Marblevator Baby Steps Revisited





Introduction: Marblevator Baby Steps Revisited

About: Formerly the owner of a company that designed software for avionics (EFIS, FMS, etc.) and video games (Tetris, Robocop, Predator, Michael Jordan in Flight, and a number of others), I'm now retired and finall...

Marblevator Baby Steps Revisited is an improved design of my previous Marblevator Baby steps.

One of the improvements is that the stair steps ("Step 1.stl" through "Step 5.stl") no longer fall out when Marblevator Baby Steps Revisited is turned upside down (this improvement is thanks to grandkids and "how does it work" enthusiasts). Another is a small compartment designed to contain the "marbles" when not in use. Finally, the surfaces are smoother and more continuous than the previous design thanks to some of the design tools available in Autodesk Fusion 360.

The design features two operating knobs, one in the front and one in the rear. Either knob can be rotated in either direction to operate Marblevator Baby Steps Revisited, so it is easy for left and right handers to operate.

You will need to purchase at least one 8mm (5/16") diameter ball bearing to use as the marble.

I probably forgot a file or two or something, so if you have any questions, please feel free to ask.

Designed using Autodesk Fusion 360, sliced using Cura 2.3.1, and printed on both an Ultimaker 2+ Extended and an Ultimaker 3 Extended.

Step 1: Print and Prepare the Parts.

I printed my parts on an Ultimaker 2+ Extended and an Ultimaker 3 Extended using .1mm vertical resolution and 20% infill.

Print two "Knob.stl" and five "Cam Lobe.stl", and one each of the remaining parts.

Printing "Base.stl" with supports is optional. I printed one base with supports, and a second base without. With some cleanup, both worked fine.

Prior to assembly, test fit and trim, file, sand, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on the colors you chose and your printer settings, more or less trimming, filing and/or sanding may be required.

Carefully file all edges that contacted the build plate to make absolutely sure that all build plate "ooze" is removed and that all edges are smooth. I used a flat jewelers file and plenty of patience to perform this step.

Step 2: Install the Steps.

Slide each of the five steps into the respective guide slot in the bottom of "Base.stl", making certain that each step faces the correct direction and is in the correct position. "Step 1.stl" is installed in the slot nearest the short end of "Base.stl", and "Step 5.stl" is installed in the slot nearest the tall end of "Base.stl".

Step 3: Assemble the Axle and Cam Lobes.

After the steps are installed, the axle and cam lobes are assembled in place. The assembly procedure occurs inside the bottom of "Base.stl" and is somewhat like threading beads on a needle.

Start by inserting "Cam Axle.stl" into the axle hole nearest the short end of "Base.stl".

Next, one by one, slide one "Cam Lobe.stl" onto "Axle.stl", alternating the orientation of each by 180 degrees. The position of each cam lobe on the axle will be set later.

Step 4: Install the Knobs.

Press one "Knob.stl" onto each end of "Axle.stl".

Step 5: Align the Cam Lobes.

I used needle nose pliers to align the cam lobes with the steps.

Holding the front and rear knobs with one hand, slide each cam lobe into position directly above its respective step using needle nose pliers. It is important that each cam lobe only contacts its own step and not an adjacent step.

Step 6: Install the Door.

Slide "Door.stl" into position in the door opening in "Base.stl" and you are done!

Hope you like it!



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    19 Discussions


    1 year ago

    This is super mesmerising. I like the creativity in your designs. Where do you get your ideas/ inspiration from?

    1 reply

    Thank you very much!

    For marble machines, I used to build them out of brass wire, then when I bought my first 3D printer, I build this: Since then, I try to make them either smaller, or just different such as this one.

    I also enjoy automata, and I've received many thoughts and ideas from a history of very talented people who have created some wonderful machines.

    And sometimes, I just want to make an air engine for example. Just jumped into my thoughts one day.

    Thanks again!

    I'm not sure if you have any available budget for a printer, but I recently cancelled an order on a $1000 PRUSA (very highly regarded hence 8-9 week lead time!), because I was concerned I might not use the thing after a couple of weeks.

    I did a bit of research and heard mostly positive things about the $200 Monoprice Mini Select, and I am BLOWN AWAY. It's built like a tank, very reliable, and the quality is as good as anything in the $1000 range. The only real limitation is the fairly small build volume (120mm cube). Free shipping on Amazon if you have Prime.

    I've replaced broken stuff around the house (slowly learning Fusion 360), and printed a ton of fun stuff from

    Love this 'ible, think it might be my next print, thanks gzumwalt!!

    Mixed emotions right now; I'm glad you like it but sad you don't have a printer!

    Is there a Fab Lab or equivalent near you? If so, perhaps they could help.

    Thank you, thank you, thank you!

    Your are welcome!


    1 year ago

    Amazing. My grand daughter will love it. And now I have an excuse to get a 3D printer. Instructables, the gift that keeps on giving.

    Thank you very much for posting.

    1 reply

    Thanks, I'm very glad you liked it, and hope your grand daughter likes it also!

    Thank you, I'm glad you enjoyed it!

    I like both 3D printers and the wonderful design tools available. I used to use Sketchup but found its limitations cumbersome. When I found Autodesk Fusion 360, the available tools make it much easier to design much more complicated 3D objects. This revisit took me only a few hours using Fusion 360, but the original took over 3 days using Sketchup.

    Technology, I love it!

    This is a really good idea! If I had a 3D printer, this would be one of the first things I would make!

    2 replies

    Thank you very much I'm very happy you like it!

    Have you tried to locate a "Fab Lab" or equivalent in your area? They provide 3D printing and other manufacturing technologies for little or no cost.

    Thanks again for your interest in this model, it keeps my inspired to continue designing, printing, testing and publishing!

    There is one close, but I don't think I want to go there for this.

    Thank you very much, I am very glad you like it!