Spin-head Trick Box

I came across an Instructable 'Trick Opening Box' by Fathomlis, and found it interesting to work on.
Through that, I came up with a box with the same mechanism but a different design.
The mechanism works on the centrifugal force. You need to spin the box to open it.
It takes a few tries, but it will open.

This box will act like an invite/gift article to people, with an item stored in the box.

Step 1: Materials Used

Very few materials are used to make this box :

1. 5mm MDF
2. 1.5 inch nails
3. Fevicol SH

Step 2: Plans and Laser Cutting

Once I knew my dimensions, 3.5inches x 5.25inches x 3inches, I made my plans on Illustrator, to cut the pieces out on the laser cutting machine.

Once I had my pieces, I had to assemble them.

Step 3: The Mechanism

For the mechanism, I required a good amount of time to figure it out along with the dimensions of both, the nails and the MDF strips.

I stuck two sticks with holes in them, and after drying, using a 2mm drill bit, cleared out the glue from the holes if there was any.

REMEMBER : THE HOLES HAVE TO BE BIG ENOUGH FOR THE NAIL TO PASS, BUT NOT THE NAIL HEAD.

Step 4: Attaching the Mechanism to the Base

After calculations, I stuck the thicker sticks (the ones with holes), on two separate bases, equidistant from the center but on the OPPOSITE side on each base as in the picture.

I then stuck the single sticks 7mm from the ends.

REMEMBER : THE NAILS ENDS SHOULD PASS THROUGH BOTH THE STICKS IN THE CENTER TO MAKE THE LOCKING MECHANISM.

*The nail head should be towards the side of the single stick.

Step 5: Adjustments

I did these adjustments in the later parts of assembling the box.

The problem was that the nails would tilt and come out of the holes. To avoid this, I stuck two more strips ahead of the pre-stuck strip.

TO AVOID THIS : STICK THE SINGLE STICK APPROX. 12-15MM FROM THE END.

Step 6: Assembling the Outer Box

After that, assembling the box was pretty easy.

The sides were stuck and then held tight with the help of of masking tape until the glue dried.

Step 7: The Top and the Knob

The top piece was cut with an engraved circle in the center so that I could place the knob right in the center of the sheet.

The design was engraved, the circle was cut, stuck on another cut circle, and then finally stuck on the top base.
The top was then stuck on the inner box.

Step 8: Final Finish

The final step is to sand the whole box, make soft edges (fillets) and clear out any scratches etc.

Step 9: Asssembly

Finally, assemble the box and tilt the box so that the nails interlock.

To open it give it a spin or two.
If you are facing any problems, fix them by making minor adjustments.

Step 10: It's Ready

Now, put something in the box, tilt it and then gift it to someone, and watch them scratch their head trying to figure out how to open it!

Step 11: Note : a Change

Since the box was experiencing problems, i.e. it was taking a lot more spins than expected to open, I removed the number of nails.
I left only two nails on either side (4 nails in total), so that the box could unlock in two-three tries once the box is spun correctly.