Chauncy Boardman Groaner Spring Clutch Repair

Discussion in 'Wood Movement Clocks' started by dgmcrm, Dec 1, 2016.

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  1. dgmcrm

    dgmcrm Registered User
    NAWCC Member

    Oct 1, 2009
    Retired electrical engineer
    Lexington, Virginia
    Country Flag:
    I recently acquired a Chauncey Boardman "Bronzed Looking Glass" Clock with a standard groaner movement. The only problem was the looking glass had been broken out transporting it to the shop where I acquired clock, and some time in the past the wooden minute arbor had been broken off where it attaches to the squared brass ferrule for fitting the minute hand.

    Upon investigating, it was apparent the minute arbor had been broken because the "time set" spring clutch friction was way too high when someone attempted to set the time. This is the first groaner I have worked on, but I was able to disassemble the wheel and spring clutch from the winding arbor. You can see in the photo that the three-pointed spring clutch had worn a groove in the wheel that transfers motion from the winding arbor to the minute arbor pinion.

    I decided to do two things: lubricate the groove that had been worn into the transfer wheel and reduce the spring force applied by the leaves of the clutch.

    I heated the wooden wheel with a hair dryer (careful to stay below Fahrenheit 451 :)) and then applied wax from a small birthday candle into the heated groove. As the wood accepted the wax I heated and added more until I felt enough had been applied for this experiment. See photo.

    I then reduced the tension that could be applied by the spring leaves slightly. See photo.

    Upon reassembly (and repair of the minute arbor). I found the clock can be easily set without over-torquing the minute arbor and yet the clutch pressure is enough to drive the minute part of the motion work.

    The clock runs and strikes well now with a temporary pendulum, but it needs a lot of cosmetic work, which I will attempt next. I don't know how long this wax-fix will last.

    I found R. Croswell's posting of April 2006, "How can I fix a jumpy clutch and spontanious striking?",
    useful is getting together the courage to attempt this project.

    DSCN1153.jpg DSCN1156.jpg DSCN1157.jpg

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