Tumbling and Twirling Gymnast Toy! (TinkerCAD & 3D Printing)

It's summer and this year it's a special one because the Olympics are finally happening!!

I wanted to put together a bit of a project to commemorate that that's fun but also could be educational if you wanted it to be!

The gymnastics are easily my favourite part of the Olympics - it's just astounding to me what human beings can do so I started thinking about what I could possibly make that related back to that and the vaguest memory of a toy started coming to me - I couldn't picture it or even remember what it did but I knew it existed!

A little googling later and it was all flooding back.. It was an old fashioned wooden toy with a circus animal that spins and tumbles when you squeeze the frame of the toy!

The movements reminded me of the Olympic gymnasts on the bar so I tried my best to model my printable recreation of the toy after them!

I won't be going into lots of detail on the design of this toy as I think there are enough steps here with the assembly etc. to make a decent activity/project and there was a lot of just working by eye in Tinkercad, rather than any kind of repeatable technique anyway.
I'll share the project here though in case you'd like to change anything or explore the design process a little yourself!

It could be a fun extra learning step if you're doing this with your kids/student to see if they can model their own gymnast figure! It would work just fine with simpler shapes too - they'd just need something roughly leg shaped, something roughly arm shaped and a torso-ish shape with a head to attach them to!

• Tinkercad - if you want to make any changes to the model
• 3D printer
• Filament
• String
• (Optional) Beads/Other material to use as spacer

I'm going to link the Tinkercad project here again in case anyone wants to make any last minute tweaks to the design or wants it as a bit of a guide for making their own design from scratch before printing. Once you're happy though, either download the stls I've included below or export the models from Tinkercad.

Once you have your stls, it's time to get printing!

If you made your own or made any changes, be aware of any overhangs etc. that you may have created when slicing!

As per usual I'm not about to share a profile or gcode with you, I prefer to just give general guidance for slicing my models as different printers and materials vary so much that I'd hate to give you settings only to find they give you horrible results with your setup or even cause damage to your printer!

• My design was intentionally simple for ease of printing and requires no supports/rafts/brims etc to print.
• There are no tiny details in this, even the holes are a reasonable size so you can speed things up a little and print with a higher layer height (I used .3mm)
• I printed in PLA so know this works well - ymmv with other materials
• You need to print 2 Arms, 2 Legs, 1 Frame and 1 Torso

You probably noticed from the picture that I printed the frame in 3 pieces - on reflection can't see any reason to do that (in fact, if anything, it just introduces weak points) so I adjusted the design to print the frame in one piece instead.

There are a few different ways you could assemble your gymnast - I'll be using and describing a technique to make filament 'rivets' as I really like to try and use as little additional hardware as possible and it's a great way of using up those little scraps of filament we all end up with at the end of a roll!

If you're doing this with younger children, you may prefer to do this part yourself or just have them use string or wire in place of the filament pieces.

To use filament rivets:

(There's a clip above showing the whole process too which you may helpful!)

1. Cut a piece of filament a little longer than you need - I took about 30mm
2. Using a lighter or any hot tool, heat the very end of your piece of filament until it starts to melt
3. Using a flat surface (I use a metal scraper but you can just use a table top etc.) flatten the melted end of the filament
4. Pass the not flat end of your filament through the hole in the shoulder of one of the arm pieces, pass it through the hole in the top of the torso and then through the hole in the shoulder of the other arm
5. Trim away any excess filament so you have only a few mms poking out of the end
6. Repeat the riveting process on this end of the filament piece

Repeat this entire process for the legs too!

This is the last step to get our little gymnast tumbling!

You'll need your assembled gymnast, the frame and some string or thread.

(Optional) You may also like to create a spacer to go between the hands to ensure the arms don't catch on the torso - I just used a few beads but anything you can pass thread through will do -you could just cut a length from a drinking straw for example.

I've used a bright pink piece of string without a spacer in some of the pics above just to make sure it's nice and visible but then used black thread and beads for my own final model - the pink is just for demonstration purposes :)

• Lay your gymnast out with its hands above its head
• Arrange the frame so that the holes in the top of it roughly line up with the holes in your gymnast's hands (as shown in the pics with pink string)
• Pass your string through the lower hole in the frame, through the hole nearest the end of the hand in the first arm, through the same hole in the other arm and finally out of the bottom hole in the other side of the frame - check the pictures to ensure you have this right as it won't spin otherwise!
• Then loop the same piece of string back through the higher hole in the frame and thread the string through the other holes in both hands (don't go through the spacer this time) and out of the other side of the frame
• You can now cut the end of your string and tie it
  • You'll want to pull it tight just so there isn't any slack but be careful not to overtighten it - the frame shouldn't be pulled inwards by the string

I hope you had fun making your little gymnast!

To make them flip, you only need to squeeze the bottom of the frame as you can see in the clip above!

There's a knack to it as with all of these old fashioned toys but that's half the fun and this one's pretty easy to get the hang of!

If you're looking to build on this project as an educational activity I'd suggest exploring how the toy works:

• See if your kids/students can figure out how squeezing the end of the frame might make the gymnast spin.
• Explore gymnastics in terms of science as well as sport and look into concepts like momentum with them.

If you'd like to build on the creative nature of this project:

• Why not paint your gymnast to wear your country's colours?
• Or maybe try creating a whole new figure in Tinkercad?
  • The 2D nature of the figure makes it a good place to start if you're looking to learn/teach someone else Tinkercad :)