Author Topic: Motorized lazy susan?  (Read 167 times)

Offline paulb104

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Motorized lazy susan?
« on: April 19, 2017, 06:04:23 am »
Hey :)

I'd like to build a small lazy susan out of K'nex. I've got a pair of the blue motors that I'd like to use with them. All my searching is coming up with nothing and I am NOT the creative type. I've tried. I know it's possible, I just cannot figure out how to do it.

I want to be able to put small objects on it for display.

Could someone point me to some plans?

Thanks so much!

Offline GWorks

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Re: Motorized lazy susan?
« Reply #1 on: April 19, 2017, 11:05:43 am »

Hey @paulb104 ,

I had to quickly google what a Lazy Susan is, but then it was clear to me. (To save time for people that just like me don't know what a Lazy Susan is: I've added a picture)

So, blue motor: Nice. Relative low RPM (rotations per minute). Black would be the best, as it is even slower. You will have to slow it down a bit I think. At least 1 time Blue to Red gear or one time Blue to Yellow gear (use the crown teeth). I didn't show this in my paint drawing.
Actually I have 3 or 4 idea's how to make it, but I don't know which would be the most successful.
I don't want to steal idea's, but can I give it a try?

As you didn't state the diameter of the plateau you want to rotate, I'm going to assume it's something like 25 cm (±10" ) I'm going to use @GargamelKnex 's Fruit tray as base: https://www.instructables.com/id/Knex-Fruit-Tray/

If I make it, and it succeeds, plans (instructions) will be available of course :)
« Last Edit: April 19, 2017, 01:37:30 pm by GWorks »
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Offline paulb104

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Re: Motorized lazy susan?
« Reply #2 on: April 19, 2017, 01:14:24 pm »
Exactly!

I'd want a plate like that, spinning slowly, then I'd put something on top of that.

I had NO idea the motors were color coded by speed. We picked up ours at goodwill, still sealed, for almost nothing. Last Wednesday we just got another one but it's clear. I haven't even put batteries in it to try it yet...

My searches for 'turntable' were all about record players...

Ultimately, what I'm trying to make for myself it something like this: https://youtu.be/Mi3bsdfLdm8?t=1m58s

Again, I know it can be done, but I'm just tired of fighting with the stuff. I've built other things with my seven year old daughter's K'nex, small projects, while she's at school. She gets such a kick out of it. Once I had a hundred year old photo that was a about forty inches long and ten inches high and as thick as cardboard but it was rolled up. It had to sit in an enclosed box filled with hot water but not actually touch the water to unroll. I built a platform the size of the tub, half as high, filled it with water, put the k'nex in, then the photo, and sealed it. Worked like a charm. That alone was worth the price of the K'nex!


Offline GWorks

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Re: Motorized lazy susan?
« Reply #3 on: April 19, 2017, 01:36:55 pm »
Aha, nice.

Do you happen to have a microwave oven? Go and check how the platform rotates. That's one way to do it (it's a ring with 3 or 4 wheels with a spinning plate on top of the wheels)

Does it matter to you if the platform is lifted 10 cm (4") off the ground? Of course, the lower the better. Just now I'm seeing that the motor is pretty thick, so it elevates the platform quite a lot.
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Offline paulb104

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Re: Motorized lazy susan?
« Reply #4 on: April 19, 2017, 01:41:45 pm »
I don't think it matters how high, as long as it's stable. I did take into consideration my microwave turntable, which has hub in the middle and the ring of wheels about two thirds as wide as the plate. Didn't help me any :D

Offline GWorks

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Re: Motorized lazy susan?
« Reply #5 on: April 19, 2017, 07:42:49 pm »
Still working on it. the gearing is harder as it seems.


Could you tell me which motors you have available?
Blue battery motor (34 rpm), transparant battery motor (34 rpm)... anything else? like the gray 12V motor, powered from the grid?
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Offline paulb104

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Re: Motorized lazy susan?
« Reply #6 on: April 19, 2017, 08:44:33 pm »
These are what I have...

Two of the blues, and the clear, well, those batteries exploded a number of years ago. I don't know if I've got the skill to get that working again.

Offline paulb104

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Re: Motorized lazy susan?
« Reply #7 on: April 19, 2017, 08:48:06 pm »
...and thanks for working on this with me :)

Offline mathsboy314

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Re: Motorized lazy susan?
« Reply #8 on: April 20, 2017, 05:44:44 am »
If you're happy with the turntable going at 5.8 RPM then the gearing wouldn't be too hard, as you'd only need a small blue and large yellow gear.

Offline GWorks

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Re: Motorized lazy susan?
« Reply #9 on: April 20, 2017, 09:43:14 am »
@mathsboy314 @paulb104

I've got a working solution :) It's turning at a nice rotation speed. I've used the grey 12V motor and 2 Yellow gears (gear reduction 6:1 & 6:1 final rpm = 2.7272 rpm, that's 22 seconds each rotation)
I will adjust the design so, that you can also use a battery motor.
Perhaps to fix your transparant motor, use this guide: https://www.instructables.com/id/Knex-motor-modification/
I hope to make instructions later today ;D Here are two pictures already.
« Last Edit: April 20, 2017, 09:52:59 am by GWorks »
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Offline mathsboy314

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Re: Motorized lazy susan?
« Reply #10 on: April 20, 2017, 09:56:20 am »
I really like how compact that is.

Offline paulb104

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Re: Motorized lazy susan?
« Reply #11 on: April 20, 2017, 01:07:59 pm »
That's second picture is awesome!

As I'm staring at it, I got a scary thought - I might not have all the pieces!

Offline paulb104

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Re: Motorized lazy susan?
« Reply #12 on: April 20, 2017, 02:31:10 pm »
Does that whole thing spin, not just the top? That seems like it would be awfully heavy. I was trying to do something like this
https://s-media-cache-ak0.pinimg.com/564x/90/61/5b/90615b2d6827b0a96b3599d277056b0a.jpg

Can that blue pin in the center be made flush with the top?

Offline GWorks

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Re: Motorized lazy susan?
« Reply #13 on: April 20, 2017, 02:44:30 pm »
The circle and the border rotates. The bottom structure stays put. It's about 500 g - 1kg (1 - 2 lbs) It's not light. but the wheel structure that you've shown me must weigh more I think.
I made the blue rod a little more flush. But completely is not possible in this design.

Parts count plateau:
8x4x2 = 64 yellow connectors
116 white rods
96+120= green rods
69 white connectors
Structure:
±17 blue rods
±16 blue 3D connector
±24 purple(silver) 3D connector
±4 yellow connectors/white connector

2 big gears, 1 small gear, 1 gear without pinholes (dark grey)

It's a rough estimate of parts... which part do you think you don't have sufficient?

« Last Edit: April 20, 2017, 02:52:46 pm by GWorks »
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Offline paulb104

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Re: Motorized lazy susan?
« Reply #14 on: April 20, 2017, 03:04:38 pm »
The circle and the border rotates. The bottom structure stays put. It's about 500 g - 1kg (1 - 2 lbs) It's not light. but the wheel structure that you've shown me must weigh more I think.
Before I say anything else, please keep in mind I'm an utter novice with this stuff :D

In the picture that I was using the wheels would be all on a surface, and the turntable top would be supported by the wheels.

Does your border have any support beneath it? Maybe I'm just not seeing it.


I made the blue rod a little more flush. But completely is not possible in this design.

Parts count plateau:
8x4x2 = 64 yellow connectors
116 white rods
96+120= green rods
69 white connectors
Structure:
±17 blue rods
±16 blue 3D connector
±24 purple(silver) 3D connector
±4 yellow connectors/white connector

2 big gears, 1 small gear, 1 gear without pinholes (dark grey)

It's a rough estimate of parts... which part do you think you don't have sufficient?

My biggest concert is those two big gears! I cannot recall if we have them.

Other than that, it's just the quantities of the items. We get our pieces in bulk, but only when we see them at thrift shops. We get them stupid cheap, too. Every three months our goodwill's have a half price day and we got a box that is a twenty four in cube completely filled with k'nex, for $7.50. That's where the clear motor was. For a seven year old who plays with them occasionally we have a lot of k'nex. To build a specific project like this.... I don't know. I'll have to bring it all out and do inventory.

And, again, I'm truly appreciative :)