I have my porcelain translucent lapped to 3000 grit -- it makes a big difference.

And most importantly, what steel you’re using it on. Stronger carbide steels are too wear resistant for Arkansas stones. Carbon steels respond the best.

Feedback? Questions? Drop me a line!

Tom's Knife Info / tom@mmto.org