This safebox is an improved version from my previous designs:
https://www.thingiverse.com/thing:5853561
https://www.thingiverse.com/thing:5820868

Here is a new variation of my safe with a mechanical system and a four-number password. This prototype has a locking mechanism that can only be opened with the correct combination of numbers. Here, I add the functionality to change the password combination at any time.

The list of parts to be printed follows below. The number (e.g., "_x2") at the end of the file's name shows the quantity of each component you are going to need.

• box_x1
• box_x1_A (optional if you wanto to print the box in two parts to glue afterwards)
• box_x1_B (optional if you wanto to print the box in two parts to glue afterwards)
• dial_protection_x1
• disk_x3
• door_x1
• driving_disk_x1
• hinge_x1
• int_lever_x1
• knob_x1
• latch_x1
• lever_x1
• locking_ring_x2
• marker_x2
• position_disk_x4
• plug_x1
• spacer_x3

Be aware that the box walls are only 1mm thick, as I didn't intend to spend a lot of filament on this project. The size of the safe is 100x80x80mm.

Use the image "Instructions 1" to assemble the safe. It is recommended to use lubrication between moving parts.
The image "Instructions 2" shows how to glue the little marks on the internal disks (only the two intermediate discs have markers that require glueing). I opted to print the internal disks and the opposite marks separated, so I wouldn't need to use supports on this part. It also shows how to glue the box (if you opted to print it in two parts) and the dial protection on the door.

You can also watch the attached video for more information about how to assemble the set.

Tolerances:
• Fixed parts: 0.1mm
• Moving parts: 0.2mm

Note that the position you choose to fit the internal disks inside the external disks will determine the numbers on your password combination. You can disassemble those disks and change the password at any time.

ALWAYS perform some tests BEFORE closing the door of your safe. Take note of the numbers that need to be aligned with the marking on your dial and what way the knob needs to be rotated (clockwise or counterclockwise) to align all four disks with the latch.
I repeat: assemble the whole system on the vault door and perform the unlocking tests with the vault OPEN.

After you assemble the mechanism on the door, take time to understand how this kind of safe works. When you turn the external knob clockwise, it rotates the disk fixed on the shaft at the opposite extremity, inside the box. This disk turns and pushes, through the markers, the second disk. The second disk pushes the third disk, and the third disk pushes the fourth disk. When the indentation on the fourth disk aligns with the latch, stop the movement and take note of the number aligned on the dial with the arrow. This is your first combination number. Now reverse the rotation (counterclockwise) and proceed until the third disk is also aligned. Again, take note of the second number in your combination. Do the same for the remaining disks. Once all the disks are in the correct position, you have cleared the way to move the latch.

Here is an example of the combination shown on the attached video:

1. Rotate the knob three times clockwise to be sure that all the disks are moving together;
2. Rotate the knob clockwise until the number 19 aligns with the arrow;
3. Rotate the knob counterclockwise and pass the number 66 two times. On the third time, stop exactly at 66;
4. Rotate the knob clockwise, passing by the number 90 one time. On the second time, stop exactly at 90;
5. Rotate the knob counterclockwise, stopping exactly at 25.

At the end, you have the option to glue the extremity of the hinge pin and the little bottom cap if you want.

In case of difficulties, please send me a message and I can help you with further details.