1) Purchase, Print and Prepare the Parts.
You will need 8 3mm diameter 1.5mm thick neodymium magnets for the two shelf halves.
I have attached a PDF file containing the list of printed parts which includes the part names, part counts, print settings and colors I used. If a color is left blank, I did not print the part. "Shell.3mf" is the dual extrusion file I used to print my shell halves. However, I've also included "Shell.stl" (a single extrusion shell), "Shell Pink.stl" (the shell body itself) and "Shell White.stl" (the decorative banding). Use "Shell.stl" to print a single color shell half. While I did not try it, it may be possible to print "Shell Pink.stl" and "Shell White.stl" then glue them together.
This model uses M6 by1 threaded assembly and may require a M6 by 1 tap and/or die to clean the threaded components.
2) Assemble the Base.
Place both "Gear Yoke (12 teeth).stl" into the base as shown. Check to make sure both gears rotated freely.
Place "Gear Knob (12 teeth).stl" into the base as shown. Again check for free gear rotation.
Slide "Knob.stl" up through the bottom of the base and thread it into gear knob. Do not over tighten, and make sure the knob easily rotates the gears.
Slide one "Yoke.stl" into the the yoke slots in the base, then use a small screw driver to lift the leading edge of the yoke just enough to allow the yoke to slide over the pin on gear yoke, then continue sliding the yoke towards the center to allow the yoke slot to surround the pin as shown. Once the yoke is positioned, check to make sure the knob easily rotates the gears and slides the yoke. Repeat this process with the remaining yoke.
Rotate the knob until both yokes are fully extended (away from center, close to outside edge). Position one "Gear Yoke (12 teeth).stl" in the base as shown and secure in place with one "Axle Gear Shell.stl". Rotate the knob to make sure the gears and yoke move easily. Repeat this process with the remaining gear yoke.
Rotate the knob until both yokes are fully extended and both gear yoke pins are vertical, then position "Top.stl" over the base assembly as shown. Flip the assembly and rotate the knob until the knob holes align with the holes in the base. Finally, thread the four "Bolt Top.stl" into the holes in the base as shown. These bolts need to be fully threaded into position in order to allow clearance for the knob, but do not over tighten. Check again to make sure the assembly rotates freely.
3) Final Assembly.
Rotate the knob until the two gear yokes are fully extended.
Install the 8 neodymium magnets into the two shell halves, making sure the magnets are installed such that the shelf halves attract each other.
Press one of the shell halves onto one of the gear yoke pins as shown. The top of the gear yoke pin should be flush with the top of the shell halve mounting hole Repeat this process with the remaining shell halve.
Thread "Ring Tower.stl" into the center hole in the top as shown.
Test the completed assembly by rotating the knob. Note the knob can be rotated in either direction to open and close the ring box. Since the threads on the knob and knob gear are right handed, you may wish to apply a small dot of cyanoacrylate glue between the threads of knob and knob gear for counter clockwise rotation of the knob.
That's how I made Pseudo Secret Ring Box.
Hope you enjoy it!