3D-Printed Turbine Rotary Tool Tops 40,000 RPM

For your high speed, low torque needs, few things beat a rotary tool like a Dremel. The electric motor has its limits, though, they generally peak out at 35,000 rpm or so. Plus there’s the dust and the chips to deal with from whatever you’re Dremeling, so why not kill two birds with one stone and build a turbine-driven rotary tool attachment for your shop vac?

Another serious shortcoming of the electric Dremels that is addressed by [johnnyq90]’s 3D-printed turbine is the lack of that dentist’s office whine. His tool provides enough of that sound to trigger an attack of odontophobia as it tops out at 43,000 rpm. The turbine’s stator and rotors are 3D-printed, as is the body, inlet scoop, and adapter for the vacuum line. A shaft from an old rotary tool is reused, but a new one could be turned pretty easily. The video below shows the finished tool in action; there’ll no doubt be objections in the comments to ingesting dust, chips, and incandescent bits of metal, but our feeling is that the turbine will hold up to these challenges pretty well. Until it doesn’t, that is.

We like [johnnyq90]’s design style, which you may recall from his micro Tesla turbine or nitro-powered rotary tool. He sure likes things that spin fast.

38 thoughts on “3D-Printed Turbine Rotary Tool Tops 40,000 RPM

        1. I consider that a bad video because he says the corn starch in his experiment explodes, while in fact in his experiment it doesn’t. In science there are three ways for stuff to burn. Firs there is burning: like the candle. Then there is Conflagration (if I remember the term correctly) in which a flame front goes through the combustible material at subsonic speeds. And there is explosion where the flamefront goes super-sonic. The easy way to remember this is: explosions go bang. did you hear a bang?

          For real explosions to happen the air-fuel mixture has to be just-right. The allowed tolerance depends on the fuel. For grain-dust explosions to happen, the conditions have to be just right. But they do happen. If you try often enough, it will happen (by accident). Similarly, if you do this experiment often enough, you just might hit the conditions for the cornstarch to explode. Those conditions include not igniting the mixture immediately.

          1. Right ideas, wrong terms. Deflagration – subsonic, detonation- supersonic. Explosion – sudden and violent outburst. Both deflagration and detonation result in explosions, detonation is more violent and effective.

          2. Smouldering is a low-temperature version of combustion that usually happens without a flame, where the oxygen reacts directly with the surface of the fuel without vaporizing it first. Then comes regular combustion or deflagration, then detonation.

            Conflagration isn’t really a type of combustion. It just means a very large fire.

            Deflagration is the subsonic combustion of fuel in an rapid manner, where the heat eminating from the flame ignites the next layer of fuel. A candle flame is deflagrating, and gunpowder in a barrel is deflagrating – faster than the candle flame.

            >”In free-air deflagrations, there is a continuous variation in deflagration effects relative to the maximum flame velocity. When flame velocities are low, the effect of a deflagration is to release heat. Some authors use the term flash fire to describe these low-speed deflagrations. At flame velocities near the speed of sound, the energy released is in the form of pressure and the results resemble a detonation. Between these extremes, both heat and pressure are released.”

            Then detonation is where the combustion turns supersonic because the compression shockwave ignites the fuel throughout before the actual flame gets to spread.

          3. Detonation: there is no flame front or combustion as generally understood, the material decomposes ‘instantly’ to gas and heat as the explosion shockwave propagates through the material at the speed of sound for that material

          4. >at the speed of sound for that material

            No, the detonation shockwave exceeds the speed of sound.
            >”Detonation (from Latin detonare, meaning ‘to thunder down’) is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it.”

            Imagine a completely homogenous fuel-air mixture being slowly compressed inside a cylinder to the point of self-ignition. Since it’s equally mixed and compressed, it doesn’t take much to ignite it, and so a light shock or a flash of light (heat) may cause it to combust nearly simultaneously all over and the resulting shockwave exceeds the speed of sound. That’s detonation.

          5. Also there are more potent demonstrations that would be nowhere near as safe with his setup. My 8th grade teacher did a demo where stuck flour to the lid of a bucket with a candle in the bottom then whacked the lid with a ruler to dislodge the flour. It blew the lid off the can.

    1. Look at the video, it wants to stall almost immediately he touches the work…
      Also, the vacuum cleaner has 2kW INPUT power, this says nothing about motor or pump efficiency! You can get a “EU compliant” 900-ish W vacuum cleaner that works better then a chinesium 2kW one, all because it’s designed and built better.

      1. So much this! Ever noticed how much noise & heat is blasted out of most vacuum cleaners? Our current one is more efficient as a space heater than as a cleaning tool.

        I’m more impressed that he’s spinning 3D prints at 40krpm and nothing’s exploding, although I’m also curious how he’s keeping crud out of the bearings etc.

        1. But, very impressive build. 43k is pretty fast, I’m guessing those are more jab skate bearings.
          He’s also managed to get a lot more power than other vacuum attachments I’ve seen. I got a vacuum powered brush to use on our vac, and it span very fast but stalled as soon as it started doing any serious brushing, which made it kinda useless.

          1. Skate bearings aren’t actually engineered specifically for skateboard use; which is a very low RPM range. They’ll actually easily handle tens of thousands of RPM.

    2. Assuming that wood is something like pine, it looks to be similar power or slightly more than my £20 no-brand dremel knock-off.
      Which is considerably less than 100W!

  1. Very neat! I would be interested in seeing this on a CNC by creating suction using a stream of CO2. I forget the name of the effect but it should allow for something like this to work.

  2. This guy’s channel is really cool. Regardless of whether this thing works perfectly it looked fun to design and build. Once you have 250k subs on youtube your side hustle is as a video maker not a product inventor.

    The idea is really cool though, dremel has something similar but it doesn’t look like it would suck up the dust as well as this design. https://www.dremel.com/en_US/products/-/show-product/tools/vrt1-1-5-vacuum-powered-rotary-tool

  3. I’m not surprised that it works, as it looks to my uneducated eyes to be a fairly well designed turbine. I will, however, be surprised if it lasts very long operating at that speed. At some point it seems likely that one of the rotors will shred from the forces involved.
    Of course, he could always just print another one if that happens.

  4. The beauty of it is that while eventually all the ingested grit and fragments of cutting wheel and whatnot will wear out the turbine it is presumably cheap to replace and the vacuum will contain and clean up the bits when it fails, you’ll lose power, figure out why, pop in a replacement turbine and keep on trucking.. Plus. Yeah, it looks like a fun build and a good intuitive way to play with turbines.

  5. This is a nice bit of work. Regardless of the efficacy of the tool itself the 3D printed parts and housings are very clever and it’s amazing that you can build a rotary tool, essentially, out of plastic. It’s also amazing that it didn’t explode, but I can see with the amount of plastic on the outside of the blades where it’s pretty stout. It would be nice if an actual engineer chimed in on how to optimize the blades for greater efficiency.

  6. He could avoid surge-stalling by adding a small flywheel somewhere on the shaft (at the cost of slower initial acceleration).

    I’d also love to see this with a multi-stage turbine for more power… I wish I had a 3d printer!

  7. I assume he uses original shaft, bearings and probably not the rotor of the Dremel knock-off. He could leave the rotor on for mass and bump-out the airflow around the old rotor. The main point is he can just chuck up any mini tool bits, burrs etc. into the working end.

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