Side-by-side test: SharpPebble SiC stone and Arctic Fox

[maximus83]

As promised in another thread, ran a side-by-side sharpening test of the SharpPebble 400/1000 whetstone (confirmed with their service team as being equal to about 320/500 ANSI grits) with the Baryonyx Arctic Fox (400 ANSI). The goal was to observe the sharpness and edge finish the SP 500 grit could produce compared to the AF.

Approach:

• Had 2 copies of the Schrade SCH221BK folder, which uses a soft stainless (9Cr18MoV ).
• Profiled the edges to about 12 dps as pictured below on a Norton Crystolon 100 grit SiC stone. Placed a caliper midpoint on each edge where the bevel met the shoulder, one was 0.029", the other 0.027". Close enough for this freehander.
• Sharpened the knife labeled "AF" on the AF stone, about 35 strokes per side.
• Sharpened the other knife on the SP stone (500 grit side), about 35 strokes per side.
• No stropping or other refinement was done other than a few light passes on a clean stone with each knife to deburr. Obviously I could've done a lot more to eke more sharpness from each blade, including more work on the stones, and stropping.

What I saw:

• Visible finish. Very close. The SP finish is slightly more coarse under inspection with a 30x magnifier. It is not a large difference and does not show easily in my cell phone pics.
• Sharpness tests. Identical. Both knives performed all the following tests:
  • 3 finger sticky on the edge.
  • Thumbnail test at heel, midpoint, belly, tip.
  • Shave arm hair with moderate friction.
  • Shear-cut thin receipt paper.
  • Thin catalog paper (push/draw cut with grain, shear-cut cross grain, push-cut cross grain, both knives struggled to draw cut cross grain).
  • ETA: both knives also passed @wootzblade sharpness chart test to shave curls off the surface of printer paper. The chart suggests this indicates an apex width in the range of 0.25 micron.
• After the above tests for curiosity: I stropped one knife on 1 micron cbn compound. This noticeably improved the cross-grain cutting ability and now this knife passed that test too.

Sharpening setup

Both knives after profiling on the Crystolon coarse:

Both knives after sharpening on the AF and the SP

 

[ecallahan]

Thanks for doing this. I purchased the SP 400/1000 and I really like the edge. I have a 1000 Naniwa chosera and it makes a great finisher for me after the SP. I have the AF pocket stone on the way to try out and use as a field ‘water’ stone. I like my oil stones but this will give me a good option for stones to use with water.

 

[maximus83]

Yep, these are 2 nice stones, will keep using. If I had to choose one I'd go with AF. The stone is less friable than the SP, and it's totally subjective, but I find that a bit easier to work with during sharpening. Whenever I'm working with a steel that the AlOx AF can handle well, I'll keep using that. But you can for sure get an equally good edge off the SP 500 grit, at least with the steels I've tried.

The SP in my lineup is potentially a course/medium sharpening option for high vanadium steels. That's really why I wanted to get it--to have a non-diamond SiC water stone (this is where the Crystolon fine falls short) to sharpen super steels. So the next test is going to be something like: SP vs DMT coarse, with a super steel like s30v or something higher vanadium content. The problem with that next test is I don't have 2 identical knife copies in any super steel, and too cheap to do that.

ETA: Slightly off-topic but worth noting as it impacts the posted results. Taking good pics of edges is hard! Dang, it takes like 20 photos from different angles to get a pic that even halfway looks like the finished edge does in person, and even then, it really doesn't. Wish I could figure out a better way to do that which doesn't take so much time. Maybe the irregular, shiny surface of an edge with its scratches, etc., is just reflecting light in all different directions, making it hard without a specialized lens or clever camera techniques to compensate for that and get an edge pic that looks something close to what it looks like to the naked eye.

 

[jc57]

It would be interesting to see how well that Sharp Pebble works with D2. I had a lot of trouble with D2 until I tried a silicon carbide oil stone.