Crayon extender (Crayola, Plastidecor and similar)

I couldn't find a crayon or pencil extender for my kids' crayon scraps. The commercial ones were either too expensive or too difficult for kids to handle. So I designed one myself.

Advantages:

• Easy and fast crayon change.
• Optimized for 3D printing.
• Lightweight and narrow. Designed with minimal perimeter to add the smallest possible diameter to the crayon.
• No threads: simply slide to hold or release the crayon.
• The clamp attaches at the back so it doesn't get lost when the crayon is out.
• Holds crayons less than 1cm long (not counting the outside)

Disadvantages:

• Because it has very little material, it is prone to breakage. Especially when there is no crayon inside. Therefore it would not be suitable for very young children.
• The model is designed for 8mm diameter crayons. It will not work for other sizes.

This is one of my first designs so I would love it if you try it out and leave me your opinion and ideas to improve it in the comments.
 

Recomendations:
 

The models come already oriented in the recommended printing direction.

When moving the outer clamp, hold it by the hole side (not the side incontact with the inner side) and apply light pressure. This will reduce friction and allow the clamp to slide more easily:

Other models

If your children like to draw you might be interested in my Isometric drawing dot grid template.  It allows anyone to create an isometric grid of points quickly: