Layer by Layer: Retrofitting broken keychain hoops #3DPrinting #3DThursday

Solving a problem, not matter how small, is a great way to learning how to model things with CAD. When you make something that solves a problem, like let’s say fixing that broken keychain hoop on your IR remote, you’re more determined to get your hands dirty and solve it.

Broken keychain hoop

The Problem

Who hasn’t had this problem? A broken keychain hoop that’s even more inconvenient when the plastic part is integrated into the whole thing. Although newer stuff tends to use metal keychain hoops, our dated IR remote can become new again, nay, more stylish with the help of 3D Printing.


The Solution

A simple clip that will grasp onto the IR remote.


It also has cat ears. You know, for cute reasons. 3D Printing is about customization so why not?


The edges of the clip are inset, gradually covering the edges of the IR remote. The indents at the bottom keep the IR remote from falling out. It’s easily removable when the two sides of the clip are pulled apart.

123D Design Steps to fix keychain hoop

3D Modeling

Creating oblong oval geometry in 123D Design can easily be made using the polyline tool. Extrude the sketch to make a solid. To create the inset edges, duplicate the shape and shell it out. Subtract the shelled out shape with another duplicate of original shape so that it’s inset. Aplly yet another shell to the duplicate and merge it with the original shape so that greats an inset edge. Apply a chamfer to the bottom edges to avoid overhanging issues while printing, this also adds smoothness to the shape.


3D Printing

Projects like this are great for a Printrbot Simple Metal. Using Simplyify 3D, we used the following settings below.

  • %20 Infill
  • 50/90 Speed rates
  • 2 Shells
  • 0.2 layer height


I hope this project inspires you to start thinking about learning 123D Design. These basic steps could easily create this geometry in any other 3D Modeling app. What things would you fix if you had a 3D printing? Let us know in the comments below!
Thanks for reading, and remember – learn, make, share, repeat!

Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!

Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!

The Adafruit Learning System has dozens of great tools to get you well on your way to creating incredible works of engineering, interactive art, and design with your 3D printer! We also offer the LulzBot TAZ – Open source 3D Printer and the Printrbot Simple Metal 3D Printer in our store. If you’ve made a cool project that combines 3D printing and electronics, be sure to let us know, and we’ll feature it here!

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