Anniversary suspension spring guard
The early 400-day clocks especially those produced prior to 1908 do not have a suspension spring guard. Moving such clocks from a cupboard or display cabinet where it is not possible to lift off the glass dome to unhook the pendulum would cause the pendulum to swing wildly with the possibility of damaging the suspension spring or breaking the glass dome.
While replacing the suspension spring or the standard size glass dome may not be much of a problem, however to find an odd size replacement such as an oval-shaped dome, figure 1, is not easy—to say the least!
The risks of suspension and glass dome damage can be greatly minimized by the installation of a simple home-made suspension guard on to clocks that were not originally provided with one. This can be accomplished by cutting a U-shaped piece of plastic from a discarded packing container such as used for small parts, computer software, electrical components etc. These are know as blister packs or thermoform packs, are made from clear pvc which is rigid enough to do the job and flexible enough to be cut with ordinary scissors.
The U-shaped piece, about 1in square, should be cut approximately as shown in figure 2 and when installed as shown in figure 3.
To install the piece, simply loosen the knurled hand screws that hold the movement to its support plate, tilt movement slightly forward, and insert the open end of the ‘U’ between the movement and the support plate, being sure to centre the suspension spring in the opening provided. Re-tighten the movement mounting screws and this will clamp the guard piece firmly in place. The whole task can be completed in less than 10 minutes.
With the DIY guard piece in place, the movement of the pendulum will be restrained and this will significantly reduce the possibility of damage to the suspension spring or the glass dome.
Mun Chor Weng, Singapore
