Passaround - SylvainM - C-Grind Bunka

[SylvainM]

Hi all,

As this is now a couple of weeks I hang on this forum I realize how much skills there are around here. This sounds a great opportunity to get feedback on my work, as this is probably the best way to improve ! Therefore I'd like to organize a passaround.

This one will be restricted to EU members, and I'll organize a separate one for US members very soon, with a dedicated blade (most probably gyuto or nakiri), so I get even more feedbacks.

The knife is bunka typed, see specs below. I'm happy to get any feedback on any topic, with a small focus on food release if possible as I try to finetune my C-grind to get a good compromise between the cut and food release. Blade as been used only by myself for a bit of testing.


Knife specs :
- Bunka forged in 1.2442 steel, approx 63-64 HRC, honyaki
- C-grind, right handed
- 175x54 mm, 167 mm cutting edge
- 3.2 mm thick at the handle
- Weight 171 gramms
- Handle is ziricote with chestnut spacer

Rules :
- EU members only, accounts above 6 months
- Target is 10 participants, right handed only (because of the grind)
- 350 € value insurance shipping, any damage or loss will be the responsibility of the participants
- 1 week testing period, vegs and proteine alike but no bones please
- Moderate to advanced sharpening skills required : sharpening permitted if you are confident enough but only 1k and up, have a go at stropping first - this is to avoid the last participant to end up with a paring knife
- Feedback to be posted in this thread at the end of the testing along with at least one pic of the knife to assess its condition before next one gets it
- Blade will come back to me at the end of the PA to assess how it handled it, then I'll see what I do with it


Please post your interest in this thread along with your location (country and city) so I can organize things. The idea is to ship the knife to the first tester within the next few days.

 

[JayS20]

While I prefer bigger knives, I'm in.
Nice for you to offer that opportunity.
Location: Germany

 

[TeaThyme]

I‘m in! Very curious to try one if your knives. Thanks for lending out your creation!
Location: Switzerland

 

[Yoshi]

I know we are not part of the EU anymore, but would love to try it.

Location: UK

 

[SylvainM]

I know we are not part of the EU anymore, but would love to try it.

Location: UK

Ah ah by EU I meant this side of the Atlantic Ocean So unless there is any specific complexity with UK, you're in !

 

[benomatic42]

In if it makes sense, PM sent

 

[JayS20]

Custom duties might be the problem, same for Switzerland

 

[SylvainM]

Custom duties might be the problem, same for Switzerland

Yep thought about it although not sure how it would work with a PA as there is no invoice involved (so technically, no value). I believe you are quite used to PAs, maybe we can take that in PM once my list is set, if it's fine with you ?

 

[Martyfish]

I'm in if it works with timing and Easter holidays. Location Düsseldorf Germany.

 

[SylvainM]

Allright so for the moment we have 5 participants:
@JayS20
@TeaThyme
@Yoshi
@benomatic42
@Martyfish

Anyone else somewhere this side of the ocean ?

 

[Yoshi]

Are you guys interested?

@PeterL
@Chasingsharpness
@fatboylim
@Ok__mode_6953
@lakee
@mozg31337
@Seqmt
@Gshep91
@Giovanny Torres
@Kevo90 @Teetertank @nightslayer

 

[PeterL]

Are you guys interested?

@PeterL
@Chasingsharpness
@fatboylim
@Ok__mode_6953
@lakee
@mozg31337
@Seqmt
@Gshep91
@Giovanny Torres
@Kevo90 @Teetertank @nightslayer

Yeah I’d be interested in trying it if it’s going to be circulating around the UK

 

[OkayMode]

Are you guys interested?

@PeterL
@Chasingsharpness
@fatboylim
@Ok__mode_6953
@lakee
@mozg31337
@Seqmt
@Gshep91
@Giovanny Torres
@Kevo90 @Teetertank @nightslayer

I’m a lefty

Thanks for tagging me in though!

 

[fatboylim]

Are you guys interested?

@PeterL
@Chasingsharpness
@fatboylim
@Ok__mode_6953
@lakee
@mozg31337
@Seqmt
@Gshep91
@Giovanny Torres
@Kevo90 @Teetertank @nightslayer

Kind of you. I'm out of the assessing game so I will be of little help! I hope you receive great feedback!

 

[Gshep91]

Are you guys interested?

@PeterL
@Chasingsharpness
@fatboylim
@Ok__mode_6953
@lakee
@mozg31337
@Seqmt
@Gshep91
@Giovanny Torres
@Kevo90 @Teetertank @nightslayer

If I wasn’t in the US I would lol

 

[SylvainM]

If I wasn’t in the US I would lol

I'll do one for the US soon, you may get in at that point

 

[SylvainM]

Hi all,
The knife got shipped this morning and is on its way to @JayS20 .
Then it will go (in order) to @Martyfish , @benomatic42 , @TeaThyme , @Yoshi and @PeterL .
Once Ben gets it in Netherlands I'll touch base with him to handle customs constraints for Switzerland and UK
Can't wait to get your reviews

 

[benomatic42]

Hey @JayS20 and @Martyfish , just curious whether this landed, or more relevant, is on its way to me. (I'll be gone for a few days so I wanted to check in just in case it would arrive in my absence, to make sure it gets held/routed correctly.)

 

[JayS20]

It's with me right no. Will send it to Marty next week when he's back

 

[Martyfish]

The knife arrived safely with me.

So here are my very initial impressions based upon a visual inspection and cutting a grand total of one onion and 4 chorizo, so don't take this as a comprehensive review.

The knife arrived with a stunning patina. I have no idea what @JayS20 cut up, but damn, it's beautiful.

It also has some lovely banding or something going on with the steel (see below).

The blade was very dull upon arrival (it showed absolutely no inclination to cut paper towel) and there were some very minor micro chips and what appears to be pitting in a small section of the blade. I gave the edge maybe 12 stops per side on a leather strop loaded with 1 micron diamond compound and that managed to bring the edge back to a usable sharpness. I was surprised it went from so dull to usably sharp in such a short amount of time, so it should be quick to sharpen and touch up. It would almost certainly benefit from some time on stones, but I'll have to find the time first.

I stropped the knife at around 15 degrees per side and the sharpened / polished area where the patina was removed was around twice as big as any of my other knives, indicating that it is thicker behind the edge than I am used to. To my eyes it also appears to be almost as thick at the tip as at the choil.

It did not glide through the onion quite as I am used to, I think mainly due to the lack of distal taper and thicker behind the edge grind, in addition to the less than perfect edge that I started with. I can imagine adding distal taper to a c-grind would be difficult, so the lack of distal taper is probably necessary and the thicker grind likely enables more low grind convexity to further promote food release, which I believe was the primary design goal here.

When dicing an onion, as far as my experience goes, the pieces of onion almost always ride up the blade until the spine, and this was no exception. I fully expect the c-grind to aid in food release when cutting other ingredients, but it didn't help much with a fine dice and I didn't really expect it to because small pieces of onion go where they are pushed and like to stick. The c-grind did seem to promote good food release when cutting up the chorizo - I find chorizo latches on to knives due to the high fat content, but some of the pieces fell off the blade unaided and the remainder were pushed of easily by subsequent cuts before reaching the spine.

I'll do a lot more cutting over the coming week and post a more comprehensive update.

Thanks @SylvainM for organising the passaround!

 

[Martyfish]

Introduction

I want to start off by saying that it has been an absolute pleasure to interact with @SylvainM during the passaround. He reached out to me via DM shortly before I received the knife and I have been updating him on my thoughts and impressions over the last week or so. Throughout these exchanges he has been extremely friendly, pleasant to interact with and receptive of all feedback, both positive and constructive in nature. Based upon this, I imagine that it would be a smooth and pleasant process to organize a custom knife with him. I also have the genuine feeling that he wants honest feedback, so that he can hone in on what knife enthusiasts value in a knife. A lot of things come down to personal preference in this hobby, but I suspect there will be a few common themes that will be shared by the passaround group, which hopefully enable him create knives that appeal to a higher percentage of the enthusiast crowd.

The Passaround Knife

Here are some photos of the knife:

Positive Feedback

I'll start off with the positive, the knife was designed with food release in mind and it certainly fulfils that design goal consistently, when cutting all manner of produce. Over the week or so that I had the knife, I made some direct comparisons between the passaround knife, a similar sized Yoshikane bunka and a Toyama nakiri, with the goal of comparing the food release and cutting performance of the 3 knives. I opted to use the Yoshikane bunka for the comparison, because it has a relatively similar size and shape to the passaround knife and therefore enables a pretty good comparison between the c-grind and a more traditional convex grind. I included the Toyama nakiri in the comparison because it is new and I wanted to see how it performed, but due to the different shapes and weights, it's far from a direct comparison. Near the end of my time with the passaround knife, I realised that I should have used my 140mm double fuller Newham nakiri for the comparison instead of the Toyama, because it's much more similar to the passaround knife with respect to size, weight and design, so I added the Newham in the last few videos. As mentioned above, the passaround knife consistently had the best food release of the 4 knives being compared. I filmed the vast majority of these comparative tests, so that anyone following this thread can see how the 4 knives perform and draw their own conclusions regarding both food release and cutting performance. All the videos, in addition to captions detailing my observations can be found in the link below.



It should also be mentioned that the knife was comfortable to use for the week that I had it. The handle was well proportioned, all of the surfaces on the blade that could potentially cause discomfort were rounded and I found the blade profile worked well.

Important Notes from the Videos

It should be noted that the first two videos in the above link (cutting tomatoes and cucumber) were filmed when the passaround knife was barely acceptably sharp. I received the knife in an extremely dull condition and managed to strop a bit of life back into it, but it was certainly not sharp. I went on to sharpen the passaround knife for subsequent videos, however I suspect that I did not do a very good job either at setting the apex or deburring, because the knife performed pretty sluggishly until I went on to give the knife another touch-up a few days after the initial sharpening. After the touch-up, the knife performed dramatically better and it genuinely felt like I was using a different knife, leading me to conclude that the cutting performance is very sensitive to the quality of the apex. I suspect the passaround knife needs to be kept very sharp to cut well due to the behind the edge thickness, which is greater than most high-end knives that I have had the chance to use. A lot of high-end knives continue to cut most things well (tomatoes and capsicum are the main exceptions for me), even when the apex is a bit dull, due to the extremely thin edge in addition to the thickness (or more accurately the lack of thickness) behind the edge. The passaround knife does not fall into this category, and the cutting performance appears to vary dramatically based upon the quality of the edge. I would be curious to hear if any other members of the passaround have the same experience here.

Geometry of the Featured Knives

Below are some choil and spine shots of the 4 knives used in the comparison, which should help to give a sense of the geometry of each knife. The order of the knives thought the photos is consistent, namely from left to right is the passaround knife, followed by the Yoshikane bunka, followed by the Toyama nakiri and closed out with the Newham nakiri. The heights and lengths of the knives all differ to some degree and I've tried to represent that in the collages, but the images are definitely not 100% to scale.

Constructive Feedback

Now on to the areas that I think could be improved - I'm all for fancy grinds, provided that they act to enhance the cutting performance of the knife or at a minimum offer performance roughly equivalent to a comparable convex grind. In the discussion of food release vs. cutting performance, it's usually a compromise between the two (as can be seen in the videos) and in this instance, I feel that the food release oriented design, while very successful in improving food release, sacrifices too much cutting performance to be worthwhile. That said, this all comes down to personal preference and what the end user values most, because the c-grind certainly aids in food release when cutting a wide variety of foods. There is a lot to like about this knife and I think I could make it suit my personal preferences after spending a few hours on the stones to reduce the behind the edge thickness and thin the tip a bit. If I were designing this knife from scratch I would also reduce the convexity on the left face of the knife to make it a bit thinner and reduce steering, because it doesn't really serve much of a purpose other than to keep the cross-sectional thickness within the c-grind high enough, and that could be done by reducing the depth of the c-grind. The asymmetry also made it a bit difficult to visually align the tip when making a cut, due to the lack of a firm visual reference, which lead to greater than normal inconsistency, especially when making vertical cuts in onions.

I think the knife could be greatly improved by reducing the behind the edge thickness, adding some distal taper and potentially varying the depth of the c-grind so that it is deeper at the heel and shallower at the tip or leaving it at a constant depth and terminating it 30-40mm from the tip. Please note that this analysis is brought to you by an armchair expert. It is always easy to suggest improvements, but what can seem like a simple suggestion can often be difficult to implement or create further unforeseen compromises, so @SylvainM, take these suggestions with a grain of salt.

Conclusion

Excellent food release at the expense of pure cutting performance with real potential for further tweaking and optimization.

 

[bermuda_chub]

These reviews have set the bar so ridiculously high that I’m embarrassed already, and the knife hasn’t even arrived yet. I’m probably better off just cut-and-pasting these into ChatGPT and enjoying the week pressure-free.

 

[Gshep91]

These reviews have set the bar so ridiculously high that I’m embarrassed already, and the knife hasn’t even arrived yet. I’m probably better off just cut-and-pasting these into ChatGPT and enjoying the week pressure-free.

This is knife. Knife cut good.

 

[benomatic42]

These reviews have set the bar so ridiculously high that I’m embarrassed already, and the knife hasn’t even arrived yet. I’m probably better off just cut-and-pasting these into ChatGPT and enjoying the week pressure-free.

% with you.

Between my uncertain sharpening skills and lack of comparison blades and experiences I've got little to ffer. I just received it this evening so it'll get a run this weekend, but we'll see how much I dare share

 

[benomatic42]

I went on to sharpen the passaround knife for subsequent videos, however I suspect that I did not do a very good job either at setting the apex or deburring, because the knife performed pretty sluggishly until I went on to give the knife another touch-up a few days after the initial sharpening. After the touch-up, the knife performed dramatically better and it genuinely felt like I was using a different knife, leading me to conclude that the cutting performance is very sensitive to the quality of the apex.

When did it get sharpened/touched-up, relative to the vids?

 

[TeaThyme]

thanks a lot for putting so much effort into your review! @Martyfish
Has the knife been sharpened since it reached the first person?

 

[Martyfish]

When did it get sharpened/touched-up, relative to the vids?

• Stropped on leather loaded with 1 micron diamond compound before the first video
• Sharpened before video 3, using a Naniwa Pro 800 to set the bevel and then a Naniwa Pro 3k to refine the bevel / deburr
• Touched-up before video 12 (the one with the eggplant) via few edge leading strokes on a Naniwa Pro 800 and then 3k

thanks a lot for putting so much effort into your review! @Martyfish
Has the knife been sharpened since it reached the first person?

I don't know if @JayS20 touched the edge during his time with the knife, but I stropped, sharpened and touched-up the edge as described above.

 

[JayS20]

I don't know if @JayS20 touched the edge during his time with the knife, but I stropped, sharpened and touched-up the edge as described above.

Came to me rusty, also at the edge, so got off the rust and then had to touch up the edge with a Nakayama. Was 4-layers TP cutting sharp after but this was at the beginning. Didn't touch it up again and did a bigger batch of Mire Poix before sending it off

 

[SylvainM]

Guys, no pressure ! Any feedback is a good feedback, even if less developed that those two we already got. Not anybody can be as precise as those two but that doesn't mean there is nothing to take from