I saw a toy like this to buy online naturally I decided to try and make one myself since I really love the idea of this kind of simple mechanism as a fidget toy.

note: you're going to need to print 2 of the cap pieces if you intend on printing this.

Update: A lot of people have been saying the tolerances are too loose. I'd just like to say all these things had to be printed on my school 3d printer - a Zortrax M300. It's calibration is not up to scratch and has many issues - and I designed it for my use on this 3D printer.