Barrel Cooper's Puzzle Box

This puzzle box design is deceptively difficult. Locate the the solution plaque and restore it to the front of the barrel to display mastery over this fiendish challenge.

As with all box-style puzzles, this design has a hidden compartment, but finding that is only the start!

https://youtu.be/Cz7uQzU-ICY

NOTE: This design has been updated to use a 4mm diameter dowel pin. Do NOT use a 6mm dowel as stated in the video below.

https://youtu.be/r9lFujHjRo8

https://youtu.be/qwfj4RTal0U

Hardware

Required

• M3 x 70mm Bolt
• M3 Washer
• M3 Locknut
• Spring (5mm diameter x 15mm length)

Recommended

• M3 x 8mm Length Bolt (x3)
  Attach lock ring without glue
• O-ring 12mm Outer Diameter 8mm Inner Diameter (x4)
  Gives lids a tighter fit

Optional

Add magnetic latch to hold cork

• Steel Dowel Pin 4mm Diameter 14mm Length (Or cut down a bolt to size)
• 6mm x 3mm Cylinder Magnet

Links

Since finding the correct hardware can be tricky, I'm providing links to the exact items I've purchased for my own prints. I can't guarantee these will be in stock, but I do know they worked for me.

O-Rings 12mm OD 8mm ID 2mm Width
https://www.amazon.com/gp/product/B07F329SW1

M3x70mm Hex Bolt Socket Head Cap
https://www.amazon.com/gp/product/B015A33SBE

M3 Pitch Black Nylock Nuts
https://www.amazon.com/gp/product/B07FRLRWD4

6×3mm Cylinder Magnets
https://www.amazon.com/gp/product/B07873ZCY4

5mm diameter x 15mm length Spring
https://www.amazon.com/Stainless-Compression-Springs-Silver-0-5x5x15mm/dp/B08952DV8C

52100 Alloy Steel Dowel Pin, 4mm Diameter, 14mm Long
https://www.mcmaster.com/52100-alloy-steel-dowel-pins/material~52100-alloy-steel

These are not affiliate links and I have no association with the sellers listed

Printing

The following parts need to withstand some force, so it's recommended that you print them with more perimeters and/or a higher infill:

• Interlocking Pin Top
• Interlocking Pin Bottom
• Screw
• Cork

I've personally found 30% gyroid infill with 3 perimeters to work well, however your results may be different depending on layer adhesion, printing temperature, filament quality, etc. Printing the cork in PETG will also result in a much stronger print.