# Circular saw centrifuge

Start spinning more food in your kitchen than just salad. Bring the danger of the workshop into the kitchen with a homemade centrifuge! By using an electric circular saw as the motor, I was able to spin food up to 1800 G's and achieve separation in liquids, all for under \$20. This small capacity centrifuge gives a taste of what a centrifuge can do for your kitchen.

*Do not replicate this project, it is incredibly dangerous!!

How centrifuges work:
A centrifuge is a rotational platform around a fixed axis. Using the sedimentation principle the centripetal force causes separation of substances with different densities in a liquid.

This rotational force is measured in G's, where G is the measurement of gravitational acceleration felt as weight. On earth we experience 1G, roller coasters experience anywhere from 2-5 G's, and many fighter pilots can achieve 9G's. Since the amount of G's is inversely proportional to the radius of the rotation, smaller radii can achieve some staggering G's. It's not uncommon for lab centrifuges to reach 10,000G's.

Why centrifuge food?
Great question. Those into molecular gastronomy and your average food nerd love when cuisine gets a modern, technical twist. By using centripetal force you can separate food into layers based on density. In a liquid, this means denser substances like pulp are forced to the bottom while lighter substances like oils float to the top.

This means you can separate pulp from juice that might take hours in a fine-mesh strainer, like carrots or peas. You can even clarify things like broths to make them crystal clear. There's no end to the amount of foods that can be spun and remixed.

This Instructable will walk you through my journey to centrifuge glory. I had success, and failure. I will show you both. Though I was successful with my experiment you would be better off buying an inexpensive one if you are interested in trying this out, both for safety reasons and larger volume.

Here's how I made my centrifuge (or centrifood).

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ASCAS7 months ago

Dairk Laird7 months ago

Cool. When's the gas powered lawn mower engine version coming -lol.

gn0stik7 months ago

Get yourself a wall fader switch (the kind used for lights). That way you can turn it on gradually and avoid that initial shock to the system. If you have an RPM meter, you can put some black tape on your assembly, and measure the RPMs then mark it off on your fader switch so you know your RPMs for any given setting on the dial. Cheap, easy improvment.

wizodd07 months ago

The simplest food centrifuge is a lettuce spinner--a commonly used replacement in microbiology labs with low budgets. You don't need incredibly high speeds for a useful centrifuge.

But I'd still like one capable of dealing with larger volumes for extracting herbals...

vincent75207 months ago

Very nice, etc… etc… But why on earth would someone use a centrifugal force macine when cooking ???

What we need is how to combine ingredients, ie. blend them, not separate them, ie. "un-blend" them.

7 months ago

You can take fat out of non-low-fat salad dressings, or remove water from some food for whatever reason, and there's likely a bunch more you could you. Yes, a way to use a power tool to blend stuff would be cool, but I think this is cool too. It doesn't have to be just for food, either.

7 months ago

That it may be useful for other purposes than food I readily admit.

As for salade dressing, one can make his (her) own so he (she) won't worry about how much fat they put in manufactured dressing. Also home made dressing takes only 2 to 4 minutes to make at the most, and always tastes better than off the shelf stuff. Again taking water out of food is a good reason why to use such a contraption … but I'm afraid it would be difficult to pt salad leaves, or tomatoes or a steak in one of those glass tubes !!!…

Have a good week.

SpankyO7 months ago

Glass Cigar Tubes would work too... Just a thought

Commercial centrifuges are actually rather quiet. My guess is the saw housing provided more noise dampening than it would appear. Or maybe when we use the saw holding it absorbs the vibrations so the motor seems quieter.
Frostbite8507 months ago

I love your build!! It shows great ingenuity. Having worked on many styles and sizes of "fuges" during my career in the medical repair field, I have learned that it isn't always the imparted G's from rotation speed that does the separation. It is the separation angle and time at speed. That is why most medical fuges use pivoting tube carriers. That way they impart a 90% rotational separation angle. A blood separation fuge only turns at about 5k rpm yet separates 1 unit of blood (495gm) at a crack into plasma and platelets. two very important aspects are load balance and the addition of an upper shaft bearing to diminish wobble. Your cracked tube is the reason medical fuges use tube shields and cushions in the carriers. For non-medical use, a more reliable tube would be a food-grade plastic one. They are much tougher and pose less of a hazard if they do crack or shatter.

tovey7 months ago

If you used a drill press motor, you would not only be able to reduce the noise level, you would have better control over the specific RPMs.

The page you linked to shows that the centrifuge has an RPM of 3300. Your

4900 RPM motor may be just to fast for what you are trying to do.

mstreman7 months ago

FAIL--Sometimes wisdom lets you know just because you CAN doesn't always mean that you SHOULD. The cracked tube. wouldn't have happened if you had started level. else gimbaled the carrier .

I'm going to have nightmares of centrifuge failures tonight.

7 months ago

Not me!!!..... I am going to build several of these... VERY COOL....... I will sleep well...

LordBug7 months ago

Hey mate, just a little idea to offer to you.

To increase safety & stability, I'd build an arm with a bearing to goes over the top bowl. That'll soak up imbalanced loads, lengthen the life of the circular saw bearing, and remove a lot of risks.

Love the idea anyway!

Pyper707 months ago

Now hook it up to a Variac and limit the wattage to the circular saw....and spin it at a lower RPM. Good Job.

AlternateLives7 months ago

So, after reading this, I got to thinking...

Would it make this a safer build if there was some sort of kill-switch to shut down the machine if something went out of balance, like a pinball tilt sensor, thereby minimizing collateral/personal damage?

Or would it be too late at that point with these machines? I'm not very familiar with centrifuges.

seamster7 months ago

This has inspired me to go build something equally dangerous. I've got a crate full of 50s-era power tools just begging to have their guards removed and be tinkered with. Thanks!

7 months ago

That sounds like a good plan. Check out Rimar2000's projects for even more inspiration.

Bard7 months ago

My first thought is too bad you can't get the thing balanced like a car tire.

rimar20007 months ago

¡Capo! (and courageous)

kyle brinkerhoff7 months ago

we demand a video!

jmwells7 months ago
Commercial/lab units ARE much quieter. Most containment bowls are at least 1/4" thick, and the whole unit is spring vibration dampened. Great work as usual.
7 months ago

those types are also comprised of a solid carrier (like a flywheel), holes drilled down to leave about an inch of the tubes above the hole. I would imagine the circular saw would not reach as high a RPM as them, as they are mostly direct-driven motor-to-carrier. I would suggest a little more mechanical device for clamping the bowl halves together. Something like a set of C-Clamps (minimum 3, at 1/3 the circumference points), so that even flying shrapnel inside will not knock the top cover loose.

7 months ago
I've worked with them in food processing labs. The containment vessel is gaped such that it deflects everything downward, and inward. The direct drive is right though, except the very large ones. Large ships have centrifuges the size of cars for cleaning the fuel oil before it enters the turbines. They are combination gear driven and variable frequency drives. They spin at a paltry 3500 rpms. The fuel oil for ships is just above tar. It's full of sand and other debris. The centrifuge separates these from the oil.
pfred27 months ago

Most sidewinder circular saws have a gear box in them. I would check and see if yours does, and needs some grease. That could go some ways towards quieting your apparatus down. I have repacked a few saws and they do get quieter for the trouble. Most of the noise is likely from resonance of your wooden base, and bowls though. Still, reducing a bit of the vibration might offer some reduction in the noise level. Grease in gears is good for that.

sunshiine7 months ago

Thanks for sharing this Mike, I always learn something when you post an instructable.

sunshiine

hunter9997 months ago

Woah! This is a superb 'Ible...the immense amount of detail you go into is off the scale! Thanks so much for producing yet another awesome Instructable Mike. :D