Skip to content

Impossible dovetail box

Creation's quality: 5.0/5 (1 vote)
Evaluation of members on the printability, utility, level of detail, etc.

3D model description

An impossible dovetail box with a secret locking mechanism.

A magnet and a 15mm rod are needed to complete this project. I used a 4mm wide by 3mm long round magnet and a 3mm*15mm rod, but a section of M3 screw will work too.

There's a F3D file so you can edit the size of the holes if you need to.

Press the magnet inside the "Top" piece, place the rod inside the "Bottom" piece.


The secret to opening this box is simple, there are two holes on each side of the box, the one on the bottom is deeper than the length of the rod, but the one on the top is half as deep. When the box is shaken or put upside down, the rod sticks to the magnet, locking both pieces together.

To open the box again, hit the box against a flat surface, the rod will fall back to the bottom hole, and the contents will be revealed.

How hard and how many times you have to hit it depends on the strength of the magnet. A neodymium magnet like mine will make it a challenge to open, adding a piece of felt on the magnet, beveling or rounding the extremes of the rod will make it easier. I found out applying a little pressure to the side will stop the rod from bouncing back and locking again.

Please post your makes and comments to improve the designs. If you need some minor modifications I can do that for you.

Consider donating if this has been useful to you. Thanks!

3D printing settings

Material: PLA
Layer Height: 0.2mm
Nozzle: 0.4mm
Printer: Ender 3 Pro

  • 3D file format: F3D and STL
  • Last update: 2020/09/17 at 01:17
  • Publication date: 2020/04/18 at 20:05





Designs 22
Downloads 1.6k
Followers 22

I'm a student and a maker. My passion is electronics.
Paid designs go free after a couple months, make sure to follow me if you see something you like!

Collection associated with this 3D model

Best sellers of the category Game

Add a comment

Would you like to support Cults?

You like Cults and you want to help us continue the adventure independently? Please note that we are a small team of 3 people, therefore it is very simple to support us to maintain the activity and create future developments. Here are 4 solutions accessible to all:

  • ADVERTISING: Disable your AdBlock banner blocker and click on our banner ads.

  • AFFILIATION: Make your purchases online by clicking on our affiliate links here Amazon or Aliexpress.

  • DONATE: If you want, you can make a donation via PayPal here.

  • WORD OF MOUTH: Invite your friends to come, discover the platform and the magnificent 3D files shared by the community!