Quadruple Portal Desk Toy

goood stuuuuuf :) THX

Assembly wasn't as bad as I was expecting based on the description and comments! Instead of glue I opted to drill some holes and use M3 screws to hold the frame together. I had 16mm screws but 17-18 would probably be a better fit. I had some red lithium grease on hand and it worked great for lubrication, but a thinner one might move more smoothly. The outer screw (unsurprisingly) wanted to fall over during printing so I added some support at the opposite side of the perimeter and it worked great.

There are a couple things that I think could maybe be improved:
* The top and bottom of the frame are paper-thin. I don't know if the flexibility is important for things to move smoothly, but if not it would probably be better to make those a bit thicker for better support.
* The clearance between the arms of the top and bottom is very tight compared to the rest of the tolerances in the model. The most tedious part of assembly was just filing those joints down until they fit together.
* As another commenter mentioned, if it's possible to have deeper grooves on the gear & cap pieces without adding too much friction, that would probably make assembly easier too.

Overall I like it a lot! Even though I know how the illusion works I still get fooled by it.

Really challenging (as promised), but maybe not in an enjoyable way. At least for me. More in a "f-----k, Why did my kid have to ask for this one?" multiple-nights-of-reprints kind of way.

Really appreciate the author's warnings, descriptions, and especially for including the CAD files. I don't think I'll want to touch this type of project again for a while, but I definitely think the following might help:

Use a thinner lube than grease. SuperLube 92003 (my go-to for metal lead screws) was too thick.

An assembly video from the creator, even if just linking to a decent walkthrough from someone else, would be lovely.

If remixing the model, consider:

A version with each gear side pre-attached to the screws. If you have a multi-material unit, you could paint the colors to match what's happening now, while also skipping many tolerance and micro-alignment-with-wet-CA issues.

The alignment issues are so frustrating, especially when mixing filaments with different shrinkage, that it might even be worth it to attach the other cap sides permanently too, even with all the support that would add. As the creator says, those are best printed with a few spots of tree support along the height anyway.

Consider a version where the tracks for the grooves have tall locator cones/pins, or generally rework the axles for use with small plane thrust bearings.

Maybe label the three connection points on the base and top with a small embossed "S, M, L".

Anyway, I'm glad this exists and was shared, sorry it won't be me to improve it. I need emotional recovery time.

Bambu Charcoal Matte PLA, Green Matte PLA, Dual Silk <-- all great
ColorFabb PLA/PHA transparent violet <-- I do not recommend for this due to tolerance issues. (edited)

I made this model but some of the parts did not fit together very well and the wheels do not turn and I failed in this model

Cool idea, almost impossible to put together. The thinnest/unspiraly spiral keeps breaking, and I can't fix it

Edit: now one star, because as soon as I put them together. the inner spirals snapped. I slowly started taking the top off, but that snapped as well. cool idea, waste of filament... (edited)

Nice model, but it is a nightmare to print and a nightmare to assemble.

I love this model. I do have a problem with the 3 internal "screws" falling out of the rings that hold them to the top and bottom.

Suggestion - Ada Cohen, It would be great if you could make the "RINGS" in the top and bottom pieced, taller so they hold the gears and top screw pieces in better. If they are taller (and deeper in the grooved pieces) they would hold the screws in better. I hope that makes sense. This would be especially useful when you shrink the whole model down. The screws seem to fall out of their ring holders easy.

Please let us know if this is ever updated. Thanks again.

this is a really cool trick my kids love it

I can't get a good print of the outer screw at the top so I want to try and scaled everything down to 75%.
Other than changing 100% to 75% scaling in CURA what are the other settings names I need to change and to what numbers to adjust the clearances?
Thank.

Very cool print. Fun to watch it work

One modification that would make the illusion even better is a cover on the base to hide the spinning gears. The large ribbon would need a small open slat along the path of movement. I have no 3d modeling skills, but I may try to make it by cutting a thin plastic sheet.