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Would you consider testing one of those electric Fillet knives? I suspect they work similarly to the oscillating tool, by moving the blade back and forth or up and down. The ones I have seen take either regular Power tool batteries or an electric "station" with I assume adjustable speed/power. It could be interesting to see. Should also be easier to modify to take your own blades as they take larger blades, if you want to experiment.
I used to use a larger more powerful version when forming and cutting graphite prepreg composite materials while building AV8B Harriers back in the 80's. Blade life was the limiting factor. We had to change the blades ridiculously often. Maybe once every foot of half inch thick layup.
@@goncalovazpinto6261 it wouldn't cut a free hanging hair. And you definitely don't want it near your skin. If you're finger is even close to the cutting edge you'll feel like you're fingers are burning holding the material.
@@OUTDOORS55 I was thinking something like a gillette razor but ultrasonic. When you shave maybe the water or shaving cream might keep the temperature down. But I definitely wouldn't resist trying to shave some arm hairs with that cutter you have!😆
Turns out this tech does scale up to full-sized knives. Commercial ultrasonic food cutters are ubiquitous in cake factories, for instance. It doesn't take that much power to excite a larger blade because the blade doesnt move forwards and backwards like a reciprocating saw. The piezo stack pumps a pressure wave into the blade that causes the metal of the blade itself to expand and contract. Even steel (even knife steels). The key is operrating the blade at a resonant frequency so you add up successive, low-power waves into macro scale action. You can avchieve > 10 microns of displacement on an 8" steel blade with as little as 6 Watts! Uktrasonics are cool. And a nightmare to learn!
I think the difficulty in scaling this up lies in the ability to move the blade that fast, the extra mass and size might make that very difficult as it just acted as a mass damper. However, I wonder if we could get a sufficiently large transducer for a larger knife and just give'er in the name of science
My thought exactly. Even though it's not moving it very far, the power needed to move a sizeable knife blade at 20k Hertz has got to be considerable. If you tried to make it battery operated, you might end up with a pretty short battery life.
I got a feeling the blade mass / physical characteristics of a given blade play a significant role when vibrating it with ultrasonics. Think of resonance frequencies, i think there's a right frequency and power level to use a given blade.
Here's the thing: you're not moving the knife back and forth, you're creating a standing wave that causes the metal of the blade itself to expand and contract. For any single cycle, that takes a bunch of energy. But at resonance, the standing wave builds and you can excite a whole lot of blade with very low (
@@sheimend The resonance can definitely help out, but there are limitations since the friction against the blade will directly compete with the power input to each vibration. For an example using your case, if the friction ever generated more than 10W of heat, that would slow down the blade each oscillatory cycle and eventually either stop entirely or even out at exactly 10W of generated heat. I agree that resonance is a key part of this technology, but large transducers will still be very necessary, especially for tougher operations.
5:21 Kevlar is thermally conductive, which makes it fantastically resistant against abrasion compared to other plastics. The Kevlar fiber heats up along the entire length, instead of just a hotspot. Kevlar is strong for its weight, but the thermal conductivity is what makes Kevlar shine in resisting friction, abrasion, and melting.
I believe the knife works with a piezoelectric device, this device has electric and mechanical characteristics that, to enter a resonance state, it requires certain parameters met. For the mechanical side, mass of the vibrating object is key. Any deviation from this parameter would decrease performance. Keep posting cool stuff, man.
100% this. Its a similar thing with quartz watches, a quartz fork is filed down so that it will resonate at a particular frequency which is used to keep time. Here, they're adding a blade to the end and tuning the size/frequency so it will resonate. Change the blade size, you won't get resonance and it wont work.
One of the largest issues with ultrasonic knives is the blade, piezo, and other parts essentially have to be tuned. Well if the blade is heavier than a couple miligrams, or longer than a very small blade at least. This would mean your average 3" knife would run at 13 ish khz multiple and rely on the steel sort of bouncing in length. (This whole thing is kidna hard for my brain to render so i might have got the frequency significantly wrong idk) Then we have the issues of geometry and power. You will probably notice that most ultrasonic cutters have the blade angled about 45deg to the axis of the vibration. This improves the cutting by having half the energy from the ultrasonic movement going into nanoscopically pushing the blade into the material with the other half sliding the blade. (this probably also did not help your attempts) The power requirements themselves are not really the issue, a 3kw cutter for example should be entirely within the realm of possibility. The issue comes from the fact that a 3kw anything mechanical is going to generate a significant reaction force. In the case of vibrations, this means that the user will have to be isolated from the vibratory components rather significantly or suffer friction burns. (and therefore reaction masses are also required)
That was a bone edge of that drywall too. The hardest part of a sheet of drywall to cut through. Just throwing it out there while that thing was doing the work of a router/cut out with no dust, or at least not a lot of airborne dust which is a big deal when doing remodels.
Glad you showed us this tool - it is amazing for what it does! I can think of soo many things that I could have used this for that i struggled with or buggered up due to the difficulty of the location of the cuts, the shapes or materials being used, etc. I still will not get one though because of the price but perhaps one day ill have a bit more money that i could set for something like this.
Yes, and you can get piezoelectric transducers capable of handling hundreds or thousands of watts of power. I imagine there is a practical limit where the blade itself will melt or shatter and it might not be much more than this little knife already does.
@@OUTDOORS55 from what I could gather from the comments and his discussion is that it's a sorta hard engineering and tuning issue. He seemed to be trying to model/tune the natural frequency and mode of his holder and blade and when he was using it was complaining some parts of the edge were cutting better than others...haha. So it might be particularly difficult to get full longer blade edges vibe along their whole length in some useful way even with tons of energy as it seems to be weird mode shapes moving through the metal that are doing some of the magic rather than the whole blade moving in some fashion. And if that is some of what's going on to make it so effective even on stuff it's not literally melting from all the friction...there is some chance really interesting things are happening at the sharpened apex that would tend to have less stiffness and lower frequency first modes, with really weird modes at these higher frequencies. With these frequencies and tiny deflection levels not even clear if some mode that basically saws or more puts some wave shape on the apex line would be better? Might depend on material. Haha...all that to say your request for bigger/heavier cutting job tool might be a very interesting and difficult science and engineering effort...lol.
@@stormsj The trick to the balance issue is because it's a combination of factors, the thing you are trying to avoid is a standing wave in the blade. This is dictated by the speed of sound in the blade material in addition to the frequency of oscillation the longer the blade the lower the frequency (generally speaking more on that later) If you don't get it perfect basically one or more parts of the blade are not oscillating and basically a plain old knife. Below 20khz it's no longer ultrasonic and would make a terribly high pitched racket during operation. However... You can adjust the design of the blade to make this work. (How ultrasonic cake cutters work) Slots in the blade can mitigate this to a great degree. The tool he describes could be made but a specialty blade would be required which honestly isn't that big a deal, all the oscillating tools already have specialty blades.
I hate to bring it up, but I think there are two reasons that your larger blades didn't cut: The first is a _maybe_ . Maybe the orientation of the cutting edge needs to be exactly the same, which is dramatically different from what you tried. The second is a _for sure_ . The element doesn't have enough mass, energy, whatever you want to call it, to vibrate heavier stuff. In the case of the big knife, it's likely putting all the vibration in your hand when the blade has more inertia than the handle... So you would have to match the angle and the weight.
Yep, I don't think it's practical to build a tool with a blade much bigger than what it has. I think the size and the mass of the bigger transducer would negate the benefits of having such a tool.
Im an engineer and we got a similar product at work to go with our 3d printers and they work amazingly, and lets me change my printed prototype to check fitmets and things without having to print a whole new prototype. Excellent combo
I wonder if it has something to do with the blade vibrating at a certain harmonic of itself. I reckon thats why your other blades didn't work, because the blade didn't resonate correctly with the ociliations of the motor? meaning they just kinda flung about rather than having a consistant resonant ocilation, thats my guess anyways
A couple of points: - why is it moving so smoothly through the material? Yes, melting often plays a part, as is the sawing motion, but in addition to this, the friction of something at rest is higher than that of something that moves (which is why once your car starts slipping in a curve it is hard to get it under control), and since the blade vibrates, it is never at rest. And depending on the material, you may evaporate it and form a bit of a gas cushion around the blade. - Why didn't it work with other blades? Look up "sonotrode tuning". The system needs to be at a resonance frequency to work well. Potentially, the driver might also recognize that it's being overloaded and stop / reduce power. - Why does it generate heat? It's not just friction. If you put a blunt sonotrode on a piece of plastic and use a high enough power, it will melt. You can boil water with ultrasound. it's just generally slapping the material around a lot and thus adding energy. Especially with a knife, this is concentrated on a tiny area, so you can quickly reach rather high temperatures.
I work in industrial electronics and we use ultrasonic proximity sensors in a couple of places. When you put your finger in front of the sensor you can feel your skin warming. It's harmless but very neat to experience.
I completely agree! I'd buy a tool like that! I also wonder about a portable bandsaw version. Motor on each end might help with the power needed for a longer blade
Thanks for bringing this to light! I see a huge application in the 3d printing world as well would be so easy to clean up support areas or for joining parts. Same with the crafting/cosplay world especially considering the scale of the blade. I know so many people that burn through easily 200$ in razor/exacto blades on foam and other thin plastics. The only other tool for those is a hot wire cutter which...well has a lot of its own drawbacks especially. i had just discovered they make ceramic box cutters and that has already been a game changer but being able to dig into plastic opens a lot of possibilities.
For a bit to do holes in drywall you would want a thing metal rod like a needle to it could cut in any direction you should try a needle i am curious what it would do in that knife
I’ve put utility knife blades in vibrating saws for years & it works really well. Probably my favorite application is cutting carpet with a hooked blade in a vibrating saw. It makes a tough job easy peasy!
I've been wanting one for hobby use for ages. It'd be perfect for cutting models, cosplay (lots of foam and material), cutting open ultrasonic welds etc. I've heard they're the secret sauce for car detailing shops that need to "invisibly" cut car headlights open.
Mechanical patents and medical patents are good for 17 years. I think design patents are good for maybe 5 years, but can't remember. This gives the inventor time to establish their own market before every one else gets a shot at it. It may take a few more years before they are available. I do have one of the original Fein oscillating tools. Part of the reason it was so expensive was because Fein made it, and their quality is a step above every one else.
HECK YEAH. I wonder if this was because of my comments :D I wanted a video on these guys so bad! I'm broke but I too would love a ultrasonic utility blade, would make cutting cardboard simpler too if it didn't catch fire LOL
You're producing shear forces in microscopic fibers in cutting almost all the materials that we use in daily life. Microscopic shear forces would be more efficiently produced with microscopic sawing motion.
I have seen them in industrial applications that cut much larger materials ( What I won't say, I don't want to be sued for revealing trade secrets.). Ultrasonic cutters work extremely efficiently, but if the "horn" part that transfers the high-speed vibrations to the blade ever cracks your ears will experience pain.
This is just a guess: The reason why a larger blades won't work in this tool is due to the greater mass. The tool probably uses a very high speed motor or gear set with correspondingly very low torque. The greater inertia of a larger reciprocating mass is too much for the low torque motor to move. Of course, the manufacturer could use a larger, more powerful motor, but that would cause size and cost to go up, which seems to be the opposite intention for this tool. Again, just a wild guess here, I'm just a dumb mechanical engineer.
Honestly a pretty good guess, the motor is this case is most likely a piezo linear actuator though and there is more vibrational mode stuff here than normal mechanics. So the length is more the issue than the weight.
As a test for larger blades - perhaps start with a couple links of a snap-off blade, or half a utility blade, and then help the oscillation "start" by tapping it with a small metal rod. Kinda like the oscillation of tuning forks are started. The reason being that with the increase in mass perhaps the motor of the unit might be capable of maintaining the oscillation but not start it. Kinda like how a fan, a washing machine, or a pump, would have a capacitor large enough to give a starting "oomph" - without the capacitor it'll stall before anything happens, but if you remove the capacitor after the movement began it can keep going as long as the motor is running.
Get a fix angle system like a tsprof or the new kme and get extra clamps and make sure you clamp the full length of the blade for stability and you should be good
As a chef , I'd say go slow , go tender on the blade , as not to bend it as much . If you go for long slow strokes and you sharpen while pulling towards you instead of away , you should get a good result
ken onion work sharp, razor sharp blades in less than 5 minutes, even heavily damaged blades. the grit belts last a long time too. the german made ones are cheap and very durable.
Here's my experience, and I can't tell you why there is a difference. Ive used a Marttiini 7.5" fillet knife my entire life. Rapala bought out Marttiini. At some point I bought a new Rapala carbon copy(so I thought) of my old knife. It did not perform as well. Under inspection the new knife was flat ground. The old knife was convex. Since I owned a 1x30 harbor freight belt sander I reground the new knife convex. It then worked just as good as the old knife. Don't know why there is a difference, and maybe I was just so used to the way my old knife performed that I didn't like the change but convex is my suggestion. I had ran over my old knife long ago, crushed the handle and replaced it with a piece of hickory hammer handle, didn't bother me at all. So I am inclined to believe there is a fundamental difference between convex and flat ground when it comes to a fillet knife. Mullet,snook,redfish,sandperch,sheephead,grouper,amberjack,etc.
I think this would have some applications in textiles because it doesn't leave frayed edges. I think the furrent tech is limited by size. To create something more powerful it would have to be much more robust to not shake itself apart.
If you're serious about attempting to make one This Old Tony has a video on his attempt. Applied Science has on on an ultrasonic solder gun and Thought Emporium has one on an ultrasonic homogenizer for lab work. Mostly the same working principals and it all seems very fussy Just found another one by Lindsay Wilson that goes into the technical stuff
@@michaelsullivan8934 Resonance is the thing and most of the tuning has to be done by the particular shape/dimensions of the metal horn connecting the transducer making the vibrations and the tool you want to vibrate. (Take this with some salt. I'm not educated or experienced with this. I've just seen a few informative videos on the subject)
Very cool, it is one of those things if you have the right application for it, it would be worth the money for sure. Would love to see it Supersized :D
A saw blade has set on the teeth for a very good reason, allowing the blade clearance to pass through solid materials like wood. Making a knife blade oscillate doesn't in any way help. Up sizing will only exacerbate the problem. Knives are primarily for slicing from an edge so the waste can curl out of the way
I think the friction is what will cause issues. larger blade would create more friction and generate more heat. Im also no engineer, so i could easily be wrong
That's a powered "exacto" knife (precision cutter), made specifically for miniature work. I'm not sure if the technology can be scaled up to oscillating cutter size, but for drywall in particular there are better alternatives already on the market, derived from either a jigsaw or a router.
First i want to say, i love your channel! Second, I've come up with several actually cheap ways to do this. You likely have more tools, but piezoelectric transducers are cheap on Amazon for audio systems. The smaller ones handle high frequencies and would move the knife well. If the base of the knife was t shaped(vertical), you could use two identical transducers attached on opposite sides and feed the same exact signal to each but one flipped in polarity. This would double the strength as one would expand at exactly the same rate the other contracted. You would want a steel with very little flex to get the most out of it. A small amplifier and battery pack could make the whole thing handheld.
Interesting. As a rock enthusiast this might actually be a good fit for manually cleaning up all the extra stuff that can appear amongst amethyst crystals that chemicals can't really deal with. At least if the crystals can resist breaking themselves. Unfortunately, still a bit too expensive to try and experiment with out of curiosity. But good to know the price is coming down, will have to keep an eye out over the next few years.
Wonder how it would apply to things like cutting out pieces from scale model kits and miniatures. Usually you have to cut with snips and then file down the plastic stubs that inevitably get left on your model pieces.
Getting a 20kHz oscillation is in the piezoelectric range, like a quartz wristwatch. If this is the material they used it would explain why other blades didn't work, it's tuned to resonate with a particular size and shape of blade. I doubt they can make one at the size you're after in a portable form, though I'm no expert.
Yes this is true. I didn't mention the resonance tuning since i have no way to alter the frequency. I believe the much higher price units have the ability to tune the frequency to get the correct tuning for different blades. But that about as far as my knowledge goes 🙂👍
This is a bit off topic, but if you get a large, well made/designed knife, like an esee junglas, busse bushwacker mistress, sykco alpha regulator, a rinaldi manaresso, etc, you can not only chop instantly through that Kevlar (in all likelihood), and kydex, and rubber, they are also able to slice and cut such materials because of the immense increase in leverage and weight. How is that relevant? Well, most people consider those knives TOO big or impractical, but the reality is they have vastly superior cutting capabilities that many of you likely do not explore.
Way off topic but I'm a fan of an anime called Evangelion and in it they have a weapon called the Progressive Knife. It's a (gigantic) knife where the blade has this exact function and I have always wanted a knife like it. Even a human sized version of the Progressive Knife is probably not yet obtainable but I digress, I need this tool in my collection, even though I have no need for it. Edit: Although now that I think about it I do a lot of plastic model building so this might actually come in handy for that since it works so well on plastic.
So basically, the Mass and size of the Blade is crucial for its ability to swing. The oscilator in the tool is only swinging at one specific frequency and amplitude, the Bigger and heavier blade just damps out the oscilation. Why it cuts so well is more or less obvious, so the Blade edge has a very high speed and it hits the surface like a chisel. The Friction is similar in both directions so it does not push the blade out. The oscilator is probably a Piezzo crystal which is very limited in Power output Those bigger tools work very similar but they have a lower frequency and higher amplitude according to their Blade inertia. The oscilator is usually a Motor with a Belt. If you force a heavy Hunting knife Blade onto them they wont work either.
In all situations, an edge cuts better when moving through two axis than one. As the motion of the piezoelectric moves the blade, its likely moving in two directions when moving at 40k cycles per second really quickly and then getting clear of the cut and repeating. All my longest chef knives stay sharp far longer than my steak knives (when I could still afford steak) even though they are decent. They spend more time scraping against the plates with more pressure
Great idea wonder if the heat increases with the size of the blade though. Have seen larger models in use but i don't think heat tests were ever done on them, i imagine it would be a matter of rising or lowering the frequency on a bigger blade to mitigate the heat problems but unsure of how the process works.
@@michaelsullivan8934Its actually pretty simple. Plastic get softer with heat, therefore it cut easier. You can do a fun little experiment in your kitchen. Take a frozen dice of butter and try to cut it with a cold steel knife and then you do the same with a hot steel knife. Please ask your parents before if your not a grown up or a eagle scout.
@youremybiggestfan good addition. The soldering iron of course only works for thermoplastics, not for any kind of resin like epoxy or many rubbery materials like silicone.
I wonder if it would be possible to rig up an electric toothbrush with an exacto blade 😂 definitely wouldn't work as well as a dedicated ultrasonic knife, but would it work at all? 🤷
Hello! Ultrasonic knives were used for more than a decade in medical applications. The ultrasonic blade doesn't cut through cells, it rather splits cells from each other. Now, You mentioned that the vibration generates heat - it's actually something You don't want, as it is a side effect of having blade shape and size not match the vibration frequency. The comment, that vibration generates heat through friction makes me think that the knife You used isn't actually ultrasonic. The blades (in medical ultrasonic knives) are not sharp, and they are equipped with a water spray.
@@LtKwasretaken That is true, the blade in a bone scalpel can heat up to 70 deg C - most of plastics need more to melt. I should point out, that the blade itself doesn't vibrate, that's not how it all works.
I don't know if my last comment sent, but i wonder if there's a certain resonance the blade has to have, I bet with a different ocilation frequency from the moter and a bigger blade could be made as long as they both resonated well with eachother, hmmm
I wonder what the blades are made out of. I feel like it would have to be extra hard due to all the tiny “cuts” it’s making. I also wonder if the blade gets hot
Could you try it on a piece of bathroom/kitchen tile. Ceramic or equivalent and let us know how it performs. Just curious if it can do it. Very small cuts of course. Like if you just needed to remove a couple Millimeters.
The blade probably vibrates at resonance, which is its natural vibration frequency. Another blade would only work if: 1) the new blade was still light enough for the motor to move it without failing, and 2) the resonance frequency of the new blade matches the originsl blade. I think there are tools to predict the resonance frequency of an object, but even a small deviation will make it not work. So better off measuring it. Touch the originsl vibrating blade to a replacement blade made by the company sitting loose on a table, and you'll probably hear the blade vibrate, but touch the original vibrating blade to another of your blades and the sound will be quieter than you expected. That would confirm that this is a blade vibrating at resonance.
The Blade has to be in tune with harmonics of the vibrations. So you can’t just put something in it and hope to work. So you have to multiply the blade length with the harmonic wavelength oft the piezo. May be!
the length of the blade changes the harmonic of the tool. thus, different lengths / masses of blades will not resonate with the tool and loose the cutting effect
I'm wondering whether a device that big can even be managed by your average person effectively. When it's small, the mass of the blade and its vibration frequency are pretty negligible compared to an adult-sized person. But that might not scale very well.
reminds me of the vibrablades in the star wars universe ultrasonic modules are dirt cheap on aliexpress, i wonder if something could be worked up on the cheap? i imagine the real magic is in the blade materiel.
hello, could you please do a video testing honing steels out again? id really like to see if honing towards your hand makes a difference. like holding the steel freehand and sharpend towards your hand. thats how i do it, and it can make your knife pretty sharp a few times before you need to actually re-sharpen. im curious if you sharpened, then dulled the knife, then honed the knife, and then stropped it, if you could get it back to insane sharp? or if the honing steel is too rough and damages the apex too much for the strop to fix. i can get my knife from feeling dull, back to sharp enough to pop hairs a couple times before the apex is too far gone. i know youve done testing already with them, but i really want to see if honing downwards and then stropping could refine the burr from honing or not. i suck at stropping, so im not the right person to test it haha
I have a nerd comment.on starwars, mandolorian series , they use a " vibroblade " . Its a large fighting knife , you can see the blade .it looks like a blur.
mandalorian vibro knife will one day be here lol i bet it woudl be useful just not to long because it can imagine hitting wire or tubing behind dry wall wayyyy to easy and boy woudl that be trouble.
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Would you consider testing one of those electric Fillet knives? I suspect they work similarly to the oscillating tool, by moving the blade back and forth or up and down. The ones I have seen take either regular Power tool batteries or an electric "station" with I assume adjustable speed/power. It could be interesting to see. Should also be easier to modify to take your own blades as they take larger blades, if you want to experiment.
Did you try shaving? That would be something! A shaving blade that doesn't chafe.
I used to use a larger more powerful version when forming and cutting graphite prepreg composite materials while building AV8B Harriers back in the 80's. Blade life was the limiting factor. We had to change the blades ridiculously often. Maybe once every foot of half inch thick layup.
@@goncalovazpinto6261 it wouldn't cut a free hanging hair. And you definitely don't want it near your skin. If you're finger is even close to the cutting edge you'll feel like you're fingers are burning holding the material.
@@OUTDOORS55 I was thinking something like a gillette razor but ultrasonic. When you shave maybe the water or shaving cream might keep the temperature down.
But I definitely wouldn't resist trying to shave some arm hairs with that cutter you have!😆
Turns out this tech does scale up to full-sized knives. Commercial ultrasonic food cutters are ubiquitous in cake factories, for instance. It doesn't take that much power to excite a larger blade because the blade doesnt move forwards and backwards like a reciprocating saw. The piezo stack pumps a pressure wave into the blade that causes the metal of the blade itself to expand and contract. Even steel (even knife steels). The key is operrating the blade at a resonant frequency so you add up successive, low-power waves into macro scale action. You can avchieve > 10 microns of displacement on an 8" steel blade with as little as 6 Watts!
Uktrasonics are cool. And a nightmare to learn!
Yes achieve clean cuts in cake and no sticking to the knife
Cool, thanks for the comment. Now knife hobbyists just need an adjustable vibrator.
I think the difficulty in scaling this up lies in the ability to move the blade that fast, the extra mass and size might make that very difficult as it just acted as a mass damper. However, I wonder if we could get a sufficiently large transducer for a larger knife and just give'er in the name of science
My thought exactly. Even though it's not moving it very far, the power needed to move a sizeable knife blade at 20k Hertz has got to be considerable. If you tried to make it battery operated, you might end up with a pretty short battery life.
I got a feeling the blade mass / physical characteristics of a given blade play a significant role when vibrating it with ultrasonics. Think of resonance frequencies, i think there's a right frequency and power level to use a given blade.
Here's the thing: you're not moving the knife back and forth, you're creating a standing wave that causes the metal of the blade itself to expand and contract. For any single cycle, that takes a bunch of energy. But at resonance, the standing wave builds and you can excite a whole lot of blade with very low (
@@sheimend The resonance can definitely help out, but there are limitations since the friction against the blade will directly compete with the power input to each vibration. For an example using your case, if the friction ever generated more than 10W of heat, that would slow down the blade each oscillatory cycle and eventually either stop entirely or even out at exactly 10W of generated heat. I agree that resonance is a key part of this technology, but large transducers will still be very necessary, especially for tougher operations.
I agree with everything said in here,
Outstanding macro camera work as always. ❤
5:21 Kevlar is thermally conductive, which makes it fantastically resistant against abrasion compared to other plastics. The Kevlar fiber heats up along the entire length, instead of just a hotspot. Kevlar is strong for its weight, but the thermal conductivity is what makes Kevlar shine in resisting friction, abrasion, and melting.
Ultrasonic scalpels are in widespread use for surgeries.
That's what I was wondering, is it self cauterizing? There are conventional heated scalpels that do this.
What about something like Cataract surgery?
I think that model building would be a perfect application for this.
Exactly my thought. If Adam Savage doesn’t have one of these, he will as soon as he finds out they exist.
Also might be useful for 3d printing people as a way to clean up/further refine projects.
I believe the knife works with a piezoelectric device, this device has electric and mechanical characteristics that, to enter a resonance state, it requires certain parameters met. For the mechanical side, mass of the vibrating object is key. Any deviation from this parameter would decrease performance.
Keep posting cool stuff, man.
This is the real answer
I agree. I comented the same before i saw someone already did.
100% this. Its a similar thing with quartz watches, a quartz fork is filed down so that it will resonate at a particular frequency which is used to keep time. Here, they're adding a blade to the end and tuning the size/frequency so it will resonate. Change the blade size, you won't get resonance and it wont work.
One of the largest issues with ultrasonic knives is the blade, piezo, and other parts essentially have to be tuned. Well if the blade is heavier than a couple miligrams, or longer than a very small blade at least. This would mean your average 3" knife would run at 13 ish khz multiple and rely on the steel sort of bouncing in length. (This whole thing is kidna hard for my brain to render so i might have got the frequency significantly wrong idk)
Then we have the issues of geometry and power.
You will probably notice that most ultrasonic cutters have the blade angled about 45deg to the axis of the vibration. This improves the cutting by having half the energy from the ultrasonic movement going into nanoscopically pushing the blade into the material with the other half sliding the blade. (this probably also did not help your attempts)
The power requirements themselves are not really the issue, a 3kw cutter for example should be entirely within the realm of possibility. The issue comes from the fact that a 3kw anything mechanical is going to generate a significant reaction force. In the case of vibrations, this means that the user will have to be isolated from the vibratory components rather significantly or suffer friction burns. (and therefore reaction masses are also required)
That was a bone edge of that drywall too. The hardest part of a sheet of drywall to cut through. Just throwing it out there while that thing was doing the work of a router/cut out with no dust, or at least not a lot of airborne dust which is a big deal when doing remodels.
Mounting a hook blade in an oscillating tool works awesome.
Glad you showed us this tool - it is amazing for what it does! I can think of soo many things that I could have used this for that i struggled with or buggered up due to the difficulty of the location of the cuts, the shapes or materials being used, etc.
I still will not get one though because of the price but perhaps one day ill have a bit more money that i could set for something like this.
This Old Tony made one out of an ultrasonic cleaner transducer 6 or so years ago.
Yes, and you can get piezoelectric transducers capable of handling hundreds or thousands of watts of power. I imagine there is a practical limit where the blade itself will melt or shatter and it might not be much more than this little knife already does.
@@stormsj i saw that video. It didn't look like he ever got it to work that well. Perhaps it's stil no powerful enough.🤷♂️
@@OUTDOORS55 from what I could gather from the comments and his discussion is that it's a sorta hard engineering and tuning issue. He seemed to be trying to model/tune the natural frequency and mode of his holder and blade and when he was using it was complaining some parts of the edge were cutting better than others...haha. So it might be particularly difficult to get full longer blade edges vibe along their whole length in some useful way even with tons of energy as it seems to be weird mode shapes moving through the metal that are doing some of the magic rather than the whole blade moving in some fashion. And if that is some of what's going on to make it so effective even on stuff it's not literally melting from all the friction...there is some chance really interesting things are happening at the sharpened apex that would tend to have less stiffness and lower frequency first modes, with really weird modes at these higher frequencies. With these frequencies and tiny deflection levels not even clear if some mode that basically saws or more puts some wave shape on the apex line would be better? Might depend on material.
Haha...all that to say your request for bigger/heavier cutting job tool might be a very interesting and difficult science and engineering effort...lol.
@@stormsj The trick to the balance issue is because it's a combination of factors, the thing you are trying to avoid is a standing wave in the blade. This is dictated by the speed of sound in the blade material in addition to the frequency of oscillation the longer the blade the lower the frequency (generally speaking more on that later)
If you don't get it perfect basically one or more parts of the blade are not oscillating and basically a plain old knife. Below 20khz it's no longer ultrasonic and would make a terribly high pitched racket during operation.
However... You can adjust the design of the blade to make this work. (How ultrasonic cake cutters work) Slots in the blade can mitigate this to a great degree. The tool he describes could be made but a specialty blade would be required which honestly isn't that big a deal, all the oscillating tools already have specialty blades.
I hate to bring it up, but I think there are two reasons that your larger blades didn't cut:
The first is a _maybe_ . Maybe the orientation of the cutting edge needs to be exactly the same, which is dramatically different from what you tried. The second is a _for sure_ . The element doesn't have enough mass, energy, whatever you want to call it, to vibrate heavier stuff. In the case of the big knife, it's likely putting all the vibration in your hand when the blade has more inertia than the handle...
So you would have to match the angle and the weight.
Yep, I don't think it's practical to build a tool with a blade much bigger than what it has. I think the size and the mass of the bigger transducer would negate the benefits of having such a tool.
Im an engineer and we got a similar product at work to go with our 3d printers and they work amazingly, and lets me change my printed prototype to check fitmets and things without having to print a whole new prototype. Excellent combo
I wonder if it has something to do with the blade vibrating at a certain harmonic of itself.
I reckon thats why your other blades didn't work, because the blade didn't resonate correctly with the ociliations of the motor? meaning they just kinda flung about rather than having a consistant resonant ocilation, thats my guess anyways
Its just to less power to move that much mass that fast.
fyi? there's no motor
@@-COBRA There is but it is piezoelectric motor instead of the more common type of motor
@@-COBRA Of course there is no „motor“, but this knife is not designed for a larger mass of the blade.
Higher mass equals changed resonant frequency.
A couple of points:
- why is it moving so smoothly through the material? Yes, melting often plays a part, as is the sawing motion, but in addition to this, the friction of something at rest is higher than that of something that moves (which is why once your car starts slipping in a curve it is hard to get it under control), and since the blade vibrates, it is never at rest. And depending on the material, you may evaporate it and form a bit of a gas cushion around the blade.
- Why didn't it work with other blades? Look up "sonotrode tuning". The system needs to be at a resonance frequency to work well. Potentially, the driver might also recognize that it's being overloaded and stop / reduce power.
- Why does it generate heat? It's not just friction. If you put a blunt sonotrode on a piece of plastic and use a high enough power, it will melt. You can boil water with ultrasound. it's just generally slapping the material around a lot and thus adding energy. Especially with a knife, this is concentrated on a tiny area, so you can quickly reach rather high temperatures.
I work in industrial electronics and we use ultrasonic proximity sensors in a couple of places. When you put your finger in front of the sensor you can feel your skin warming. It's harmless but very neat to experience.
I completely agree! I'd buy a tool like that! I also wonder about a portable bandsaw version. Motor on each end might help with the power needed for a longer blade
Thanks for bringing this to light! I see a huge application in the 3d printing world as well would be so easy to clean up support areas or for joining parts. Same with the crafting/cosplay world especially considering the scale of the blade. I know so many people that burn through easily 200$ in razor/exacto blades on foam and other thin plastics. The only other tool for those is a hot wire cutter which...well has a lot of its own drawbacks especially. i had just discovered they make ceramic box cutters and that has already been a game changer but being able to dig into plastic opens a lot of possibilities.
For a bit to do holes in drywall you would want a thing metal rod like a needle to it could cut in any direction you should try a needle i am curious what it would do in that knife
Like a needle sized diamond rod file to cut in any direction
I’ve put utility knife blades in vibrating saws for years & it works really well. Probably my favorite application is cutting carpet with a hooked blade in a vibrating saw. It makes a tough job easy peasy!
I've been wanting one for hobby use for ages. It'd be perfect for cutting models, cosplay (lots of foam and material), cutting open ultrasonic welds etc. I've heard they're the secret sauce for car detailing shops that need to "invisibly" cut car headlights open.
Soooo. Vibroblade from Star wars?
My first thought!
Right!
Seriously though 😂
My exact thought.
Xcom :)
One has to wonder if the vibration produces enough heat to burn wood etc, does it ruin the temper on the blade?
Mechanical patents and medical patents are good for 17 years. I think design patents are good for maybe 5 years, but can't remember. This gives the inventor time to establish their own market before every one else gets a shot at it. It may take a few more years before they are available. I do have one of the original Fein oscillating tools. Part of the reason it was so expensive was because Fein made it, and their quality is a step above every one else.
HECK YEAH. I wonder if this was because of my comments :D
I wanted a video on these guys so bad!
I'm broke but I too would love a ultrasonic utility blade, would make cutting cardboard simpler too if it didn't catch fire LOL
You're producing shear forces in microscopic fibers in cutting almost all the materials that we use in daily life. Microscopic shear forces would be more efficiently produced with microscopic sawing motion.
There you go again showing me something I didn’t know I needed!! I actually have a current project that would be perfect for that.
Will it work on egg shell? Some people will do some nice art with egg shell. Love the video.
I have seen them in industrial applications that cut much larger materials ( What I won't say, I don't want to be sued for revealing trade secrets.). Ultrasonic cutters work extremely efficiently, but if the "horn" part that transfers the high-speed vibrations to the blade ever cracks your ears will experience pain.
This is just a guess: The reason why a larger blades won't work in this tool is due to the greater mass. The tool probably uses a very high speed motor or gear set with correspondingly very low torque. The greater inertia of a larger reciprocating mass is too much for the low torque motor to move. Of course, the manufacturer could use a larger, more powerful motor, but that would cause size and cost to go up, which seems to be the opposite intention for this tool. Again, just a wild guess here, I'm just a dumb mechanical engineer.
Honestly a pretty good guess, the motor is this case is most likely a piezo linear actuator though and there is more vibrational mode stuff here than normal mechanics. So the length is more the issue than the weight.
As a test for larger blades - perhaps start with a couple links of a snap-off blade, or half a utility blade, and then help the oscillation "start" by tapping it with a small metal rod. Kinda like the oscillation of tuning forks are started.
The reason being that with the increase in mass perhaps the motor of the unit might be capable of maintaining the oscillation but not start it. Kinda like how a fan, a washing machine, or a pump, would have a capacitor large enough to give a starting "oomph" - without the capacitor it'll stall before anything happens, but if you remove the capacitor after the movement began it can keep going as long as the motor is running.
Is there anyway you could do a video on sharpening a fillet knife? That’s flexible that also has length.
Get a fix angle system like a tsprof or the new kme and get extra clamps and make sure you clamp the full length of the blade for stability and you should be good
As a chef , I'd say go slow , go tender on the blade , as not to bend it as much . If you go for long slow strokes and you sharpen while pulling towards you instead of away , you should get a good result
@@pledford9 just sharpen it like regular knife, but go slow, i almost cut off my fingertip while sharpening this type of knife.
ken onion work sharp, razor sharp blades in less than 5 minutes, even heavily damaged blades. the grit belts last a long time too. the german made ones are cheap and very durable.
Here's my experience, and I can't tell you why there is a difference. Ive used a Marttiini 7.5" fillet knife my entire life. Rapala bought out Marttiini. At some point I bought a new Rapala carbon copy(so I thought) of my old knife. It did not perform as well. Under inspection the new knife was flat ground. The old knife was convex. Since I owned a 1x30 harbor freight belt sander I reground the new knife convex. It then worked just as good as the old knife. Don't know why there is a difference, and maybe I was just so used to the way my old knife performed that I didn't like the change but convex is my suggestion. I had ran over my old knife long ago, crushed the handle and replaced it with a piece of hickory hammer handle, didn't bother me at all. So I am inclined to believe there is a fundamental difference between convex and flat ground when it comes to a fillet knife. Mullet,snook,redfish,sandperch,sheephead,grouper,amberjack,etc.
I think this would have some applications in textiles because it doesn't leave frayed edges. I think the furrent tech is limited by size. To create something more powerful it would have to be much more robust to not shake itself apart.
If you're serious about attempting to make one This Old Tony has a video on his attempt. Applied Science has on on an ultrasonic solder gun and Thought Emporium has one on an ultrasonic homogenizer for lab work.
Mostly the same working principals and it all seems very fussy
Just found another one by Lindsay Wilson that goes into the technical stuff
I'd imagine you have to tune it to the resonant frequency of the blade, but I might just be using science words to sound more photosynthesis.
@@michaelsullivan8934 Resonance is the thing and most of the tuning has to be done by the particular shape/dimensions of the metal horn connecting the transducer making the vibrations and the tool you want to vibrate.
(Take this with some salt. I'm not educated or experienced with this. I've just seen a few informative videos on the subject)
looks like perfect lil knife for cutting eva foam for cosplayers :D
Very cool, it is one of those things if you have the right application for it, it would be worth the money for sure. Would love to see it Supersized :D
A saw blade has set on the teeth for a very good reason, allowing the blade clearance to pass through solid materials like wood. Making a knife blade oscillate doesn't in any way help. Up sizing will only exacerbate the problem. Knives are primarily for slicing from an edge so the waste can curl out of the way
I think the friction is what will cause issues. larger blade would create more friction and generate more heat. Im also no engineer, so i could easily be wrong
Are we going to have ultrasonic REX6000 edc blades in out pockets in the future? or will the pocket light saber come first?
And dudes will still use them almost exclusively to open packages and envelopes. Folks will go beyond hair-whittling to hair-vaporizing edges.
That's a powered "exacto" knife (precision cutter), made specifically for miniature work. I'm not sure if the technology can be scaled up to oscillating cutter size, but for drywall in particular there are better alternatives already on the market, derived from either a jigsaw or a router.
increasing the mass of the blade requires more power to vibrate at the same rate
The blade reminds me of my X-acto tool.
I think you need a certain size/weight blade to hit the resonant frequency, which is why others didn’t work
My company uses a similar type of blade on GFM machines to cut Carbon Fiber patterns for layup. They have been in use for over 30 years.
3:02 it’s similar to a dremel torch with a knife/wedge attachment
First i want to say, i love your channel! Second, I've come up with several actually cheap ways to do this. You likely have more tools, but piezoelectric transducers are cheap on Amazon for audio systems. The smaller ones handle high frequencies and would move the knife well. If the base of the knife was t shaped(vertical), you could use two identical transducers attached on opposite sides and feed the same exact signal to each but one flipped in polarity. This would double the strength as one would expand at exactly the same rate the other contracted. You would want a steel with very little flex to get the most out of it. A small amplifier and battery pack could make the whole thing handheld.
This would allow you to adjust the intensity and frequency very easily.
Interesting. As a rock enthusiast this might actually be a good fit for manually cleaning up all the extra stuff that can appear amongst amethyst crystals that chemicals can't really deal with. At least if the crystals can resist breaking themselves. Unfortunately, still a bit too expensive to try and experiment with out of curiosity. But good to know the price is coming down, will have to keep an eye out over the next few years.
That looks cool for post processing 3d printed items!
Wonder how it would apply to things like cutting out pieces from scale model kits and miniatures. Usually you have to cut with snips and then file down the plastic stubs that inevitably get left on your model pieces.
I’m reminded of the HF Blade used by Raiden in the Metal Gear series. Now we need to scale it up and add some movie magic.
i think they have one for sale now that has a 4 inch blade.
Wonderful video and great idea man, i knew that thing a while ago and allways thought it would be awesome to scalate it even to a knife
While it is only a kickstarter at the moment, there is a full sized ultrasonic kitchen knife in the works. It's called the 369Sonic.
Yeah I’m pretty sure you’re right about the power limitations on blade size. It just can’t vibrate the heavier blade.
Getting a 20kHz oscillation is in the piezoelectric range, like a quartz wristwatch. If this is the material they used it would explain why other blades didn't work, it's tuned to resonate with a particular size and shape of blade. I doubt they can make one at the size you're after in a portable form, though I'm no expert.
Yes this is true. I didn't mention the resonance tuning since i have no way to alter the frequency. I believe the much higher price units have the ability to tune the frequency to get the correct tuning for different blades. But that about as far as my knowledge goes 🙂👍
I really like the multi tool for cutting drywall that is in place very low dust compared to a Sawzall
This is a bit off topic, but if you get a large, well made/designed knife, like an esee junglas, busse bushwacker mistress, sykco alpha regulator, a rinaldi manaresso, etc, you can not only chop instantly through that Kevlar (in all likelihood), and kydex, and rubber, they are also able to slice and cut such materials because of the immense increase in leverage and weight. How is that relevant? Well, most people consider those knives TOO big or impractical, but the reality is they have vastly superior cutting capabilities that many of you likely do not explore.
Interesting but, I have several Dremel tools with circular blades that do most of that. Nice video!
Way off topic but I'm a fan of an anime called Evangelion and in it they have a weapon called the Progressive Knife. It's a (gigantic) knife where the blade has this exact function and I have always wanted a knife like it. Even a human sized version of the Progressive Knife is probably not yet obtainable but I digress, I need this tool in my collection, even though I have no need for it. Edit: Although now that I think about it I do a lot of plastic model building so this might actually come in handy for that since it works so well on plastic.
So basically, the Mass and size of the Blade is crucial for its ability to swing. The oscilator in the tool is only swinging at one specific frequency and amplitude, the Bigger and heavier blade just damps out the oscilation. Why it cuts so well is more or less obvious, so the Blade edge has a very high speed and it hits the surface like a chisel. The Friction is similar in both directions so it does not push the blade out. The oscilator is probably a Piezzo crystal which is very limited in Power output
Those bigger tools work very similar but they have a lower frequency and higher amplitude according to their Blade inertia. The oscilator is usually a Motor with a Belt. If you force a heavy Hunting knife Blade onto them they wont work either.
good review and that does produce much less drywall dust, plus curved cuts!
I've never seen these before... Looks cool!
Frequency and harmonic.
Like metal fatigue in planes.
Interesting topic.
Piezoelectric handpieces are super cheap on Amazon for dental scalling. Might be more accessible for experimenting.
In all situations, an edge cuts better when moving through two axis than one. As the motion of the piezoelectric moves the blade, its likely moving in two directions when moving at 40k cycles per second really quickly and then getting clear of the cut and repeating. All my longest chef knives stay sharp far longer than my steak knives (when I could still afford steak) even though they are decent. They spend more time scraping against the plates with more pressure
Bravo excellent vid and super duper suggestions.. Would bet someone will jump on inventing your super tool soon! Love all of yr vids bro! Thx
Great idea wonder if the heat increases with the size of the blade though. Have seen larger models in use but i don't think heat tests were ever done on them, i imagine it would be a matter of rising or lowering the frequency on a bigger blade to mitigate the heat problems but unsure of how the process works.
The Feinmiester was the original, I believe. My grandfather had one that cost around $600 back in the 80’s maybe. Just like the Festool domino
For plastics, I mostly use a soldering iron with an extra set of tips. Quite cheap. Proper temp setting is a must.
I guess heating the metal is basically just vibrating it on a molecular level anyway.
@@michaelsullivan8934Its actually pretty simple. Plastic get softer with heat, therefore it cut easier.
You can do a fun little experiment in your kitchen.
Take a frozen dice of butter and try to cut it with a cold steel knife and then you do the same with a hot steel knife.
Please ask your parents before if your not a grown up or a eagle scout.
@youremybiggestfan good addition. The soldering iron of course only works for thermoplastics, not for any kind of resin like epoxy or many rubbery materials like silicone.
Is it really true you can't cut plastic like that with a non-ultrasonic knife? A mora in rex121 might, if that existed...
Wait a minute, if you try to sharpen the blade with the ultrasonic powered on, how would that differ from ordinary sharpening?
Wonder if I attach a blade to my Phillips Sonicare toothbrush, would it work the same?
In lapidary some use an ultrasonic drill to put holes in very hard stone jewelry. There priced about the same as this knife.
What kind of steel is the blade? I'm curious what it's wear resistance is.
I wonder if it would be possible to rig up an electric toothbrush with an exacto blade 😂 definitely wouldn't work as well as a dedicated ultrasonic knife, but would it work at all? 🤷
Do you have any tips on sharpening a convex ground blade? Or am i over thinking it.
Opening plastic packaging like batteries etc. Would be a godsend
Could you do a video on the microsharp ”sharpener” from global? Would be interesting to see what it actually do to the edge of knives.
Hello! Ultrasonic knives were used for more than a decade in medical applications. The ultrasonic blade doesn't cut through cells, it rather splits cells from each other. Now, You mentioned that the vibration generates heat - it's actually something You don't want, as it is a side effect of having blade shape and size not match the vibration frequency.
The comment, that vibration generates heat through friction makes me think that the knife You used isn't actually ultrasonic. The blades (in medical ultrasonic knives)
are not sharp, and they are equipped with a water spray.
You would only need a water spray if the blade were generating heat... You know, to cool it down.
@@LtKwasretaken That is true, the blade in a bone scalpel can heat up to 70 deg C - most of plastics need more to melt. I should point out, that the blade itself doesn't vibrate, that's not how it all works.
I don't know if my last comment sent, but i wonder if there's a certain resonance the blade has to have,
I bet with a different ocilation frequency from the moter and a bigger blade could be made as long as they both resonated well with eachother, hmmm
I wonder what the blades are made out of. I feel like it would have to be extra hard due to all the tiny “cuts” it’s making. I also wonder if the blade gets hot
Would it be the same as applying tons of pressure in a single point without the weight just with the oscillation.
seems like high density materials are where this shines.
Like to see you fit a blade to an old Sonicare Toof Brush. I've knocked a capped molar loose with one before.
Could you try it on a piece of bathroom/kitchen tile. Ceramic or equivalent and let us know how it performs. Just curious if it can do it. Very small cuts of course. Like if you just needed to remove a couple Millimeters.
I'm wondering if there's an advantage when the blade starts dulling...
The blade probably vibrates at resonance, which is its natural vibration frequency. Another blade would only work if: 1) the new blade was still light enough for the motor to move it without failing, and 2) the resonance frequency of the new blade matches the originsl blade. I think there are tools to predict the resonance frequency of an object, but even a small deviation will make it not work. So better off measuring it. Touch the originsl vibrating blade to a replacement blade made by the company sitting loose on a table, and you'll probably hear the blade vibrate, but touch the original vibrating blade to another of your blades and the sound will be quieter than you expected. That would confirm that this is a blade vibrating at resonance.
Without opening it up, i assume it's using a speaker to drive the blade using magnetism. If these things end up being even cheaper, i'm buying one.
More POWER baby!
The Blade has to be in tune with harmonics of the vibrations. So you can’t just put something in it and hope to work. So you have to multiply the blade length with the harmonic wavelength oft the piezo.
May be!
the length of the blade changes the harmonic of the tool. thus, different lengths / masses of blades will not resonate with the tool and loose the cutting effect
I'm wondering whether a device that big can even be managed by your average person effectively. When it's small, the mass of the blade and its vibration frequency are pretty negligible compared to an adult-sized person. But that might not scale very well.
fun fact hospitals have been using those multi tools since the 40s the original name of the tool is a cast saw lol
Keep up the good work. You're on the bleeding edge of sharpness.
reminds me of the vibrablades in the star wars universe
ultrasonic modules are dirt cheap on aliexpress, i wonder if something could be worked up on the cheap? i imagine the real magic is in the blade materiel.
hello, could you please do a video testing honing steels out again? id really like to see if honing towards your hand makes a difference. like holding the steel freehand and sharpend towards your hand. thats how i do it, and it can make your knife pretty sharp a few times before you need to actually re-sharpen. im curious if you sharpened, then dulled the knife, then honed the knife, and then stropped it, if you could get it back to insane sharp? or if the honing steel is too rough and damages the apex too much for the strop to fix. i can get my knife from feeling dull, back to sharp enough to pop hairs a couple times before the apex is too far gone. i know youve done testing already with them, but i really want to see if honing downwards and then stropping could refine the burr from honing or not. i suck at stropping, so im not the right person to test it haha
I want an ultrasonic Bowie knife!
I have a nerd comment.on starwars, mandolorian series , they use a " vibroblade " . Its a large fighting knife , you can see the blade .it looks like a blur.
mandalorian vibro knife will one day be here lol i bet it woudl be useful just not to long because it can imagine hitting wire or tubing behind dry wall wayyyy to easy and boy woudl that be trouble.