Sanity check

[spoovy]

Hello all.

I bought my first high quality knife about a month ago, a Gihei blue #2 210mm gyuto. I've a question re sharpening if anyone can help. If I'm using the wrong terminology below please correct me.

The grind is a single-stage bevel, both sides, starting quite high up the blade (about 20mm from the edge, at the heel). It forms a single large 'V' shape looking at the choil. This means that when sharpening it (freehand) I can very easily match the exact angle of the grind by pressing lightly on the bottom third of the blade (near the edge). A couple of passes on either side on a 4k grit water stone brought it back to razor sharp and left fine scratch marks confirming the stone had contacted over the whole ground area.

So my question is, am I missing something here, or doing something wrong sharpening in this way? I ask because I was led to believe that sharpening a quality japanese knife would be more difficult than my other knives (which typically have a bevel only 2mm or so wide) when in fact it seems to be a hell of a lot easier due to how easy it is to get the correct angle.

Thanks in advance.

 

[valgard]

If it is sharp and it holds I don't see why you would be worried. And cheap stainless knives are a lot harder to sharpen according to common knowledge around here and my own limited experience.

 

[foody518]

-are you getting a burr on each side then deburring it cleanly?
-is edge retention where you want it?

 

[LifeByA1000Cuts]

Unless the knife was zero ground from the beginning: "a few passes" on a 4k won't convert an existing primary bevel to a zero grind, unless it was a true microbevel* Are you sure it wasn't razor sharp from the beginning and just got stropped/honed by accident by something you did?

Is this the same type as the one offered at Chef drives to show?

*means: making the actual "bevel usually 2mm wide" near-microscopically tiny (or having an "usually 2mm wide" bevel and a microscopic, more obtuse one on top of that). Useful for many scenarios. I'll avoid the terms primary and secondary bevel since their use is so confused and confusing....

 

[spoovy]

Thanks for your replies. I also avoided the terms primary and secondary bevel for that reason. And yes it's the same one advertised on that site, though I didn't buy it from there, I got it from a Swedish website, using Google translate to communicate. Saved about 40% off the list price at the other place mentioned :biggrin:.

It was indeed razor sharp when I bought it, so much so I couldn't quite get my head around it to be honest; it felt more like holding a straight razor than a kitchen knife. I'm getting used to it now, although it does still seem like overkill for most foods if I'm honest. I've not used it a huge amount really since I bought it as I'm a home cook. It dulled just a bit over the month I've owned it -- just enough to justify having a go at sharpening it really.

Zero ground -- a new term to me but, having googled it, yes this is what it has -- a simple 'V' shape starting about halfway up the blade and running all the way to the edge.

I didn't get a burr no. On my other knives I sharpen until I can feel a burr, as that's the way I can tell I've removed material evenly from the bevel, but on this knife I just gave it a few passes and it clearly revealed fresh metal across the whole blade so I just did the other side too then stropped it. It's very easy to see that fresh steel has been revealed as it's a carbon steel core which gets quite discoloured with use.

I'm not really in a place to say if I'm happy with edge retention or not yet as I've little experience. I'll form an opinion on that over the next 6 months or so I expect.

 

[foody518]

Try for a session where you aim to feel the burr as that is a reliable way to make sure you've gotten fresh metal right at the very edge where it counts. And getting an even burr along the edge can indicate to you that you're taking off similar amounts of metal at different sections of the blade, not changing the profile unintentionally

 

[LifeByA1000Cuts]

I still suspect you thinned the knife and accidentally repaired an existing microbevel, zero ground (or close to it, or hamaguriba that might be mistaken for zero ground) out of the box sounds *really* uncommon with double bevel knives.

BTW, If you want to measure the angles and check whether you have an unexpected frontmost bevel, use the laser pointer and cardboard box method i described so often people are sick of hearing it...in short, stick knife into something, shine a WEAK laser into edge, measure angle of reflections relative to blade axis, and divide in half.

 

[spoovy]

Looking at the Wikipedia page for 'Grind' it's described as a 'Sabre grind'. This is definitely it, and it definitely arrived like this. I spent some time examining it to make sure there was no second-stage bevel before starting on the sharpening because I really expected there to be one. Unless of course it's so small it's undetectable to the human eye I spose. How small can they be?

Why is this zero ground / sabre grind so rare then?

Not sure I'm grasping your laser pointer method but I don't have one anyway!

 

[LifeByA1000Cuts]

"How small can they be?"

As small as you can get it with just a few pitched up strokes on the finishing stone - which is a not uncommon technique, and is what you would usually do with a knife like that. Let's see (draw draw scribble scribble...), even if it was a true sabre grind (last two thirds appx. dead flat), you'd get a 6-10 dps angle (very dependent on how long the bevel actually is. angle will be smaller if section is not flat!) at the spine. 10dps sounds reasonable but rather delicate on blue #2. 6dps sounds like "could be usable to a user that was aware of that edge, certainly far far away from a general purpose gyuto edge".

It could be that the maker choses to supply the knife zero ground and expects the user to set a front bevel to his liking...

 

[spoovy]

So after reading about microbevels I'm seeing your point. It could well be that there is one there, so small I couldn't see it, and my afforts at sharpening have just done enough to scratch up the main bevel and round off the microbevel.
Hmm. I think I'll try putting a microbevel (back) on as it would seem to suit my use case.

Glad I thought to start this thread, I knew I was missing somethingd nothing's ever that simple!

 

[spoovy]

Cross posted there by the look of it

 

[LifeByA1000Cuts]

You could try to use it zero ground - but by all means on a wood cutting board ...