After I was on the instructables page again I took a look at the contests. There I discovered the secret compartment challenge. Immediately I looked around in my room and thought about which everyday object could be used as a hiding place. After a few thoughts I noticed a folding rule on my desk. Since I do a lot of crafts at my desk, such objects are always lying around.

A folding rule offers the ideal possibility to hide objects. The space is very limited, but this helps to keep the hiding place undiscovered.

The steps to modify the folding rule are very simple and can be done with simple tools.

Step 1: Parts

The number of parts needed is quite small, so the project is easy to reproduce.

You need:

- Folding rule

- Wood dowel

- File

- drill

- fretsaw or angle grinder with wood saw blade

Step 2: Creating the Locking Mechanism

First the outer two are folded out, as these will be used for the later opening mechanism. Then I used the scale of the folding rule to mark the holes. I drilled the holes for the locking mechanism one centimetre away from the metal folding mechanism to ensure that the function was not impaired.

For drilling I used a bench drill to create a vertical hole (6mm). You can also use a cordless screwdriver, but be careful to drill the holes vertically.

Then I pressed in the wooden dowels. No wood glue is to be used yet.

Step 3: Making the Pocket

Two centimetres from the wooden dowels, two more holes are drilled. Depending on how wide the folding rule is, the diameter of the holes is chosen. There should be at least 2mm space on each side to ensure stability. Use a sharp wood drill and drill the holes slowly. The material of the folding rule tends to splinter.

Afterwards the middle part of the ruler can be sawn out. Remove the wooden dowels to cut out each level separately. I used an angle grinder with a wood saw blade for this. You can also use a fretsaw, with this you can cut the material more precisely.

Afterwards the burr of the edges is removed with a file. The wooden dowels can now be pressed in again. If necessary, use some wood glue so that they sit firmly.

Step 4: Finish!

The secret hiding place is completed. Now you can store all your valuables. The only person who can steal them is someone who is looking for a folding rule. In this case the person probably needs the valuables even more than you do.