Charles takes up a Hobby

Charles was a natural mechanic and had always been interested in clocks. He joined the National Association of Watch and Clock Collectors in January 1950 as member #819. A year later he became Chairman of the NAWCC Membership Committee - a natural post for an advertising man. Read a PDF from a 1951 NAWCC Bulletin on COT's initial membership efforts. While Chair of this Committee NAWCC membership increased dramatically - earning him some disdain from the "Good Old Boys" for the number of "ordinary collectors" he brought into their Association.

His job had one advantage in that he was able to spend a lot of time moving about New York city entertaining or meeting clients. He began to frequent the auction galleries looking for clocks. Auction galleries were to become an important asset in his horological future. While buying a few good pieces he concentrated on French and German clocks with movements he could use to practice repair techniques.

Once he had accumulated a large number of movements, his entrepreneurial nature kicked in again and he started a business - "Charles Terwilliger Old French and German Clock Parts". His stock of parts was acquired by cannibalizing his large stock of movements. His customer base was advertisements in the NAWCC Mart.

He began to frequent the U.S. Postal Service auctions for movements.

Whenever the post office paid the insurance amount for a damaged parcel the parcel contents were sent to a central location in New York. There they were put in large lots that were sold at public auctions.

There were plenty of lots of damaged clocks. Many were cheap electric clocks in broken cast spelter cases. There were also always a large number of 400-Day Clocks - most of which were broken (probably just the domes) when they were shipped from Germany by GIs who had bought them from Post Exchanges to send home.

By the mid 50's he had accumulated a large and organized collection of "modern" (post WW II German) 400-Day Clocks - at least one of each make and model he had found, as well as many older clocks. At this time collectors did not have much interest in torsion pendulum clocks so he was also able to purchase antique and unusual examples at the regular auction galleries. These older clocks formed the nucleus of the Horolovar Collection and the photographs found in the later editions on the Repair guide.

Charles was aware of the problems that made 400-Day Clocks unpopular with clock repairmen. They were poor timekeepers and the principal problems were associated with the suspension spring. Most of the German movements themselves were quite uncomplicated and well made.

There was no sense or order to the suspension springs available to the repairman. The clocks occasionally came with spare springs. These early springs were made of a steel or bronze alloy. The suppliers of clock repair items had no point of reference to differentiate between clocks.

Charles called on some resources he had maintained from his years at MIT. Tests determined that the currently available springs had an inconsistent modulus of elasticity. In other words the available springs would stiffen or weaken, some considerably, with changes in temperature. This was a primary source of the timekeeping problems.

Some more research provided an excellent option for a new alloy for suspension springs. One with a constant modulus of elasticity - Ni-Span-C.

Ni-Span-C is a nickel-iron-chromium alloy made precipitation hardenable by additions of aluminum and titanium. The titanium content also helps provide a controllable thermoelastic coefficient, which is the alloy's outstanding characteristic. The alloy can be processed to have a constant modulus of elasticity at temperatures from -50°F to 150°F (-45 to 65°C). Used for precision springs, mechanical resonators, and other precision elastic components. Standard product forms are round, strip, tube, pipe, and wire.

Data provided by the manufacturer, Special Metals.

It should be noted that the material did not require heat treatment to provide the desired characteristics.

Having selected a potential alloy, he sought a facility to manufacture the springs. He successfully approached the Waltham Watch Company, which became Waltham Precision Instruments in 1957. For more than a century, these companies operated in the same historic building in Waltham, Massachusetts and the suspension springs were drawn and rolled on the same machinery that was used to make hairsprings for the magnificent Waltham Watches.

The Ni-Span-C wire was first drawn through diamond dies to a specific diameter such that when rolled to a specific thickness the width of the resulting spring was always .016 inches. The constant width allowed assumptions about the effects of variations in thickness.

Now the experimentation began. He acquired some sample springs from his manufacturers and systematically installed them in the various clocks he had collected, including a number of rare and unusual clocks - First to see if they would work at all, then to see if they would keep time.

They did work and they did keep time.