Marblevator Baby Steps Revisited

A revisit of an earlier design


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

A video of the prototype is here: .

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.

Materials and methods

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.

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".

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.

Install the knobs.

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

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.

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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930c255dcc578b011be4cd06726548ca?default=blank&size=40RoboTICs added this to the Toys collection ago
C6bb61fe38c9e9027d707b0d0dccae45?default=blank&size=40BGham added this to the To Make collection ago
80942b00fb47059dfca8b4934fb2fdf4?default=blank&size=40Christopher Settle added this to the test prints collection ago
5476e02dad6c204c771502862bd52b87?default=blank&size=40Cody Barnes added this to the Desk Toys collection ago
717e271ca4423b91567a16c1053c49d6?default=blank&size=40aviphysics printed this ago
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Printed on:
Ultimaker - Ultimaker Original
All the parts fit beutifully together, except for the cams, which were too tight to slight onto the shaft. I printed a second set of cams that were 5% larger, and they worked nicely, though an extra 3% might have been enough. This problem with the cams was a little surprised, as the knobs seem to have the same size hexagons in the model. I had already shaved off the tiny bit of over extrusion from the first layer, so I am not sure what the issue was.
923493e3bdd1530d4ae9909f093657a3?default=blank&size=40leadboss added this to the Things to print collection ago
Mini 645ospalh added this to the Maybe one day collection ago
E4f706714d206834050b3e5682d7256e?default=blank&size=40ac8gt added this to the Toys collection ago
46416423ab17abb9a0b349c421006da5?default=blank&size=40Timewarpped added this to the Toys collection ago
Eccfe77b107ddcfd30f257050c7299ab?default=blank&size=40Devon Kearns added this to the Toys collection ago
Mini lora and iGreg Zumwalt published this design ago