Big, Slow Rotary Machine Has Multiple Uses

A good majority of power tools in the average workshop are all about speed. Drills, grinders, and  sanders all whizz along at thousands of revolutions per minute. Sometimes though, you need to do things slowly. For that, [bongodrummer]’s big rotary machine build might be just up your alley.

The core of the build is an old washing machine, which supplies both the machine frame and its powerful universal motor. While this can be hooked directly to a power source and allowed to spin away, it’s far more useful with some speed control in place. For this, an Arduino is hooked up to a triac circuit with feedback, allowing the speed to be set just so for whatever operation you have in mind. A set of speed-reducing pulleys helps further for getting down into the double-digit RPM while maintaining smooth rotation. There’s even a timer for extended operation, with parts salvaged from an old microwave.

The machine is built with a large rotating platter on top. By placing a clean white screen on top, the platter is great for taking 360 degree photos of objects automatically. This could be of great use in a photogrammetry setup. Alternatively, by fitting a bowl and plough assembly, the machine can be used to mull green sand for casting purposes.

It’s a versatile build that could be used for anything that needs rotation in the vicinity of 50 rpm. You could even play vinyl records on it if you were so inclined. Of course, if you’ve built a record player out of an old washing machine, we’d certainly like to know about it.

15 thoughts on “Big, Slow Rotary Machine Has Multiple Uses

      1. Which reminds me.. I have been given a “1rpm” motor (through gear reduction) which gives me 250hp at the slow end. Now I just have to figure a good use for 250hp of torque at one rotation per minute!

        Ideas anyone?

        1. When you say “250hp” of torque at 1rpm, do you really mean 250hp? That would be 1790 Nm or nearly 1300lb.ft (or, in “Maker units” equivalent to a 254,000 oz-in stepper motor)

  1. Too bad that washer didn’t have a 3 phase electronic design. My old one does with of course perfect speed from tumble a wet pile straight up to near dry centrifuge. What often gives out on these washers is what you saved, when they get wet behind the “seal” it’s all over for those bearings. The spider is also a prime bust, also because of water. The one you saved must have failed elsewhere, I assume those parts got checked. Tip: keep your washer door open all the time it’s idle. Let it dry out.

    Anyone want to replicate this hack look for Sears or other brands that use ESC by means of 3 phase drive. One would need to either replace or hack into the ESC-timer-cycle board. There are 6 power FETs mounted at the edge the board. I would like to do something with mine the motor that is. The last time it ran it was loud as hell and banging the inside tub.

    The latest motors are direct drive, even better yet?

  2. Hmm, possibly good start for vertical axis wood lathe of all sorts of things though good bracing essential with some of microprocessor controlled tool moving cutter or even a movable rotary planer since they are dirt cheap from drills etc
    Watch your speeds for large masses with several bracing options for greatest stability and keep the kids away.
    Right now I take the multiphase brushless motors out of some washing machines to use as vertical axis wind turbines, some don’t even need the phases rewired, medium tech stuff all over the place for fun times…
    Thanks for post :-)

  3. Welding turntable. Either set up an armrest
    in a comfortable position so you can sit there and aim and pull the trigger while it’s rotating, or set up a bracket to hold the gun and do it that way. And probably put a steel plate on the turntable so you don’t burn it up.

    1. First thing I thought too, but you’ll need to do something about a ground, so the welding arc will fire. Also, once grounded, better if all the welding current (50 – 300A+) doesn’t flow right through the motor shaft and bearings, which demands some more thought put into the design.

      1. Maybe that board is insulation and you would put your welding clamp on the part, but every now and then, have to put it in reverse to unwind your ground cable. No?……Just kidding.

  4. Fun project hacking together different appliances components. Totally trying not to scope creep.

    For a ground plate… maybe ad a rotor type design with a lug to clamp to going to a big spring loaded spring steel if not beryllium copper contact(s), a ring maybe then conducting up to the top plate maybe? Would conductive grease be beneficial to prevent arching on the contacts if that was an issue? Trying to think how could rig with copper pipe hinged or something spring loaded too.

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