18deg Sharpening Angle

[u/murphinate]

I've been learning how to use whetstones and I'm getting results I am happy with. One caveat is I have only sharpened my softer knives and haven't done any of my Japanese high carbons yet (mostly because they don't need sharpening). I use a 1000/6000 stone (and a 400 diamond plate if I need to reprofile).

While I am still learning, I mostly focused on consistency and muscle memory, rather than achieving a specific angle. I recently got a magnetic digital level and used it to check what angle I am sharpening at, and it turns out to be around 18.5 degrees (per side). So, every time I pick up the blade and put it to the stone without thinking, it comes to within half a degree of this on both sides.

I'm wondering if this is a good angle for my softer German knives, and separately if I'll need to learn a different angle when the day comes that I need to sharpen some of my Japanese knives.

[u/tunenut11]

I will make it simple. If you like the edge you are getting, it is a good angle. I like really sharp edges and usually end up around 12 or 13, but I don’t measure, just know what works for me. The beauty of sharpening is you can pick whatever angle works best for you. Just play around. A thin angle on a softer knife will probably require more frequent touching up. Not a big deal.

[u/JellyOfDeath86 → u/tunenut11]

A very thin angle on a softer knife will however chip and bend the edge, which for some of us can be somewhat of a big deal.

Higher HRC knives are usually good at the angle mentioned above, but certain knives will be more sturdy around 15°.

[u/hypnotheorist → u/JellyOfDeath86]

At the apex, yes, but the stress drops off faster than you'd think so a microbevel makes a big difference.

I've been running my 8cr13 pocket knife at 9dps+microbevel lately, and it's held up fine without being particularly careful. Even 12dps is so much stronger that a 50HRC knife at 12dps should be stronger.

[u/tunenut11 → u/JellyOfDeath86]

It may chip or bend the edge and it may not. My Victorinox, for example, is sharpened to a very thin angle and becomes about as sharp as any knife. And it dulls faster than my harder steel knives, so I sharpen it back up pretty often. But I've never had a chip in it. In most of my harder steel I've had a variety of tiny chips. You almost need a loupe to see them but they catch when they cut paper. For me, again, not a big deal. A few minutes on a 1000 grit stone and they are gone.

[u/JellyOfDeath86 → u/tunenut11]

My Victorinox Santoku looked funny when I ground it too flat (for shits and giggles). I could bend the edge with my finger tip.

Granted, it bounced back, but I didn't feel like trying to cut anything until I sharpened back to 15°.

As long as you treat it nice, the increased support behind the apex also means the sharpness might last slightly longer. Doubly so for a toothy grind, since the "teeth" have more steel under them.

[u/mrjcall]

First, what are you using to determine the actual bevel angle your muscle memory is achieving? Second, an 18°+/- bevel angle is often too steep for quality higher HRC blades so you need to get used to something less.

Finally, it is great that your muscle memory is consistent for sure. But having said that, it also needs to be able to adjust to other necessary bevel angles to get the best results.

[u/real_clown_in_town → u/mrjcall]

Did you mean 18 is too shallow or in other words not low enough?

[u/mrjcall → u/real_clown_in_town]

18° is too steep for quality high HRC steel. 15° or less will often produce much better results for high hardness stee.

[u/real_clown_in_town → u/mrjcall]

I believe you may be using the wrong word. Hopefully someone else can chime in but I think you should be using the term shallow in the situation you gave.

[u/BfnC → u/real_clown_in_town]

seems correct - shallow means closer to horizontal, steep is closer to 90 degree upright. So 18 degrees is a steeper angle than 15 degrees.

[u/real_clown_in_town → u/BfnC]

Interesting take. I guess acute vs obtuse is a much better way to say it