Heavy Duty Lazy Susan for Full Body Scanning (Legacy Design)

by fredini Aug 23, 2012
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I could not access full instructions from this site. Would like to get full instructions as well as parts (chain length, motor, etc) list on how to build this new model with the chain.
I would like to leave you a nice tip for this. my email: tim@canyonprint.com

any idea what would be the best motor to use to turn 2 adults?

How did you mount the pulley to the motor? I understand that you need set screws to clamp the two together, but how exactly will that look?
~Inexperienced Mechanic

I've now released my 2.0 turntable designs http://www.thingiverse.com/thing:729923 which improve the drive mechanism with a chain drive,sprockets, and auto locking of the wheel with a Worm Gear Motor. I highly reccomend this version over the old pully based design.

In answer to the question, the shaft of the motor goes through the hole in the pulley and the set screw is tightened against the flat of the motor shaft.

Scan-O-Tron Turntable v.2.0 for Full Body 3D Scanning
by fredini

Update: The original rotisserie motor I bought and used, the one listed in the Make instructions (http://makezine.com/projects/guide-to-3d-printing-2014/heavy-duty-turntable/), turned out to not be powerful enough to turn 2 or 3 people easily. It would stall, especially if the load on the table was off center.

I searched around and found this motor: http://www.amazon.com/gp/product/B00858TNZC/

It turned out to work much better, with slightly higher ratings, and roughly the same RPM. It's not a massive improvement, but it's enough to avoid stalling most of the time. It took a while to arrive, mine came from China, but I think it's a much better first choice than the motor listed in the Make instructions.

I've now released my 2.0 turntable designs http://www.thingiverse.com/thing:729923 which improve the drive mechanism with a chain drive,sprockets, and auto locking of the wheel with a Worm Gear Motor.

Scan-O-Tron Turntable v.2.0 for Full Body 3D Scanning
by fredini

What size nut and bolt would be best to use to clamp the motor to the pulley? I am about to print the pulley but want to be prepared to mount it once finished.

Maybe an m-4, 25mm?

Hi Everyone,
Thank you for the turntable design.
I just bought a wheel hub on ebay and am about to start construction.
My wheel hub feels a little stiff and clunky when I spin it. My concern is that I will go to the trouble of making the turntable and it will remain jerky. Does anyone know if it is possible to loosen a wheel hub?

I'm interested in printing the pulley, however, the "native size" of the STL seems a bit large, especially compared to the picture. What should the correct diameter/height of the pulley be?

Thanks @KingRahl, @fredini. I ended up making the table top 34" in diameter and it seems to hold 3 people well. I just have the 2 layers of 3/4" wood glued together. I did spring for some nicer wood. I suppose it would have been good to have used some screws across the 2 layers. If I were to do it again, that's one thing I'd change.

Pictures of my build: http://dat.tumblr.com/post/94354097114/3d-scanning-platform-build-progress-pictures

I ended up having problems though with weight being off center, tilting the table a bit and with the added leverage from the wider table, and making it too much work for the rotisserie motor to turn the table. I'm in the process of fitting a 12V hand drill to a pulley now, which is plenty of power.

I'd like to have at least 2 people on the platform. What size diameter do you think the table surface can be extended beyond 28" and still be safe? Thanks for posting this design online BTW

Rahl is right, but as is, this design supports up to 3 adults.

The weight the platform can handle is dependent on the load capacity of the wheel hub, the strength of the wood, and your own construction capabilities. The hub is the strongest point. You need to look at the wood. All the support is coming from the center of the hub. As the weight is applied on the outside diameter, stress is created toward the center like a fulcrum. To overcome this you can do one or both...

  1. Strengthen the wood platform. The wider you make it, the thicker the wood will need to be. Or add thick enough plate steel to your structure to cover the entire turn plate.
  2. Support the outside circumference. I would suggest inverting caster wheels mounted to the base so the top turn plate rides on the wheels. Make sure they are evenly spaced around the turn plate. I would recommend using 6-8 casters.

Great design Fredini, thanks for sharing it, I have built one based on your design and just need to to add the motor. I have a 12v rotisserie motor from China but am wondering what kind of power supply to hook it up too, i.e how many watts will it need to turn up to 3 folk around? Look forward to seeing your brake design too.

What was your final solution to this? I have recently built the table and have all other parts, but not sure how to power the motor now. Emailed Fredini, but hoping you will see this message also.

Hi- Sorry for the delayed response. I use a motor like this http://www.ebay.com/itm/Electrical-Appliances-4RPM-Ouput-Speed-DC-Geared-Motor-/271243349319?pt=LH_DefaultDomain_0&hash=item3f275d0d47http://www.ebay.com/itm/Electr... with a standard 12v wall wart power transformer and a foot pedal to activate/deactivate the rotation. Hope this helps.

I was going to suggest using the turntable motor for braking by having a N.C. (normally closed) relay wired to it in order to short the motor leads together when the motor is deactivated. Should work for DC motors. But I think I am too late.....you already built the brake.

Go to Amazon, type in 'lazy susan bearing', do not pass go, do not collect $200,
Far more suitable 1000 pound 12" bearing for $16.25.

I totally disagree that that is better than my solution of the car hub. Uneven weight on the turntable would destroy those bearings. My solution allows up to four people to pose together with little concern for evenness of weight distribution.

About your Design..You can put Simple Wood break under the first spinning wheel..Pull and push mechanism..

Yes, I have added a brake- I need to update the project to reflect this. A simple foot pedal bar of wood on a hinge that applies pressure on the wheel from below as the subject climbs on and off. I will add some images ASAP.

I'd be interested in seeing those pictures from the brake you added, please.

Well its been awhile since you released this so have you got yourself the perfect RPM yet? If you would do everything over would you use 4 or 6 RPM? I'm building something like this for a school and I am about to purchase a 115volt gear motor for the project.

I'm at 3rpm and have a second rig underway that I have a 4rpm motor for. I'm thinking 6rpm may be too fast, but look forward to any feedback. I have added a brake pedal that applies pressure to the underside of the wheel as people climb on and off as well- need to update the project with this. For the 2.0 version I'm thinking that the underside should have a sprocket and a chain drive with a stepper motor. Looking into this now. please let me what you get for a motor and send me some pix.

Based on my experience, I'd say the optimal time is a 20 second rotation of the wheel. A scan can be completed in about 3 revolutions, maybe 4 if its a complex subject. The new design is now posted and has several improvements: http://www.thingiverse.com/thing:729923

Scan-O-Tron Turntable v.2.0 for Full Body 3D Scanning
by fredini

If you were to use a hub for a vehicle with ABS it would have machined teeth that you use with your solenoid for locking the rotation, just a thought

hello fredini! nice scans and scanner rig!
worm drives are auto-braking. also they are reductors, so could help with the torque too...

Can you recommend an affordable worm drive I should look at? I'm open to suggestions!

The 2.0 design of this thing uses a wormdrive motor,chain and sprockets: http://www.thingiverse.com/thing:729923

Scan-O-Tron Turntable v.2.0 for Full Body 3D Scanning
by fredini

Here is an idea, use the mcmaster style lazy susan bearing and mount high quality rollers or casters around the outside of the disk to keep it level and compensate for the small diameter of the McMaster bearing. The drive motor could be housed inside the base. Here are some screenshots from a rendering I just did of this idea. I have not tried to build it yet. The number of rollers would be based on their load rating. The wheel on the motor would be sized to generate the desired RPM of the stage based on motor speed and inside circumference of surface the drive wheel bears on. Foot petal or simple on off switch to control motor.

Here is a photo album on Google+, you should be able to see it with this link:


Do you think this would work?

I would consider this approach with a subsequent turntable, but my initial experiments with these bearings showed that they didn't do too well with uneven weight distribution. Using the bearing in the center and rollers on the sides is a better solution, but with a lot of weight on the rollers I just don't know how it would spin.

The beauty of the car tire hub is that it spins very easily even with a lot of weight.

Hi, I'm working on an update to the project and am looking for advice on a braking mechanism for the wheel when power is not applied to the motor. Any advice is appreciated!

I am considering some kind of retracting solenoid that could apply pressure from underneath when no power is on, then retract when power is applied. Any thoughts on the matter are welcome.

Does it rotate back to the exact same position at completion of scan? If so I think I have a solution for this.

No, it stops in an arbitrary position.

Really kool dude. I am kinda interested in your reconstructme software as well. Do you find it easy to use?

Since I'm a Mac guy, it was a pain to get Windows installed under boot camp and get AT
amp;T the right drivers to run ReMe, but after that's over it's pretty easy going.

I've considered making one of these before, but my problem with moving a person around is they might stumble. Wouldn't it be a better idea to keep them stationary and move the camera around them?

As long as the turntable moves slowly, I think this is a non issue. Moving the camera wold create issues with twisted wires and enlarge the footprint needed to work within.

Awesome project!!

This should drastically reduce the price:

It's a turntable that you can buy from McMaster Carr for about $4. It's got a 500 lb max capacity, so it should all but the heaviest of subjects!

You may also be able to do away with the pulley system by using a rubber wh
eel on the shaft of a motor like one of these:

Just orient the motor vertically, and put the wheel in direct contact with the edge of the turntable platform!

I've used the lazy-susan type bearings similar to the McMaster link you provided. I can attest that standing on it can result in some clunky movements if the weight is not evenly distributed. However, in my applications, the objects were large, but not heavy and the bearings worked great. Picked them up from Home Depot for about $10.

I looked at these bearings at McMaster-Carr but in my past experience with these bearings, if the weight is unevenly distributed they will not spin well. With the larger platform size IMHO, I don't think this will work well, but I'd love to be proven wrong.

If you watch the video http://cheesycam.com/motorized-lazy-susan-heavy-duty/http://cheesycam.com/motorized... , you'll see that the larger pulley underneath makes it a lot easier to spin, as opposed to a motor attached directly to the shaft. The rubber wheel approach could be good as well. I'm thinking a stepper motor with a pull
ey may be the easiest implementation, as opposed to having to mount the motor under the platform.

This looks great! Can't wait to try it out.

one cheap motor alternative.

get a motor from a rotisserie (i see these at garage sales a bit)

they have low rpm and High torque and usually are powered from AC outlet.

I have two thoughts about where to go with the motor:

1) Stepper motor with a pulley. Once the table is turned on, this should just start the table slowly turning so the scanner could start at the bottom and work their way up the subject.

2) I was thinking about a sewing machine motor and a foot pedal. I think that a foot pedal would be a good cont
rol for the person scanning to be able to rotate the table, but maybe a continuous turn would be easier so the scanner person doesn't have to do too much at once.

So far I think #1 is the way to go. I'm curious about trying one of those rotisserie motors- that could be good if there are speed cont
rols for those.

Rotisserie motor has low RPM (uses gears for strong torque)

I would bet like a sewing machine motor, you could use

a high curent resistor (rheostat) like a dimmer switch.

the reason i would lean towards the rotisserie is it is

a simple drive that wouldn't need much in the way to control it.

a quick look on ebay and amazon showed they can had for as low as
~= $20. i saw a heavy duty one for roughly $50.
so that and a dimmer and you have a variable speed high torque solution.
for under 40 at the low end.

Thanks. I will give this a try. I think a constant rotation, low rpm motor that won't trip up the subject is the way to go. My methodology once I start has beet to do a quick up and down movement to confirm the subject was fully inside the scan area, then I start at the bottom and move upwards, ending with the face and top of the head.

Going the opposite direction I often ended up having bad geometry around the ankles.