Discovered: Original Fresnel Lens rotation mechanism

Polishing a century of grime from one of the brackets of the original First Order Fresnel lens rotation mechanism.

Polishing a century of grime from one of the brackets of the original First Order Fresnel lens rotation mechanism.

Ever wonder how the giant First Order Fresnel lens rotated to produce that smooth, sweeping beam lf light?

The good guys at the US Coast Guard revealed the secret by sending us the old engineering drawings of parts of the original mechanism, which are still bolted to the 5th level ceiling.

Since that ceiling is being restored, we figured we’d take the mechanism down and clean it up, which we did this week at home.

Here’s how it worked: Every two hours the Keepers wound a 300-lb weight up a 50-foot tube using a hand crank. The weight was connected by a series of pulleys (pictured) and connected to a big clockwork device, which regulated the speed and drove a gear that spun the two-ton lens.

The system was converted to an electric motor long ago, but happily the Coast Guard left all the old stuff in place, which made it possible for us to tell the story.

 

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One Comment

  1. steve williams Neon Williams, Inc

    Dave,
    Just want to tell you the refurbishing you are doing
    is looking fantastic. To think we will all be able
    to look at history being kept and nourished by you
    for years to come is very exciting.
    Thank you for your hard work please pass this on to
    your crew and I hope you and your wife get to have
    wonderful times in the house.
    Sincerely
    Grace and Steve Williams

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