Archive for May, 2018

Spyderco Stone Challenge

May 2, 2018

We recently started offering Spyderco Medium, Fine and Ultra Fine stone in 1×4″ and 1×6″ custom sizes for various sharpening systems. That is nothing major by itself, but it spurred a friendly challenge because historically, it was said that he Fine and UF were the same stone, only finished differently. I am of the mind that the Fine and UF are the same materials, and are formulated the same way, but use different sized abrasives (Fine is approx 2K while UF is approx 4K). This would explain the difference in finish as well as the cost for the stones. Konstantin from Gritomatic is of the mind that the stones are exactly identical in every way, including grit size, except there is a different surface finish/texture on the stone which influences the resulting scratches. So the gauntlet was thrown down to see if I could discern the difference between 5 fine and ultra fine Spyderco stones. The stakes are high, so we wagered a bottle of Russian Vodka vs. a bottle of Kinmen Kaoliang.

Before I continue, it must be said that both theories hold water. Natural stones such as quartz can be surface finished rougher or finer for different depths of scratch, which results in coarser or finer finishes. You see it with dressing sticks for tormek wheels, and is similar in action with raising slurry with diamond plates, and nagura or slurry/conditioning stones for synthetics. However, my stance is that regardless of the surface texture, the resulting scratches have always produced the same results under the scope despite their aggressiveness (as long a no other abrasives are introduced into the mix).

So we begin! The obligatory data info first – pictures were taken on a Dino-Lite AM4113T. There are bar measurements for 1mm at 20x and 0.2mm at 200x if you enlarge the photos.

I received 5 stones from Konstantin and was assured that there was at least 1 Fine and 1 UF in the mix. I did several “tests” to see if I could tell the difference before the scratch test. Now this is a little unfair since I have my own stones, cut and uncut, processed and unprocessed to compare to. So the first test was the thickness test. The Spyderco Fine is just a little thicker overall than the UF, so in theory, the thinner stones should be the UF. My results were as follows: Stones 2 and 5 should be Fine stones while 1, 3, and 4 should be UF. But of course, Konstantin would know this, so I could clearly not choose the cup in front of me.

So I took to the scope. First round was 20x pics against a control of my known stones. Results were interesting, and seemed pretty straight forward at first. Stones 1,2,4,and 5 were Fine while stone 3 was UF. But we knew Konstantin would know that I would use a scope, so he changed up the surface finishes to hide any immediate tells, so I could clearly not choose the cup in front of him.

Spyderco Fine Control 20x

Spyderco UF Control 20x

Stone 1 20x

Stone 3 20x

Stone 4 20x

Stone 5 20x


Onto the 200x, which would reveal even more secrets. Results were slightly different, with the 1,3,4 and 5 stones being fine and stone 2 being UF. Clearly this was starting to get dizzying…So I could clearly not choose the cup in front of me.

Spyderco Fine Control 200x

Spyderco UF Control 200x

Stone 1 200x

Stone 2 200x

Stone 3 200x

Stone 4 200x

Stone 5 200x

So seeing as the stones were lapped before I got them, and the control pics were different from what I was seeing, we lapped everything again – both my controls and the stones from Konstantin to see if that would even the field more. I spared you the 20x pics and jumped straight to the 200x. Results were 1,2,3 and 5 as Fine, and 2 and 4 as UF, so I could clearly not choose the cup in front of him!

Spyderco Lapped Fine Control 200x

Spyderco Lapped UF Control 200x

Stone 1 Lapped 200x

Stone 2 Lapped 200x

Stone 3 Lapped 200x

Stone 5 Lapped 200x

So enough games – it’s time to drink. Last test was the all out scratch test. I started off with a control 600 diamond scratch, and then make parallel scratches against the control stones. Each time I went to a new stone, including the on the controls, I reset the askew angle on the 600 diamond to erase all traces of the previous scratches so we could see a true finish. Here the results are a little more visible, ending with stones 2,3,and 5 being Fine and Stones 1 and 4 as UF. Quite a different story from the previous tests.

600 Diamond Control 200x

Spyderco Fine Control 200x

Spyderco UF Control 200x

Stone 1 Blade Test 200x

Stone 2 Blade Test 200x

Stone 3 Blade Test 200x

Stone 4 Blade Test 200x

Stone 5 Blade Test 200x


So in conclusion, I say the Fine stones are 2, 3, and 5, while the UF stones are 1 and 4. This was a tough test, to be honest. I’m glad we were able to have fun, I will post the actual grits from Konstantin when he reveals them.

Either way, it was better than getting involved in a land war in Asia. I think it’s time to drink some alcohol! Inconceivable!