Ages 14+

Mechanical Lock Box


Learn how a pin tumbler lock works and create a safe for your stuff! Follow along in the Maker’s Guide for step-by-step instructions to build the lock, assemble the door, and attach the box. Explore the science, engineering, and history behind mechanical lock box design along the way. Be inspired by other secret safe inventions to go beyond the build and make your own secret safe using items around your home.

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Additional details

From the desk of the product designer:

Behind the design

We started with a pretty small lock design, close to the size of a door lock. But at that small scale, the lock just didn't feel that satisfying to build, and the tiny pins were difficult to handle. So we sized everything up to make a jumbo-scale lock. This had the added benefit of making it easier to see how the locking mechanism works.

- KiwiCo Product Designer

By the numbers


Locking pin prototypes


Keys broken during testing


Total teeth on the large gear



2 reviews



    Great build . We really enjoyed it .

    Arya Deepak


    This is very well engineered and I use it a lot in my daily lifestyle.

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