Friday, November 12, 2010

Criterion Dynascope RV-6 Project: "Disassembly and Decisions"


After getting the scope home and performing a deeper inspection of the various components, it was obvious that this project was going to require a complete overhaul.

Rust had infected virtually every oxidizable surface including all hardware, the whole interior and exterior of the pier, and both axes with particularly bad pitting and corrosion covering the declination axis and its various collars.

Worse yet, the declination axis was actually frozen in place, apparently corroded so badly that it refused to rotate in its housing.

It was clear that the only way to approach this project was to completely disassemble the scope down to independent parts, remove the rust, scour away the grime and lose paint, replace hardware that was too far gone, and completely repaint and re-assemble.

After making a quick run to the hardware store for a few hex keys, some cleanser and an ample supply of naval jelly, I started the disassembly working first on the clock-drive then the axes and then the pier.

Most hardware was still functional coming lose after a little work but a few screws, namely the ones holding the mount head to the top of the pier and the various collars to the declination axis, refused to budge.

Rather than stripping the hex screws, I decided to leave these troublesome parts alone and then revisit them again after a few courses of naval jelly had removed most of the rust that was preventing them from turning as they should.

The declination axis was a bit more concerning though as I could not tell if what was causing it to seize was a lot of corrosion inside the declination "T" housing or if there was just a little near the edges but with this too, I resolved to delay my concern until I had removed as much rust as I could.


The clock-drive looked surprisingly clean given that it had been submerged in water on and off for better than two decades but the motor was clearly suspicious with corrosion coming from the location of the power lines.

It seemed pretty likely that the motor was dead, a fact that I confirmed later after its removal, but the other parts all looked to be in pretty good shape with some minor rusting on the hardware and serious grime (possibly old grease) on the worm gear.

I took care to take many pictures along the way in order to document the proper placement and location of all parts as well as placing all small parts in the cells of an empty egg carton with each cell clearly labeled in order to identify the main component that they were associated too.


With the clock-drive removed, the RA axis slipped out from its housing still connected to the frozen declination axis which, for the time being, I would treat as one single troublesome part.

Removing the large hex bolt that held the mount head to the pier took some doing as it was firmly rusted in place but a slight jerky back and forth movement of the hex key eventually worked to break this bond.

After removing the "lunar lander" feet from the pier, and removing all other lose hardware from all parts, the initial disassembly was complete.

Next up: "Naval Jelly and Elbow Grease"

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