Locking Thread Puzzle – Trò chơi ghép ren có khóa

I needed to create something where a group had to figure out to work together and rely on each other to solve. It consists of 2 parts that are locked together. One part has a threaded shaft and the other has a threaded hole. But there are 7 different threads so only one pair will fit together. When the correct shaft is screwed all the way into the hole, it releases the clips allowing the 2 parts to separate revealing a rolled up bill inside. The idea is each person has to find the 2 people who have the matching parts.

Also each set has a matching ring screwed onto the shaft, and a plug screwed into the hole. These are just red herrings to confuse. If the ring isn’t removed the shaft won’t screw far enough into the hole to release the clips.

The attached pictures include cutaway drawings to show how it works inside.

I am including .STL files for 7 rings, 7 plugs, 7 male parts, 7 female parts and 1 locking clip. The clip needs to be printed 7 times. The clip should be printed on its side otherwise the thin arms could break between layers. Also it is the only part that  needs to be printed with support. The male parts should be printed vertically with the shaft down and the open end up. I recommend a good raft base to be sure it adheres well to the build plate. The female parts should be printed with the slots down and hole up.

Press the locking clips gently but firmly into the open end of each male part. It might help to have them screwed into the female parts for stability during this. A block of wood approximately 3/4” square is helpful to press it in. Also the beveled edge on the ring might need to be filed down to help it slip past the retaining lip. Once in place it should stay locked. But a couple drops of super glue should help hold it in place if necessary.

Next, insert the locking clips into the slots in the female part. Be sure the threads on the 2 parts are different or you won’t have the right part to screw into it. If that happens you can stick a pen into the hole to release the clips. Unfortunately, someone with thin fingers will be able to do this. I tried to size everything so this couldn’t happen.

This table lists all of the .STL file names along with the thread information.

filename

part

threads per inch

thread direction

matching part

matching ring nut

matching plug

1F 45R.STL

female part

4.5

RIGHT

2M 45R.STL

Plug 45R.STL

2F 5R.STL

female part

5

RIGHT

3M 5R.STL

Plug 5R.STL

3F 6R.STL

female part

6

RIGHT

4M 6R.STL

Plug 6R.STL

4F 45L.STL

female part

4.5

LEFT

6M 45L.STL

Plug 45L.STL

5F 5L.STL

female part

5

LEFT

7M 5L.STL

Plug 5L.STL

6F 4L.STL

female part

4

LEFT

5M 4L.STL

Plug 4L.STL

7F 4R.STL

female part

4

RIGHT

1M 4R.STL

Plug 4R.STL

1M 4R.STL

male part

4

RIGHT

7F 4R.STL

Nut 4R.STL

2M 45R.STL

male part

4.5

RIGHT

1F 45R.STL

Nut 45R.STL

3M 5R.STL

male part

5

RIGHT

2F 5R.STL

Nut 5R.STL

4M 6R.STL

male part

6

RIGHT

3F 6R.STL

Nut 6R.STL

5M 4L.STL

male part

4

LEFT

6F 4L.STL

Nut 4L.STL

6M 45L.STL

male part

4.5

LEFT

4F 45L.STL

Nut 45L.STL

7M 5L.STL

male part

5

LEFT

5F 5L.STL

Nut 5L.STL

Plug 45L.STL

plug

4.5

LEFT

4F 45L.STL

Plug 45R.STL

plug

4.5

RIGHT

1F 45R.STL

Plug 4L.STL

plug

4

LEFT

6F 4L.STL

Plug 4R.STL

plug

4

RIGHT

7F 4R.STL

Plug 5L.STL

plug

5

LEFT

5F 5L.STL

Plug 5R.STL

plug

5

RIGHT

2F 5R.STL

Plug 6R.STL

plug

6

RIGHT

3F 6R.STL

Nut 45L.STL

ring nut

4.5

LEFT

6M 45L.STL

Nut 45R.STL

ring nut

4.5

RIGHT

2M 45R.STL

Nut 4L.STL

ring nut

4

LEFT

5M 4L.STL

Nut 4R.STL

ring nut

4

RIGHT

1M 4R.STL

Nut 5L.STL

ring nut

5

LEFT

7M 5L.STL

Nut 5R.STL

ring nut

5

RIGHT

3M 5R.STL

Nut 6R.STL

ring nut

6

RIGHT

4M 6R.STL

tabs.STL

locking tabs