Repairing an American No. 2 Mantel Clock, Fourth Installment
In the third part of our series on servicing the Sessions American No. 2 mantel clock, we delve into the final steps, including bushing work, re-assembly, testing, and mounting the movement back into its case.
The Bergeon Bushing Machine, a staple tool in any horologist's arsenal, plays a crucial role in this process. The reamers that come with the machine are specifically designed for repair and maintenance of tall-case clocks.
The main purpose of these reamers is to precisely enlarge or true up pivot holes in the clock plates after worn bushings have been removed. This process ensures a proper fit and alignment for the new bushings, facilitating the installation, and preparing an accurately sized and centered hole.
Enlarging worn pivot holes to the exact size needed for new bushings is essential for the smooth rotation of the shafts and the longevity of the repairs. Additionally, cleaning and truing the bushing seat within the clock plate eliminates any irregularities or oval wear, further contributing to the movement's precision.
Tall-case clocks, with their large and deeply set plates, require reamers that provide very accurate hole sizing with minimal material removal. This helps preserve the original structure as much as possible, maintaining the geometric and functional integrity of the clock movement.
The author, in this instance, measures the diameter of the pivot using a micrometer to select the correct bushing for the escape wheel pivot, which has a depth of 2 mm, an outside diameter of 3.5 mm, and a pivot hole of 1.5 mm.
The author also uses the Bergeon Bushing Machine to install the bushings, testing the bushing on the pivot for fit before positioning it over the pivot hole and seating it using a small hammer. To coax the pivots into their respective holes during re-assembly, the author uses a pivot locator tool.
The author checks the fitment of the motion works bushings/pivots by assembling all the wheels on both sides and checking for smooth action. After re-assembling the mainsprings, wheels, and levers, and re-attaching the back plate using five plate screws, the author tests the clock for proper functioning.
This series is part of a larger exploration of the servicing of the Sessions American No. 2 mantel clock, a well-known American clock manufacturer, whose Type 89 movement was produced between 1900 and 1938. For adjustments made during the repair process, the author references Steven Conover's Striking Clock Repair Guide.
In the previous parts of the series, cleaning and mainspring servicing were covered, setting the stage for the meticulous bushing work that ensures the longevity and precision of this traditional mechanical clock. Stay tuned for the final installment, where we'll discuss testing, mounting the movement back into its case, and the final adjustments that bring this beautiful timepiece back to life.
- The author mentions the need to use a small hammer when installing new bushings into the clock, suggesting that clock repair involves not only technology like the Bergeon Bushing Machine but also traditional gadgets.
- Smart-home devices may not require the meticulous bushing work and re-assembly as vintage clocks, but repairing these large, traditional mechanical clocks like the Sessions American No. 2 mantel clock requires a deep understanding of technology and its historical evolution.
- In the final stages of the repair process, the author tests the smart-home devices' contemporary clock movements for proper functioning, showing that even in the era of precise smart-home technology, vintage clocks like the Sessions American No. 2 mantel clock still require careful maintenance and repair.
