Windup Bunny

by gzumwalt, published

Windup Bunny by gzumwalt Mar 5, 2016

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34906Views 6065Downloads Found in Animals


I am yet again truly honored and humbled, this time by the Thingiverse feature of Windup Bunny. Many thanks yet again Thingiverse for the feature! And many thanks to all of you who made, liked, commented, critiqued and/or added to your collections, Windup Bunny!

My 100th Thingiverse published design is Windup Bunny, which is yet another incarnation of the PLA Spring Motor Demonstrator (http://www.thingiverse.com/thing:402412) and the PLA Spring Motor, Rolling Chassis (http://www.thingiverse.com/thing:430050), in simplistic "open frame" design. All parts, including the spring, are 3D printed with the exception of the O-ring "tires".

Just in time for Easter, I made quite a few of these things for my wife (as she cannot eat chocolate, bunnies included) and of course for the kids and grandkids! Featuring all wheel drive to prevent "wheelies" and/or "back flips", the prototypes of this thing run about 15 feet (4.572 meters) after lubrication and break in on a smooth surface.

Video of prototype is here: https://www.youtube.com/watch?v=J8FdtqQLwls (no one was available to help with the video, so I shot it on the desktop, sorry).

If you do not prefer the "open frame" design (as in Saber http://www.thingiverse.com/thing:1212665, I like the open frame design as it demonstrates the gear movements, etc., and in this application it is lighter in weight which improves travel distance), I've included optional solid body side panels "Body Left, Solid.stl", and "Body Right, Solid.stl". Hopefully Loubie will create 3 dimensional side panels!

Print yours in the colors of your choice, and Happy Easter!

Designed using Sketchup Make 2015. Printed in PLA on an Ultimaker 2 Extended using Cura settings as described in Print Settings.

Print Settings

Printer Brand:



Ultimaker 2








20%, with exceptions, see notes.


.4mm nozzle.

All parts were printed at 20% infill with the exception of "Axle Spring.stl" and "Spring.stl", which were printed using 100% infill, which is necessary to assist in the prevention of torsion failure ("Axle Spring.stl") and delamination failure ("Spring.stl").



Thingiverse member 510thousandths posted a 3D printable o-ring using flexible filament here: http://www.thingiverse.com/thing:1443688/#files. I have not yet tried it (as I do not have flexible filament), but I plan on doing so. Thanks 510thousandths for your input!


Parts I Purchased:

1) #18 O-Rings (1 3/16" OD, 15/16" ID, 1/8" D) (Amazon, Lowe's, Home Depot, etc., Danco 96735). The box I purchased contained 10 O-rings.


Print all pieces as shown in "Assembly.skp" or "Assembly.stl".

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, your printer and your printer settings, more or less trimming, filing and/or sanding may be required. If the tight fitting components are too loose, add a small dot of thick cyanoacrylate to the side(s) of the male component, allow to dry completely (I use accelerator to speed the process), then try the fit again. Repeat until tight.

Assemble as per "Assembly.skp" (or "Assembly.stl").

Apply light machine oil to all moving contacting surfaces.

Questions, problems, complaints, etc., please feel free to comment and I will do my best to resolve them.

Hope you enjoy it, and Happy Easter!

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I printed everything out, but it took a lot lot lot of filing to get the spring, winder and gears to fit together. Then when it did go together, the gears would barely move after winding all the way. Then the axles did not fit into the wheels - I mean they were way off. I was tired of filing, so I smashed it with a hammer. It is a neat design, but there is only so much filing and sanding I can do.

I'm very sorry.

Hey, I am the one who is sorry. I have been 3d printing long enough to know it takes more than one shot. I will try printing the winder and the axles a bit smaller in 2 dimensions and that should make it easier. It is a great design!!

Thanks for you kind words, but I'm never happy when someone has problems with designs I've attempted.

If I can be of any assistance, please don't hesitate to comment or message.

Again, I'm very sorry for the difficulties you've had with my design.


After numerous prints with varying degrees of scaling, I finally managed to assemble you windup bunny model. However the only problem I am having now is that when I turn the axle spring to increase the spring's tension, the gears refuse to move. I was wondering if you had any advice to remedy this. Thanks!

Do the gears rotate on their respective axels before assembly? If not, you need to slightly enlarge the center holes.

Before assembly, make sure "Gear Spring.stl" and "Gear Idler.stl" rotate freely on their respective shafts.

Hope this helps, if not, let me know and I'll do what I can to help solve it.

Also, the gear drive wont fit on the axle

I am again truly sorry for the difficulties you are having.

Are you printing with PLA?

Also, "oozing" can be a problem requiring the use of a modeling knife or drill bit to resolve.

Don't give up, and keep me posted.

The foot axles are not fitting into the rings, this is concerning.

Mar 29, 2016 - Modified Mar 29, 2016
gzumwalt - in reply to iceknight27377

I am sorry you are experiencing difficulties but I am unsure as to exactly what problems you are having.

If "Axle Foot.stl" is not fitting into either "Wheel Front.stl" or "Wheel Rear.stl", it is probably do to "oozing" (the hole into which "Axle Foot.stl" is installed is on the build plate side of the print, and if the build plate is too close to the print head, it will cause the filament to "ooze" or "spread out" during printing and as such will make the hole slightly smaller at the outer edge). If this is the case, it can be solved by using a modeling knife to slightly increase the size of the holes in the wheel components.

If I have not addressed the issue you describe, please do not hesitate to comment again and I will do my best to resolve the issue.

Again, my sincerest apologies for the difficulties.

This is a fully 3D printable design, right?

Mar 27, 2016 - Modified Mar 27, 2016
gzumwalt - in reply to Rainess

With the exception of the #18 o-rings used as "tires" for traction (one could substitute rubber bands, but the wheels are designed for #18 o-rings), yes the remaining components, including the spring, are 100% 3D printed. I've printed 11 of them and am printing the 12th now for a trade show. Check out the instructions for more details on the printing and assembly process.

If you wish to go 100% 3D printed, checkout 510thousandths 3D printed tires here: http://www.thingiverse.com/thing:1443688/#files. He uses flexible filament which I plan to try myself soon.

Hope you print one!

#18 O-ring
Mar 27, 2016 - Modified Mar 27, 2016
Rainess - in reply to gzumwalt

Thanks! I am printing one, and I do have flexible filament so I will print the O - ring. Could you really quickly enlighten me on how many of each part I need to print?

From Thingiverse member Lindsrom923,

Lindstrom923 - in reply to PetterP
One of each part EXCEPT FOR:
Axle X 2
Axle Foot X 4
Gear_Drive X 2
Wheel_Front X 2
Wheel_Rear X 2

If you have any further questions or comments, please do not hesitate to comment or message me. My goal is to get you to successfully print Windup Bunny!

Thanks so much! Will share a picture when finally printed :)

Check out my model. Its a great Easter gift for those handymen in your life.


Vise (Fully 3d printed)
by jdog13

Good Modeling! it's very cute


Mar 26, 2016 - Modified Mar 26, 2016

Hello there, I'm new to 3D printing. I have a Zortrax M200 and my first 4 prints (ball bearing, nautilus shell gears, inception top and coin-op bottle opener) have all turned out really well. You could probably say I have drunk the Kool-Aid and I'm hooked. That being said, I don't want to try and fly before I can walk (still kinda learning to crawl at this point). So, would you say your model is more for the intermediate to advanced hobbyist? Also, when I eventually do get around to printing it, roughly how long would you say it takes to 1) print, 2) prep for assembly, 3) assemble? Thanks

It's a pretty easy print, and depending on your printer size, settings, and speed, can be printed in a few hours.

As far as assembly, depending on your printer settings and the colors you use, it may take only 15 minutes or so to assemble, but could take an hour or so for sanding, filing etc.

I designed Windup Bunny with the fewest parts I could, so compared for example to Saber (http://www.thingiverse.com/thing:1212665), I would say a beginner with previous printing and assembly skills could print and assemble one with relative ease.

Hope this helps!


Thanks for the reply. I'll probably give it a try next weekend.

This comment has been deleted.

I made a file for a #18 O-ring if you have flexible filament to use.
Fits just fine on my Windup Bunny!
Fun design gzumwalt!

#18 O-ring

I've added a reference to your tire design in the instructions, hope you don't mind.

Many thanks again!

Glad to help! Now it can be 100% 3d printed! Love this design!

Many thanks!

I'm going to order some flexible filament and try it out for this and future designs.

Great suggestion!

I want to print one but only have one color pla but a lot of abs. do you think I can print all the parts except the two spring motor parts in abs and have them fit together ok

I haven't tried to use differing materials as all I have is PLA.

Since the tolerances are not that tight, I would think that printing in ABS would be fine, but cannot confirm.

Please let me know if you try ABS and how it worked out.

Just started printing in all ABS. Will let you know how the spring works... my kids are super excited!

maybe I'm just missing it but the knob does not seem to be in the stl files

Mar 25, 2016 - Modified Mar 27, 2016
gzumwalt - in reply to frogman55

Yes, that's my fault.

The knob is part of "Axle Spring.stl". I just combined the axle and knob to avoid further interconnections.

My fault, and truly sorry for the confusion.

I did the slicing of all the pieces, but the spring has several mistakes that I can not fix with Netfabb.
Someone managed to solve?

Thank you and congratulations for the project.

Gian Francesco

I checked the spring again and did not find any errors. I'm using Sketchup Make 2016 with the Solid Inspector plugin.

Can you provide more detail?

I have solved.
It was a problem in exporting as obj. Now exporting to stl everything is ok.
Thanks so much

Mar 24, 2016 - Modified Mar 24, 2016
gzumwalt - in reply to gtiramani

Great, glad your're now printing!

Let me know if you have any further issues and I'll do what I can to assist.

Missing the outer wall.

I can attach a picture?

I will look into it.

And thanks!

Awesome design. Might have to make a couple "construction kits" for my niece and nephew for Easter gifts. Had some problems with axles being too short and the wheel rubbing the frame. I extended the axle by 6mm in 123D design (see remixes.) Will update when I get a chance to try the longer axles. Thanks!

Mar 24, 2016 - Modified Mar 24, 2016

Make a moving schooner next??? This is cool! Ever used Lulzbot? What design programs do You recommend?

Moving schooner...


I use Sketchup Make 2016 as it's easy to learn and it's free for everyone to download.

hi gzumwalt that's an awesome windup bunny nice work i'm goin to try to make 1 thanks 4 posting

This comment has been deleted.

Many thanks, I hope you do make one!

Will it work in ABS? My da vinci doesn't like PLA.


My Ultimaker 2 Extended prints in PLA, ABS and other materials, but I only have PLA.

The tolerances aren't too tight, so it may work with some additional tweeking.

This looks great, I think I'm going to try printing it at half size so the kids don't jam their fingers on any gears. That should still work, right? I think I can just use rubber-bands instead of the sealing gaskets

Mar 23, 2016 - Modified Mar 23, 2016
gzumwalt - in reply to Res0lu7ion


If you reduce the size by scaling, you will reduce the gaps between the components also, thus additional trimming and sanding may be required.

Hope you make it!

Will this work without the rubber things

Mar 23, 2016 - Modified Mar 23, 2016
gzumwalt - in reply to DPS2004

I don't know that it would have enough traction given the initial spring force.

Small, wide rubber bands may work.

Mar 23, 2016 - Modified Mar 23, 2016
DPS2004 - in reply to gzumwalt

i have too many rubber bands to count! i might get it to work.

It's a pretty easy print, hope you try it!

WOW! beautiful design. keep up the great work, I will have to try and make something that uses this spring!! Question: Have you seen any fatigue in the PLA spring? in other words does it loose springiness after many uses?

Many thanks for your kind words!

As of yet, I've never had a spring fail by either breaking, delaminating or weakening. I do print the spring with 100% infill.

But then again, tomorrow's another day...

I loved the pla spring rolling chassis. What a cute idea this is.

Mar 23, 2016 - Modified Mar 23, 2016
gzumwalt - in reply to jdog13

Thank you, I'm glad you like it!

Congrats on getting featured!

Thank you very much!

Mar 19, 2016 - Modified Mar 19, 2016

Could someone please list how many of each part is needed? Assembly.stl is a bit heavy for my old 2007 computer :-|

One of each part EXCEPT FOR:
Axle X 2
Axle Foot X 4
Gear_Drive X 2
Wheel_Front X 2
Wheel_Rear X 2

Thank you very much. I have printed almost all now, need the spring, one gear drive and an axle foot. very excited about if I can get it to work. Only have rubber bands for the wheels but I don't expect that to be a big problem.

Congratulations on your 100th upload.

I'm stuck on 99 at the moment!


It took me quite awhile and included buttons and knobs, but I made it!

Dude! you got featured!

Double Congratulations.

Thanks yet again!

ha this is cool! it kinda riminds me of an energizer bunny ;)P


No connection to the battery bunny was intended! :)

awesome work

i wish i had your talent and creative mind!

Mar 5, 2016 - Modified Mar 23, 2016
gzumwalt - in reply to TheLastSaxon

Many thanks for your kind words!

Please read this article, especially the last paragraph, on how I believe I obtained "my talent and creative mind": https://blog.adafruit.com/2014/10/02/community-spotlight-greg-zumwalts-automata-mechanical-toys/.

Do we print the spring from the spring demonstrator? Is that the only part we need from the other model? Keep up the cool work!


Mar 5, 2016 - Modified Mar 5, 2016
gzumwalt - in reply to mr_tim34

All parts should be included in the download. This spring, gears, etc. are not the same as those in the PLA Spring Motor Demonstrator. If I've forgotten a part, please let me know!

OOPS! I just noticed thanks to your comment I neglected to include the spring ("Spring.stl") but instead uploaded two pawls ("Pawl.stl", "P"awl, "S"pring, oh my old eyes)! Only one pawl is needed and the spring should now be uploaded.

My sincerest apologies and many thanks for pointing that out!