Expert: William J Perkins - 12/20/2009

Question
I need a torsion suspension for a small Hermle/FHS movement. The movement does not appear to have a model or serial number. The front and back plates are about 6.5 cm tall, and the bracket from which the suspension hangs adds about 2.5 cm to the height of the movement. The remnants of the torsion spring suggest that the original length was between 9.5 to 9.75 cm from pin to pin. The suspension is 0.0024" (0.06096mm)thick and 0.0225" (0.5715mm) wide. Given the damage to the suspension and the small size of the surviving fragment, these dimensions are approximate. The crutch is missing as well.

Questions:
Model number of the movement?
Part number of the suspension?

Answer
I presume you are discussing a 400-day clock (anniversary clock).  Unfortunately the information given is not very helpful.  From what your description I would gather you need a replacement torsion spring unit.  Such units are available through many clock materials houses.  The units consist of, torsion spring, top block, fork and bottom block.  They are all precision assembled and are ready to install.  The problem is, we don't know the precise clock to order the parts for.  To make a proper determination I suggest you do one of the following.  1/  Go to your library and have them get you a copy of Charles Terwilliger's book; The Horolovar 400-Day Clock Repair Guide.  This book depicts, in actual size, the backplate of every known 400-day clock along with an actual size, torsion spring unit for every known such clock.  This book is the bible of clock repairers for such clocks.  The alternative to this suggestion is, 2/ Take the clock to a clock repair person who has a copy of this book and have him identify exactly what you need.  The book is essential to your quest.  Let me know how you make out on this.  Regards WJP