Introduction: Bolt-Nut Puzzle - 3D Printed

By
About: I love to craft and my sons and grandchildren keep me going!

This project is based on the publication https://www.instructables.com/Twin-Nut-Puzzle/ by AtulV15. Thanks for posting this nice little projekt!

It drives everyone who does not know the solution to despair and abandonment! 

While looking for a little present for a visit to relatives with two kids, ages 8 and 10, I came across the "Twin Nut Puzzle".

  • The task of the puzzle is to guide the nut along the rope over to the right loop 😮 to the screw and then screw it up.

Then I read the comments and saw framakers' post. I liked the idea of replacing one of the two nuts with a matching screw. I agree that it makes solving the puzzle much more attractive.

However, drilling vertically through a metal screw is not everyone's cup of tea, nor is it easy to do.

A good and relatively easy way to solve the problem with the pierced screw is 3D printing ... provided you own a 3D printer!

To implement the idea, I decided to prepare this small project completely for 3D printing.

Supplies

For this project you need:

  • bolt-nut puzzle_base.stl
  • bolt-nut puzzle_bolt_M12x18.stl
  • bolt-nut puzzle_nut_M12.stl
  • cable ties (2x)
  • rope (620 x Ø 4-5 mm)
  • pliers or scissors

Attachments

Step 1: Printing

First you have to print the following files:

  • bolt-nut puzzle_base.stl
  • bolt-nut puzzle_bolt_M12x18.stl
  • bolt-nut puzzle_nut_M12.stl

Print Settings

  • printer brand: Prusa
  • printer: MK3S / Mini
  • supports: No
  • resolution: 0,2
  • infill: 15% ; nut and bolt 50%
  • filament brand: Prusa; ICE; Geetech
  • filament color: Galaxy Black; Young Yellow; Silky Silver
  • filament material: PLA

Remark: As all parts are designed to fit very precisely, it may happen that you have to rework one or the other part a bit with sandpaper and/or cutter due to different dimensional accuracy of the printers and the different behavior of the filaments.

Step 2: Insert Rope - Secure Ends

After the three parts are printed, you need for the next step:

  • rope (620 x Ø 4-5 mm)
  • cable ties (2x)
  • pliers or scissors

Now you have to insert the rope as shown in the pictures.

Before you put the left end of the rope into the left hole, do not forget to insert the nut. Take one of the cable ties. Prepare a loop and place it about 5 mm from the end of the rope and pull it tight. Cut off the long end with pliers or scissors.

You can, of course, tie a knot. In that case I would cut the rope about 3-6 cm longer, depending on how thick the rope is.

Next you need to put the bolt on the right side of the rope. Make sure that you insert it with the threaded side. The screw head must be oriented to the base.

Then - as on the left side - insert the end of the right rope into the right hole and secure the end again with a cable tie.

That's it!

Step 3: Solution

As for the solution of the puzzle, I would like to refer you to the page of AtulV15.

https://www.instructables.com/Twin-Nut-Puzzle/

He has described it very well. I have nothing to add to it!

However, I still have to give one hint:

for the solution you should only move the nut, because, due to the size of the screw, the solution process would be more difficult.