Introduction: Tesla Turbine From Old Hard Drives and Minimal Tools

Build a Tesla turbine from 2 old computer hard disk drives using basic hand tools and a pillar drill. No metal lathe or other expensive fabrication machinery is required and you only need some basic craft skills. It's crude, but this thing can scream!



Tesla Turbines promise up to 92% efficiency of converting air or fluid flow to rotational energy and its use can also be inverted for use as a pump with exceptionally high efficiency too. With compressed air becoming recognised as a feasible form of energy storage, we can see this device in everyday life soon as a source of locomotion. Factoring the simplicity, robustness and resillience to ingress of this design and you have something ideal for pumping heterogenous fluids like sewarage or fluids with suspended particulate. As a pump, this device has an important role to play in the developing world. More about it here: http://en.wikipedia.org/wiki/Tesla_turbine

Step 1: Tools That You Will Need

1. Torx set of screwdrivers to disassemble the hard drives and to build the rotor
2. Circle cutter - get this from you stationary shop for 1.99
3. Engineering Compass - optional, you can use the circle cutter to mark the workpieces
4. Sheet-metal drill bit and a 5 mm drill bit
5. Half-round file
6. Hole file
7. Craft glue or hot-melt glue
8. Epoxy glue to bond aluminium (that's aluminum to you lot in the US/Canada!)
9. Gaffa/Bodge/Duct/Electrical tape
10. Hacksaw with metal blade to cut aluminium (see proper pronounciation in item 8)
11. Pillar drill
12. Compressor to supply the air to drive the turbine. You can also use a drinking straw and blow really hard 'till your eyes pop out.
13. Some spare hard disk platters (chances are that you will have a couple of attempts to cut the right shape of slots in them)

Step 2: Materials That You Will Need

1. Two hard drives.
2. Erm... that's it.

Step 3: Disassemble the Hard Drives

You will most certainly need the Torx screwdrivers to this. Remember that there also screws under the label, sometimes just one, mostly two.

The magnets and the armature assembly needs to be removed. Often, the top magnet is not screwed on at all but held on using (you'll never guess!) its own magenetism. Strip the hard drive right down - you should have a between 2 to 4 disks per hard drive.

Step 4: Build the Casing

With the 2 hard drive cases, use the bhack saw to cut each one in two so that when the parts are joined together they form a circular casing in which the hard drive motor can be mounted.

Cut along the red lines indicated on the pictures and start by making the larger half first - that way, if you bollocks it up, you can use this bit for the smaller half and reattempt to make the larger half from the second hard drive.

Then assemble with two halves with epoxy glue, making sure that you can spin a disk platter inside the newly-formed circular enclosure without it touching the sides. Clamp it and let the epoxy glue cure.

While you about with the epoxy glue, fill any gaps on the side with it to prevent air leakage and to reduce turbulance.

Form an air nozzles into the circular enclosure where the air filter is and drill a 5mm hole where the air inlet is going to be (see last picture)

Step 5: The Back Plate

The back of the disk drive enclusure may be stepped and the drive motor will probably have a step in its shaft too. The solution is to glue a stationary back plate in the casing over the motor.

Enlarge the hole in one of your platters to fit around the step in the motor shaft.
Mount the hard drive motor back in the glued-together casing. Glue the back plate in.

Step 6: Mark the Slots on the Rotors

This is the bit where craft and patience becomes important: It is imperative that the platters are kept flush during the cutting of the slots.

Use the circle-cutter or an engineer's compass to mark 3 circular slots on 4 platters. First, mark out 3 circles or 20mm, 25mm and 30mm radius. Then devide the middle (25mm) circle into 6 equal parts using the compass (set to 25mm if you did not do this while being bored in geometry class).

You now have the 6 drilling points where you will make 10mm holes using the sheet metal drill.

Step 7: Make the Slots on the Rotors

Drill the 6 marked holes on each of the 4 disk platters with a sheet metal drill bit. Do not use a steel drill as you will twist your disk when the bit binds to the thin sheet metal.

Join the holes up so that you form 3 equal slots using a hole file. Finish each curved slot off with a half-round file. Mount the disk in a wooden-clad vice and work as close as possible to the lip of the vice. Be careful not to bend the work piece.

Step 8: Make Disk Spacers

There is a fair bit of interesting math and physics involved which determines how far the disks need to be spaced. Since we are just prototyping here, it is sufficient that the disks are spaced by 2 thicknesses of the average postcard (how scientific is this? Well, that's what the formulas indicate).

So, using the hole cutter, cut at least 12 washers with inner radius 15mm and outter radius of 20mm.

Step 9: Assemble the Rotor

Start by stacking one standard, unslotted disk on the rotor.
Continue the assembly by stacking:
2 paper disk spacers on the rotor shaft.
Then stack slotted disk #1
...2 paper disk spacers
...Slotted disk #2
...2 paper disk spacers
...Slotted disk #3
...2 paper disk spacers.
...Slotted disk #4

Finally, add 2 or more paper disk spacers so that when the disk retaining ring is screwed back on, it will compress the disks so that they won't be able to slide past each other.

Align the slots on the disk with a pencil before tightening the retaining ring.

Step 10: Put a Roof on It!

Cut the top blanking plate from one of the recycled disk drives to the size of your turbine assembly. Make a hole in the middle so that it alligns with the slots when mounted.

Tape the whole thing together using duct tape or whatever tape you have on hand

Step 11: Test It!

Remember that hole you drilled in the side near the beginning of this project? You have probably coverd it up with duct tape. Find the and cut the coverting tape away. Stick a drinking straw into it and blow! The turbine should turn. Slowly.

You will now probably want to hear this thing sing like a canary: Apply a 80PSI air stream to the turbine for 10 seconds for it get up to speed and then listen to the beautiful sound. This one goes up to 22,000 RPM.

Then hold it in your hand and feel Carioli's forces.

Since the disk drive motor is a permanent magnet DC motor, you can also generate a current from it.

Comments

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jorge.coutinhodasilva.9 made it!(author)2015-08-06

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Homee2010 made it!(author)2015-08-02

Hey, nice build. I'm also a trombonist!!!!

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StephenC18 made it!(author)2015-07-28

So will this thing actually produce power? If so how much?

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gerrit_hoekstra made it!(author)2015-07-28

Yes it could. The power generated would be proportional to the efficacy of the turbine (depends how well it is designed and built) and that of the stepper motor of the hard drive (which you obviously would need to rectify to get a useful DC current). And of course the energy of the air that goes into it.

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nerd7473 made it!(author)2014-04-27

I attached a metal frame from the ps2 expansion bay to be a cover for the turbine. I also screwed the sides to it with original screws. The other day I had added wires to the back. I also tested it finally at 65-62 psi

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tealk made it!(author)2014-01-08

yoou could solder 2 wires to conntact on motor and start making electricity.(but with 22k rpm you will fry this motor i think)

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gerrit_hoekstra made it!(author)2014-01-09

it is a stepper motor with 4 outputs typically, so you will first need to run the 4 outputs into 4 diodes connected to a common positive rail. And as soon as you put a load on that output, the turbine will slow down. Frying will happen if the load's current requirement exceeds the current delivery capability of the motor/generator.

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nerd7473 made it!(author)2014-04-17

Could you link me to an article or provide a schematic on how to wire up the motor to generate energy from it... I have a HDD with three disks and I am planning on mounting the platters all together to get (hopefully) more speed... and I am planning on using an acrylic case...

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gerrit_hoekstra made it!(author)2014-04-17

This should do the trick for nearly all hard drive stepper motors and will cost less than 1£ / 1€ / 1$ / 1 clamshell / 10,000,000 Zimbabwean dollars:

https://www.instructables.com/id/Stepper-Motor-Gene...

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nerd7473 made it!(author)2014-04-19

I have a hose connected to my turbine but I need to know about how much psi at minimum do I need to run it? P.S. it is using three platters that are stacked one on top of another with the spacers at the top and bottom of the platters...

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gerrit_hoekstra made it!(author)2014-04-20

What the low threshold is before you get any rotation depends on many things. What is the practical value in knowing this in any case? Maybe just go ahead and blow air / water into it and measure it?

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nerd7473 made it!(author)2014-04-21

I don't have a air compressor...

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gerrit_hoekstra made it!(author)2014-04-22

It will just about turn if you blow really hard into it through a straw. But then again, I am a trombone player, so I have no problem doing this.

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nerd7473 made it!(author)2014-04-26

look at my turbine I added two springs on the hose to prevent it from kinking

temp_-550798387.jpg
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gerrit_hoekstra made it!(author)2014-04-27

Very cool!

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nerd7473 made it!(author)2014-04-26

I re-tested it and got it to run at 60 psi

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nerd7473 made it!(author)2014-04-24

going to test it today!!!

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nerd7473 made it!(author)2014-04-22

Hey I had a foot pump and clamped down on the tube going to my Tesla turbine so as to build up pressure and when I released it (close to 115 psi) and it spun a little.

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nerd7473 made it!(author)2014-04-21

I don't have a air compressor...

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DanTDM made it!(author)2014-01-31

I want hay! (I'm a horse)

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safwan.ndh made it!(author)2013-10-04

يسلموا شكرا لكم

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nerd7473 made it!(author)2012-09-07

I am building one

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tinker234 made it!(author)2012-02-21

wow could i use this to power a go cart

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Dyte made it!(author)2009-02-17

Very exciting stuff man. Do you think this system works under water? Also, how long do you estimate will an air bottle of say one liter last when constantly ejecting at 80PSI? A rough estimate is fine because I have no idea :)

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gerrit_hoekstra made it!(author)2009-02-17

I don't see any problem with an air-driven turbine running under water - I should try it, actually. There must be some clever applications for this? As for your second question - this depends on too many factors, espeically build accuracy. Bare in mind this thing was built in a woodworker's shop with nothing more than a pillar drill and a selection of files and a saw. You can either trial-and-error this to answer your question of go do a very interesting degree in mechanical engineering (!) and calculate it.

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Dyte made it!(author)2009-02-17

Yes well, my first idea when I read this was to use this as a lightweight engine for a lightweight boat... running on compressed air. That's why I was wondering if this was feasable; if I'd need 20 liters of compressed air to make it run for half an hour it would be a bad idea :-D. Any idea? Well I suppose the trial and error method is still the best road to follow here! Thanks!

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Mr.Clodex made it!(author)2009-04-26

So? The air would make the "Boat" float with displacement rules (Allowing you to glide across).

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itjstagame made it!(author)2012-01-15

I wonder if you used the original DC motor as a motor and turned this in to a pump, how much force you could get in air pressure.

Basically, if you used it as a pump you may be able to use a stream of air as propulsion instead.

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gerrit_hoekstra made it!(author)2012-01-16

All but the very oldest of hard drive motors are stepper motors and not DC motors. It takes a fair bit of circuitry to drive a 4-wire stepper motor, but the simplest solution is to just hack the original hard drive's PCB.

That's the wonderful thing with this invention by Tesla: it works very well both ways. So turning this into a pump will work.

author
Predator106 made it!(author)2011-06-18

I'm kind of stuck...I have at my disposal (at least what I want to use..) a 150 GiB WD Raptor hard disk and it has 2 platters built right into it (they're a bit smaller though..kind of unfortunate, but the spindle does spin at 10k RPM. So I imagine that will help me achieve what I am cooking up...could probably switch it out, into another enclosure if I wanted to though. not sure how well it would manage though...as in, if there's a big reason why that size of platter is used (perhaps that particular spindle can't handle it. though I suppose that's not really a showstopper).


Anyways, how can I tell if it's ceramic or metal without drilling into it? Is there a way to drill a ceramic plate successfully, without cracking or shearing?

In theory at least, the boundary effect would likely be a lot better with ceramic ones, too. That's because the old metal plate drive platters actually had an oxide coding (yes..rust) which..if you look at an electron microscope, is actually extremely bumpy/spikey vs slightly hilly (it's a huge difference, at that detail level).

So what hard disc drives have you used? The issue is that well..the drive I want to use is only about 2 years old. I'm not sure how "ancient" yours are though...

You say that some have ceramics, but not many that you've run into (iirc, that's what you said..maybe that was someone else ;) but which manufacturers..years, sizes, etc are these?

I wish there were a good way of being able to tell it, without cracking it. But I don't think e.g. a magnet would be a "test" of that sort of thing.

Thanks.

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Maxwell+Yun made it!(author)2011-12-05

That's weird. My hard drive platters were aluminum, and they were from 1999-2000. Weird how my platters were solid aluminum.

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gerrit_hoekstra made it!(author)2011-06-20

If the disk flexes in your hand, it is metal. If it snaps when you try to flex it, it is ...uhm... broken :-)

The surface effect is approximately the same over a perfectly smooth or a slightly textured surface - the drag force is applied well above the surface. We are not talking microscopic wind -vanes here, like in a pelton turbine! So ignore the point about the slightly rough iron oxide.

Besides, you will see that a metal hard disk platter is one of the most perfect surfaces you have ever seen - press two of them together and see how much effort is required to separate them.

author
Maxwell+Yun made it!(author)2011-12-05

Nice project! I am using this for my science fair project, and it is very useful! I have access to a CNC mill, so I modified your instructable:
1. I machined the hard drive case completely flat.
2. I placed an aluminum block on top and machined it to fit on top of the flat surface.
3. I placed a polycarbonate square on top as a covering.
Thanks for this awesome instructable!

I am from America.

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epicnoobpwn made it!(author)2011-12-05

Since I'm using an old (10 years old) hard drive, the walls of the turbine don't cover the top hard disks. I'm going to machine a wood enclosure out of wood and mount the motor on it. Basically a wood version of the hardrive casing.

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gerrit_hoekstra made it!(author)2011-12-05

Should look very nice when done. Post the pictures here!

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wildwabbit made it!(author)2011-11-06

Great project, a friend of mine is planing on making a slightly bigger steam driven tesla turbine, using parabolic mirrors to generate the steam.

I was intending to use this project as to have a play around with the porting, to see if there was an optimum or preferable set out, I am interested to know what happens when you off set the ports.

I spent half the day building this project and it took 30seconds with my air compressor for the hdd motor to internally disintegrate, I have not the slightest clue as to what the rpm's were but it was screaming, the momentum almost threw it out of my hand when the motor ceased. The shaft is jammed tight i could not get it to even slightly budge with a big pair of pliers.

Oh wel, l just have to find another motor with a long enough shaft, as the couple of spares that I have aren't long enough for the four disc and spacers.

Warning to others, don't get trigger happy with the compressed air, or your fun will be short lived.

Great project great results!!

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alvin9861 made it!(author)2010-06-10

I have started redesigning a auto turbocharger into a tesla turbine. The turbo is designed to handle up to 60k rpms and that makes it use perfect. I have built a larger turbine chamber to use 12 harddrive platters. I got an small sump pump to provide continous oil flow. I am using a 5 gal plastic bucket for the oil.

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Tomahawk92 made it!(author)2011-10-19

i wouldn't want to hook this up to the oil pump on a car. it pumps somewhat slow and when you start creating back pressure in your engine your going to cook the oil and destroy all the crank bearings. I was just thinking about adding one to a coolant hose. it doesn't destroy as much when there's back pressure and it pumps more liquid faster. if it slows down the coolant too much the car could over heat though.... but there is a temperature gauge on most cars so you should be able to tell when it has gone above normal. i am definitely trying this when i get some time. good luck.

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gerrit_hoekstra made it!(author)2010-06-10

Go!!

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zimzam93 made it!(author)2010-06-27

so is there anyway i can use this to charge my phone or something, or will it just spin and make a pretty noise, sorry im noew to this kind of thing

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doomsdayltd made it!(author)2011-08-01

really for this to generate electricity, the turbine needs to bee attached to an alternator to produce electricity.

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gerrit_hoekstra made it!(author)2011-08-01

The "alternator" in this case here is the motor in the disk drive.

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doomsdayltd made it!(author)2011-08-01

well er i'm just stuck with words right now, what i meant was connecting the turbine to an electric generator

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gerrit_hoekstra made it!(author)2011-08-01

You will need to extend the length of the rotating shaft to make a flange coupling to a generator. Some disk drives allow you to gently tap out the rotating shaft, so simply replace this with a longer shaft with a flange or universal joint - a piece of rubber tubing will do, I would think.

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doomsdayltd made it!(author)2011-08-01

thanks

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gerrit_hoekstra made it!(author)2010-06-28

See the other discussions on putting a rectifier on the terminals of the hard drive motor to generate electicity.

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gerrit_hoekstra made it!(author)2011-07-18

You won a medal for this? Well done! Your future as an engineer is secured!

I found a spreadsheet somewhere (and I don't know where it is now) that suggested that spacing should be about 0.8mm for something that has the viscosity of air. The more viscous the flowing material (water is more viscous than air) the bigger the spacing should be. It seems to not be too critical, but too tight and you loose energy from 'squeezing' your fluid through the gaps, and to loose and you loose energy from not sufficient fluid coming into 'contact' with the disk platters. My guess is that spacing is directly proportional to fluid viscosity (I do not know much about fluid mechanics).

The size of the inlet nozzle is of little importance - your aim is to get all the fluid to flow over the surfaces of all disk platters. I have a rectangular inlet that is a wide as the set if platters, which i made by simply sawing a cut into the one drive chassis, such that the airflow is directed along the outer tangent (i.e. 90degs to the radius line) of the platter. This way you will get maximum 'contact' between the energetic air and the platter surfaces.

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Slicerr2 made it!(author)2011-07-17

um i am doing a a science fair project this year with a friend and was wondering if you could give me the exact specifications to find out the spacing.

oh and by the way this years project is an extension of my project last year using your design it won me a bronze at nationals.

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Slicerr2 made it!(author)2011-07-17

oh and the sizing and angle calculations for the inlet nozzle would be great to

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Slicerr2 made it!(author)2011-02-15

why do you need to put the holes in the disks? the boundry layer effect should work without them shouldend it?

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Bio: At heart an engineer, musician, polyglot, cook, computer programmer, wood worker, brewer and hacker.
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