The sliding puzzle is in the last stages of design and at the beginning stages of fabrication. While not all the details are complete, the design for the pins and handle for moving the cogs is finished. This has been the biggest challenge and I will continue onto the full fabrication of a cogged panel. If works, then I will duplicate the fabrication for everything.

The pins are machined from a piece of round stock aluminum I pulled from the dumpster at school. When they hired someone to put handles on the gallery doors, these were the left over pieces that were tossed in the trash (there were at least 4 of them). I use a machinist or drill press vice to hold the round stock because it will twist in my fingers. 

To keep the aluminum flat against the bed of the band saw, flip the vice upside down with both jaws touching the bed.

After cutting the end of the aluminum on the band saw, I center it on my 1940 Montgomery Wards (mfg by Logan) Lathe using a four jaw chuck.

My first attempt at designing the post was using a single piece of steel for mounting the gears. 

After center drilling and facing the steel, I used a live center to steady it.

I machined the axle (long, skinny section on to the right), followed by the bearing's seat (this sits in the top layer of wood), and the end that sits in the bottom two layers of the wood panels. Then a parting tool cuts through the steel stock to remove the new part. It still needs to be turned around in the lathe, machined a bit more and turned back around to cut the 1/4 -20 threads.

Here are the parts laid out (lt to rt). Acrylic gear (not final material), nut, washer, a Boca Bearing and the steel post.

I used steel because I plan on using magnets in the base of the board so each panel snaps into place and fully engage each other. I was going to fabricate a handle of some sort but I did not like the balance of the piece. The piece is bottom heavy and when moving it from the top of the post, the whole piece wants to tip forward like a weeble wobble. I decided to modify the design in aluminum and steel while also breaking up its parts some.

I started with the lower half of the post. It will be threaded so I can used a bolt to join the two haves together with a carriage bolt.

The part on the left is the bottom section. The part on the right sits on top of the Boca bearing and spaces the handle (largest diameter section).

(Top row lt to rt) rare earth magnet, fully assembled post and gear on magnet, and end gear.
(Bottom lt to rt) 1/4 -20 nut, lower aluminum post, Boca bearing, gear, upper aluminum post, 1/4 -20 carriage bolt.

The side view shows the layers that will go in the wooden panels. The very bottom is just a steel plate for displaying these gears temporarily while being joined to the gear assemblies with rare earth magnets.

From here, I will construct the wood panels for these two gears, resolve any issues and finish its construction.