Step Motor or DC motor for rotation but hollowed inside?

Using Arduino Motors, Mechanics, Power and CNC
1

I am looking for a motor which rotates, but which is hollowed inside. Something like this Rotating Door Lock DC Motor : ID 3881 : $2.50 : Adafruit Industries, Unique & fun DIY electronics and kits, but where the rotating part is a hollowed ring. Essentially, something similar to this https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_ID=8750, but possibly 1 or 2 orders of magnitude cheaper :slight_smile:

Does anyone know any model for this purpose?

2

I have seen stepper motors with acme thread shafts going through the center. I don't know how large a hole you need.

3

Use a worm gear approach to the problem. Build the thing using a motor and a worm gear and a hollow pipe.

4

Did you try Googleing: "hollow shaft stepper motor", I got a ton of hits. How big do you need to opening in the shaft to be?

openstep
openstep332×533 147 KB

5

Yup. This isn't hard to DIY with parts from Amazon if you have some time. And you can make it as precise as you need for fairly low cost.

@OP: what's it for?

6

Thanks! Ideally I would need hole with 1 inch diameter, but for initial stuff I could work with 0.5inches

7

Thank you! I actually did not know the proper name for this devices :slight_smile:

8

Thanks! Can you reccomend any resources that I can consult to learn more about it? It would be great if I could buy all parts from Amazon, indeed!

I work in an optical lab, we use those expensive (>$1.5k) motors to rotate lenses and other optical elements, so I am looking for cheaper alternatives. Even something in the hundreds of dollars range would be a huge improvement for us :slight_smile:

9

Could you adapt a large pully that is belt driven? I'm thinking of RC parts. You would have to attach the pully to a different bearing and drill out the center, but I would be surprised if that would be difficult.

10

Servocity and others host Actobotics and goBilda gears of many types and sizes, intended for DIY projects:

Ones like these have up to 32 mm bores, but the inner diameter could easily be increased on a lathe. Or mount your DIY thingy-holder onto the gear face and use the gear as intended.

11

That depends on the tooling you have at your disposal and your experience. If you're asking the question here, my guess is you don't have the tools you need to build something like this accurately.

Let's start by asking how precise you need the motion to be?

12

Are you an owner or investor? Even buying a used machine would be quicker than you experimenting trying to make one. The actual cost of the machine is offset by how quickly it can pay for itself, not the list price.

13

you might expand your search to include hollow shaft servos. Not sure if that will integrate with your setup, but something to look at. Also might have a look at frameless motors, basically just the rotar & stator, no shaft or housing, you're meant to add your own.

good question & we really need to know both your angular tolerance and your runout (facial) tolerance. I dont know a lot about optics, but I know they run on tight tolerances. I suspect thats why those lab motors you linked to are sooo expensive, cost goes up exponentially with precision, no way around it.

I do like the belt drive alternative someone suggested. Just how willing & able are you to fabricate this sort of thing? You got a lathe?

edit: looks like some places actually call them "pipe drives" so my trying searching that too.

14

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.