Archive for timepiece

Custom Clock Case for a Charles Frodsham Regulator

Posted in Artisanal, Furniture Making, Woodwork, Woodworking with tags , , , , , , , , on February 11, 2014 by johnwiggers

We received an inquiry a few months ago from a collector and restorer of antique clocks. This fellow had a rare 19th Century Charles Frodsham timepiece, and he was looking to have a proper cabinet made to showcase the craftsmanship of the mechanism.

It was decided to build the cabinet out of Mahogany, and finish in a traditional French Polish. Some non-traditional details were added, including a removable crown to allow for easier adjustment of the clock mechanism. A portal window was also added on the left side to make it easier to view the inner workings of the clock.

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We completed the woodworkIng portion of the project with relative ease. The bigger challenge came from building the layers of shellac necessary for the French Polish finish. We opted to use a natural amber shellac dissolved in ethanol to a 1-1/2 lb. cut. Multiple layers of this finish were then applied using cheesecloth.

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After allowing for the base coat to thoroughly dry some dark brown powdered stain was then sprinkled onto the surface and rubbed in with additional coats of shellac.

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By the time about 20 layers of shellac had been applied it was apparent that more work would be needed to fill the pores of the wood.

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Fine Rottenstone was then rubbed in with the shellac, and I quickly learned that it is possible to apply too much Rottenstone.

The excess material was carefully washed off and burnished back with ethanol, and the final layers of shellac were then applied.

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After lightly sanding with 2000 grit sandpaper and rubbing with 0000 steel wool the finish was then polished so that the cabinet could be readied for assembly.

Special thanks to Alfred Sharp of Alfred Sharp Museum Quality Furniture for mentoring us through some of the trickier nuances of the French Polish finish, including the ‘Rottenstone Incident’.

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Our client was thrilled to receive the cabinet, and he described the workmanship as “superlative”.

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The butt hinges and the English half mortise locks were crafted from brass.

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The above image shows the half mortise lock detail.

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This is the detail of the portal window on the left side of the cabinet.

It was evident that an exceptional level of craftsmanship went into the making of this mechanical timepiece. This prompted me to learn more about who Charles Frodsham, the maker, actually was.

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What I discovered was that Charles Frodsham is regarded as one of England’s most renowned clock and chronometer makers. This particular clock is one of his better timepieces, and it was made sometime between 1850 and 1870.

This clock is actually known as an astronomical regulator because it is crafted to the most exacting standards of precision. The style of its dial evolved from the earliest days of astronomers wanting to be able to more accurately track seconds and minutes of time. This design would later become a favourite of the wealthy who wanted the very latest/newest/best clock.

Part of Frodsham’s legacy stems from the fact that he published many papers discussing the nuances of how to mechanically keep a precise measurement of time, including the effect that electromagnetic fields of the Earth had on the movement of metal in timepieces. He was also cognizant of the effects of temperature, and how warmer temperatures would expand the metal on pendulums, thereby lowering the position of weights and slowing the clock movement which, in turn, would adversely affect the time measuring accuracy of the timepiece.

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To compensate for this he incorporated mercury into the pendulums of his regulators so that the mercury could expand with the heat and raise the position of the weight in the pendulum in a manner that would offset the simultaneous lowering of the weight due to the expansion of the pendulum rod.

Although Charles Frodsham was not the first to use mercury in pendulums for temperature compensation (George Graham first discovered this in the 1720’s) Frodsham did develop an improved design that ended up under patent.

Charles Frodsham’s preeminence in the world of horology coincided with the rise of the Industrial Revolution. In 1842 boatloads of cheap, mass produced clocks from New England began to flood global markets at the seemingly improbable price of $1.50 each. Over the next 20 years, in part because of this American competition, the British clock industry declined to near extinction.

Because of its distinguished reputation at the upper end of the market Charles Frodsham & Co. did manage to survive this onslaught of cheap product and steadily grow their business until the onset of the First World War. According to this recent article in QP Magazine a group called The Worshipful Company of Clockmakers honoured the legacy of Charles Frodsham & Co. Ltd. by presenting a reworked Frodsham fusee mechanism to Her Majesty the Queen in celebration of Her Diamond Jubilee in 2012.

Charles Frodsham & Co. Ltd. is currently located at 32 Bury Street in London, UK where they are enjoying more than 180 years of continuous horological trading. They also have workshops and a small manufactory in East Sussex where they undertake conservation and restoration work on stock and clients’ pieces, and make modern technical timepieces.

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