Remix.run Logo
Remix clone Hacker News
new | show | ask | jobsGithub
▲ tptacek 11 hours ago

Elsewhere on the thread I pointed out that I'd noticed the video doesn't show anybody doing actual prep; making an easy but deliberate thin slice of a tomato is one thing, quickly dicing an onion or a bell pepper is a very different thing.

To that observation I'd add (h/t my Slack friends) this interesting site Seattle Ultrasonics stood up:

https://seattleultrasonics.com/pages/knife-database

One thing I notice here is that Japanese knives (and my trusty MAC) fare really well on the BESS and CATRA scale, but relatively poorly on the "Food Cutting Rank", which is based on an ad-hoc seeming performance scale of how well their robot fared with a bunch of cutting tests that included stuff like bread and cheese (h/t again Slack friends) --- which nobody uses a chef's knife to cut.

That's a weird scale to plot chef's knives across --- unless the purpose of building that scale was to showcase an electronic knife that does well on tasks people don't normally use chef's knives for, but maybe not as well on chef knife daily driver tasks.

▲condiment 9 hours ago | parent | next [-]

A talented chef might cut vegetables at 25hz, while the blade is moving at 44khz. So whatever cutting improvement is conferred by the ultrasonic tech will certainly be applied towards fast cutting. It seems that the main benefit for fast cutting would be that food doesn't stick to the blade.

I'll cut bread with my chef's knife (amazon shun knockoff) when I want to make less of a mess. One interesting thing I noticed is that when Scott was cutting bread in the video he was cutting a croissant and no crumbs fell.

It will be interesting to see the knife in the hands of real chefs. Two things I'm curious about are whether the ergonomics of the button are good, and whether the ultrasonic action atomizes foods as they're being cut, changing the experience of cooking in some way.

▲niccl 9 hours ago | parent | next [-]

I'd really like to see a citation for 25 Hz. It feels to me like a decimal point might be missing. And how does the knife moving at twice the frequency of the vegetables being cut work? do they do two complete cycles of the knife for every cut of the veges? that's not what I've seen watching cooking shows (which might not be the best thing to watch for this to be seen, of course)

▲tempestn 9 hours ago | parent | next [-]

Hz vs kHz. Your parent's point is that the knife is vibrating far faster than even the fastest chefs would be slicing.

▲oofbey 8 hours ago | parent | prev [-]

25 chops per second would be EXTRAORDINARY. Possible? Probably but only with super elite training. Most competent home chefs can probably do 5 Hz and probably struggle to get to 10 Hz.

▲mminer237 4 hours ago | parent | next [-]

The fastest button mashing record appears to be 16 Hz, so I definitely do not believe it is possible to chop with a knife in the double digits.

▲0xbadcafebee an hour ago | parent [-]

Can somebody count Jacques' garlic chopping speed then? Perhaps someone younger than 80 could do it faster? https://www.youtube.com/watch?v=H3ENOZgEqXg#t=1m20s

▲scythe 7 hours ago | parent | prev [-]

The sixteenth notes in "Crazy Train"[1] are nominally 552 per minute, or 9.2 Hz. Moving a knife at 10 Hz is probably very difficult. I would expect 2-3 Hz is a normal pace for a skilled knife user and 4-5 Hz is showing off.

1: https://youtube.com/watch?v=tMDFv5m18Pw#t=0m32s

▲superkuh 7 hours ago | parent [-]

Cerebellar oscillation (in the inferior olive) gate motor control interrupt speed and are generally limited to ~10 Hz in humans.

▲john_minsk 3 hours ago | parent [-]

That escalated quickly. Thank you!

▲mattmaroon 8 hours ago | parent | prev | next [-]

Damn, I was set to completely dismiss this as entirely useless overcomplication but making stuff not stick to the knife would be nice.

▲mckn1ght 7 hours ago | parent | next [-]

That’s where a lot of mess comes from, so I’m very interested in this tech. The worst are cucumbers, they stick to the blade and new slices pop them up and they roll everywhere. I get some better results by slightly angling the blade but it’s not perfect.

The blade quality doesn’t look great but I think any decent cook that knows how to hone will do just fine with it.

I’m not sure I’d spend the money and replace my expensive knives for a relatively rare edge case but it’s a neat innovation that might catch on elsewhere, or maybe they’ll make premium lines.

▲temp0826 5 hours ago | parent | next [-]

Maybe instead of building it into the knife, it needs to be something you could attach to any knife

▲john_minsk 3 hours ago | parent | next [-]

Interesting idea, but I would say that it is orders of magnitude harder compared to having an integrated system. Vibration in such a compact space with a very sharp blade... I want this system be stable around me.

I would say, if this idea becomes popular, knife producers can create their own versions in the new models, or retrofit old knives at the shop.

▲fooker 4 hours ago | parent | prev [-]

That's a pretty good idea.

If this was a small 40$ attachment you could put on the dull edge of any knife, this would be great.

▲dsr_ 4 hours ago | parent | prev | next [-]

Cucumbers: put your cutting board in a sheet pan. Now they roll away but stop at the rim.

Also works for helping with fluid containment.

▲masfuerte 5 hours ago | parent | prev | next [-]

I had a similar problem with spring onions. So I give them a lengthways slice first. The half moons don't roll.

▲bsder 3 hours ago | parent | prev | next [-]

> The worst are cucumbers, they stick to the blade

Is this issue possibly that amateur knives are too "polished"?

This doesn't seem to be a "professional chef" problem yet seems to be a significant "amateur chef" problem.

Is this simply the case that a knife with professional use takes enough dings and scratches that foods won't vacuum seal to the face of the knife?

▲tptacek 6 hours ago | parent | prev [-]

I mean, for both potatoes and cucumbers, I just use a v-slicer. $40.

The other weird thing about this is that neither a potato nor a cucumber demands an ultra-sharp knife.

▲SilverElfin 8 hours ago | parent | prev | next [-]

The video comparison of this knife cutting through potato compared to a regular one is very enticing. My own experience is that there is more sticking even on my knives that have those scooped out edges that are supposed to prevent sticking.

▲mattmaroon 6 hours ago | parent [-]

Yeah, those do reduce sticking, but they certainly don’t prevent it entirely.

▲andbberger 6 hours ago | parent | prev [-]

if you have a nice knife and cut by dragging the knife towards you with tip in contact with the board instead of cutting directly down, food will not stick

▲tptacek 9 hours ago | parent | prev | next [-]

I'm not saying it can't work, just that they didn't show it, and after the required thin-tomato-slice that's the thing I'd most want to see the knife doing.

▲knifemaster 9 hours ago | parent [-]

For reference it would be also nice to see your (and your Slack friends) knife handling skills.

▲tptacek 9 hours ago | parent [-]

Wh...why? I'm not selling anything. I'm just saying dicing an onion is a better test of a chef's knife than taking a single thin slice of a tomato. Seems like that's an argument you can just take on directly.

I don't think there's anything interesting about my onion dice. You'd be seeing a video of a banged up MAC, scraped up from all the times I've casually sharpened it in a hurry, doing the standard one-cross-cut Jacques Pepin onion dice. You know, an onion dice.

(The "Slack friend" thing was just that I felt bad about sharing a link I'd gotten just a few minutes while pretending as if I'd known about it myself. I have no idea their level of expertise! Probably better than mine though.)

▲knifemaster 8 hours ago | parent [-]

I was getting the impression that you are "selling" the fact that the performance of this knife is based on false advertising, and using personal anecodes and some anonymous people as a supporting argument. That's basically the only issue.

Aside from that, in my opinion dicing an onion is a much more simple task for a knife than taking a very thin slice of a tomato. And in both cases it is likely more about the technique/handling and the sharpening than the actual knife material or technology. But the average person does not care about those things, so this knife could at least in principle be something useful for them. Not for someone who is willing to invest some time in the aforementioned things though, like you (and me too, for that matter).

▲tptacek 8 hours ago | parent | next [-]

No I genuinely don't know if this is a useful product or not. I think it would be a more interesting world if it was, so I guess I'm rooting for it. But I've got those two indications that I should be wary: nobody really used the knife in the video, and he did that weird knife ranking that happens (in a weird way) to probably favor his new electronic knife.

▲jorvi 8 hours ago | parent | prev [-]

Well, I can't speak to "false advertising", but the thin slice he did with the tomato and the grape you can just achieve with a well-sharpened knife. Both sides of a whetstone and then a strop will get you there.

As for the sticking, this is solved by vertical fluting already.

Ultrasonic vibration is a complicated solution for a problem that has already been solved by the simple solution of just sharpening your knives. And you don't need to get expensive either. A Sharpal diamond stone, leather strop and a good workhorse knife like a Victorinox Santoku will get you there :)

▲tptacek 7 hours ago | parent [-]

He acknowledges you can do that with a well-sharpened knife. Of course you can do it with a well-sharpened knife. It's exactly the demo every single sharp knife does! His claim is that the ultrasonic knife will always do that cut, whether or not you assiduously keep it sharp, which is what I have to do with my MAC and Yuki to make it cut tomatoes like that.

But most chef-knife cutting isn't thin tomato slices, and you can always do that cut with a good thin serrated bread knife, too. I want to see it dice an onion. Seems like a small ask.

▲mckn1ght 7 hours ago | parent [-]

Yep, I have a Shun with micro serrations ([0]) that will slice a tomato so finely you basically feel no resistance.

The only downside is that you can’t really hone or sharpen it yourself so you have to baby it. I’ve had mine about 15 years and have sent it in one time for their free sharpening at about the 11 year mark. At least Shun blades hold their edge a really long time.

[0]: https://shun.kaiusa.com/classic-serrated-utility-6.html?srsl...

▲ 4 hours ago | parent | prev | next [-]
[deleted]
▲ 4 hours ago | parent | prev | next [-]
[deleted]
▲eightysixfour 6 hours ago | parent | prev [-]

> It will be interesting to see the knife in the hands of real chefs.

Not really? I feel like this is for the other people, the folks who don't have the training to use a chefs knife super well. I'd rather see a decent home cook compare it to their knife in general prep.

▲saxonww 7 hours ago | parent | prev | next [-]

The two things that stood out to me:

"The best tools shouldn't only be accessible to the pros" but his knife costs more than every knife in that database.

The weight is listed in their help articles as 330g. I also think that handle is chunkier than a typical high end chef's knife. It may be easier to cut things with it, but I think your hand and arm are going to get tired of using it more quickly than with a regular knife at ~100g less.

And I realize these fare worse than the high end japanese and german knives, but it's hard to get excited about a $400 knife you can't put in the dishwasher when you can get a perfectly credible fibrox knife for about a tenth of that, which doesn't require charging and can tolerate 'careless home cook' levels of abuse.

▲ackfoobar 6 hours ago | parent | next [-]

I don't think anyone who cares about the cutting experience would put a knife into a dishwasher.

▲saxonww 4 hours ago | parent [-]

I'm not disputing that, and it's kind of my point. Most home cooks (I would bet millions) are not worrying about "the cutting experience" when they are making dinner. They are using a knife to cut up vegetables or slice meat or whatever. Then they are putting that knife in the dishwasher. Not all of them, but most.

I think my other points matter more. I think people who are invested in the experience as you suggest care about more than just the edge and finish, they care about the weight and balance and feel as well. I think this knife is probably worse on those qualities.

I don't mean to say this knife sucks or that this guy is dumb. It's a cool knife, and he's clearly not dumb. I just think this is more a passion project curiosity kind of thing than a useful product addressing a large market need. Maybe a future mass market version (cheaper steel, stamped, more contoured handle) would change my mind.

▲ackfoobar 3 hours ago | parent [-]

> Most home cooks (I would bet millions) are not worrying about "the cutting experience"

Indeed, and they won't buy the knife at this price anyway. My point is that not being dishwasher-safe does not matter for ~everyone. If they care, they won't do it; if they don't, they won't buy it.

▲tptacek 6 hours ago | parent | prev [-]

Yeah the handle was the first thing I saw here that gave me pause. The handle shape matters a lot!

Though: do. not. put. your. $300. knife. in. the. dishwasher.

▲saxonww 4 hours ago | parent | next [-]

I felt the collective cringe from everyone reading that comment :).

▲CamperBob2 3 hours ago | parent | prev [-]

For those of us who aren't knowledgeable in this field, what happens if you do?

▲tptacek 3 hours ago | parent [-]

It's hard to do irreparable damage to the steel of a knife. It's just an inert lump of metal. But you could fuck up the handle. Theoretically, the detergent could dull your edge. If you don't isolate your knife and it rattles around, that'll definitely dull it. Mostly: it should only take a couple seconds to clean off your knife in the sink.

▲defrost 2 hours ago | parent [-]

> It's hard to do irreparable damage to the steel of a knife.

Sadly not impossible, I've 'lost' (they're still in the back of a drawer) two good knives to idiots attempting to pry apart frozen chops and steaks .. each case snapped a good inch from the tip.

Not damage from a dishwasher and not damage the edge I realize, but worth mention as a tale of caution.

▲Mtinie 8 hours ago | parent | prev | next [-]

I shared this with my tech friends:

“This has all the hallmarks of a product that’s going to be disappointing but I’m so optimistic it won’t be.”

I’m seriously hopefuls it works because vibroblades (I mean, “progressive knives” and “high frequency blade”) are awesome and the timelines of Neon Genesis Evangelion and Metal Gear are getting closer. Which may, or may not be a good thing.

▲SilverElfin 8 hours ago | parent [-]

Well we know this tech works because there are already ultrasonic cutters in medical and industrial equipment. So it’s more about whether they implemented it well, rather than some new fundamental discovery.

▲john_minsk 3 hours ago | parent [-]

Is it realistic to have enough power in such a small form factor for this effect?

▲comfysocks 6 hours ago | parent | prev | next [-]

Feel free to correct me if I’m off base, but it doesn’t seem like the robot is actually slicing. Looks more like it’s just mashing the blade into the tomato. In this case I can see how the vibration can make up for the lack of slicing action. Ie sliding the blade across the tomato.

My question is: would there still be an improvement if they used a slicing action?

▲SilverElfin 11 hours ago | parent | prev | next [-]

I was surprised by that too. The Shun did surprisingly well in the real world test despite lower scores on the other two categories.

▲data-ottawa 2 hours ago | parent [-]

A slight tangent but I find sharpness tests often don’t represent the experience at the macro level, but it’s easily benchmarked and quantified.

As an example are tons of people pushing Feather or Astra or similar ultra sharp shaving razors. I bought a ton of sample packs the ones I liked the most were Kai, which are considered relatively dull, but have properties which make the overall experience better (I recall reading they’re thicker and vibrate less during cutting).

To me that makes this knife cutting benchmark more attractive than sharpness or retention, but I still have questions about technique used in the benchmarks, and how that affects knife performance (e.g. I would never try to cut bread by just pressing down as this move does).

▲montag 9 hours ago | parent | prev | next [-]

The nerdy sales pitch got me excited about a knife. Also, I have to wonder if the name is a deliberate nod to the Seattle Supersonics...

▲jfim 9 hours ago | parent | prev | next [-]

I can see why one would use a serrated knife to cut bread, but what knife would one use to cut cheese other than a chef's knife?

▲realityfactchex 5 hours ago | parent | next [-]

Jacques Pépin suggested at [0] "basically you need three knives":

  - a chopping knive, 9-12" depending on one's hand
  - a utility knife for slicing, about 6"
  - a paring knife, a cheaper ordinary one is fine
Of those, other than the chopping/chef's knife, I imagine that one could generally slice cheese with the utility knife (depending on the cheese, of course).

[0] https://youtu.be/nffGuGwCE3E?t=12

▲mgiampapa 9 hours ago | parent | prev | next [-]

A Santoku or other knife with scalloped sides do well. There are also in fact, cheese knifes, for cutting and serving that are popular for self service cheese boards. Wire is also popular for cutting large block cheeses.

▲rcpt 9 hours ago | parent | prev | next [-]

There are cheese knives that are either very high aspect or have a holes so nothing will stick.

▲tptacek 9 hours ago | parent | prev [-]

Ironically, the cheeses I would cut with a chef's knife are exactly the ones that aren't going to stick to the knife. The ones that get messy are just as easy to cut with a butter knife.

(Amusingly, butter is one of the demos in this video.)

▲neilv 9 hours ago | parent | prev | next [-]

Ginsu confused us about use cases.

https://www.youtube.com/watch?v=6wzULnlHr8w&t=25s

▲jaredhallen 4 hours ago | parent | prev | next [-]

Nobody uses a chef's knife to cut cheese?

▲KingMob 4 hours ago | parent [-]

Ahh, but now they could. No need for specialized cheese-cutting tools with this knife, presumably.

Ditto for bread knives.

▲CamperBob2 10 hours ago | parent | prev | next [-]

One obvious question is where on that list the product in question would fall.

▲cwong430 6 hours ago | parent | prev | next [-]

The lower the better on the Food Cutting Rank

▲tptacek 4 hours ago | parent [-]

Yes, I get how the scale works, just not why I should take that scale more seriously than sharpness x edge retention.

▲formerly_proven 10 hours ago | parent | prev | next [-]

My question for this product is entirely different: It's well-known that ultrasonic sound can still damage your hearing despite being inaudible or nearly so. Does this?

▲ReptileMan 10 hours ago | parent | prev [-]

The problems were even bigger than that - they tested factory sharpness and factory geometry that often are shit. And not thinning and sharpening them properly. Let alone that the steel on the factory edge has high chance to fatigued/softer than the rest.