Here's a look at how I built the motor that will "power" the celestial orrery:
The orrery from the Celestial Hurricanum will be positioned on the upper wooden platform, but it needs a motor to power it. The Chaos Defiler sprues that I've had in my parts box for ages finally got its time in the sun. The arms have a lot of nice gears and pistons that are perfect for kitbashing random bits of machinery. I've also got some Land Raider weapon parts, and decorative metal gears from the craft store, and old metal Dreadnought feet and weapon mounts.
After test-fitting various pieces together, I settled on the Defiler weapon arm, mounted below half of a heavy bolter. I scraped off the Chaos icon and replaced it with a Skaven shield icon and rivets cut from styrene rod. The end result resembled a motor with a connected drive shaft. The flat side of the bolter fit nicely between the support beams on the underside of the platform.
That "drive shaft" needs something to connect to, so I chipped up one of the Defiler legs.
I cleaned up the part, distressed the edges of the metal framing, and etched a Skaven icon into it.
As the motor was coming together, I envisioned the drive shaft connecting to the gears of the Defiler leg, which would be positioned under the orrery.
I carefully sliced a groove into the Defiler leg, and inserted one of the metal gears into it.
Because the opposite side of the leg was hollow, I needed to cover it with thin styrene card so the portions of it that were visible through the wooden planks would appear solid.
I also embellished the gear (in the top right of this image) with a "hubcap" sliced off of the Defiler's ankle joint, and topped both gears off with bolts cut from styrene hex rod and round rod. For the drive shaft, I cut a segment out of a lascannon and inserted a length of styrene rod through the center.
This was glued onto the Defiler arm, and a gear was attached to the end, interlocking with the gear on the Defiler leg.
I capped off the gear with another nut and bolt.
One final detail was to fill in the gap on the bottom of the motor. In the end, I settled on more gears– The large plastic gear cut from the Defiler leg, and my last small metal gear.
The mount for the orrery was made from an old Imperial Guard Tarantula gun mount. I also used one of the toes cut from a metal dreadnought foot.
The mount was positioned in line with the gear on the underside. The feet were trimmed and styrene bolts were added to "attach" it to the wooden deck. I covered the point where the leg was removed with the dreadnought toe.
With the motor and mount out of the way, I can move on to building the orrery itself.