Restoration: Part 5

This is the moment of truth.  If the watch or clock has been properly assembled, and all the parts are in their proper positions, the timepiece will start to tick.  The next few steps in the restoration process really separates the amateur from the professional.  The proper adjustment of the hairspring, the balance staff, the roller jewel, banking pins, and regulator are all critical.  In a watch the first step is to properly poise the balance wheel, especially if the restoration required the installation of a new balance staff.  The watch maker accomplishes this by placing the pivots of the balance wheel on a poising tool.  The parallel ruby jaws of this tool provide a level and perfectly smooth surface for the pivots to rest on.  If there is a heavy spot on the perimeter of the balance wheel it will cause the wheel to revolve on the poising tool indicating where the heavy part of the wheel may be.  Just like balancing a tire on an automobile with small lead weights that can affect the true running of the tire, the watch maker uses very small weights to bring the balance wheel into a poised state.  He uses tiny little gold washers that are place under the heads of the screws on the perimeter of the balance wheel.  These washers are rated in terms of seconds per day as to how they affect the overall timing rate of the watch.  The proof of the pudding is the fact that no matter how it is placed on the poising tool, after being properly balanced, it will not favor a heavier or lighter portion of the wheel.  Once the balance wheel is properly poised the watch maker can place it into the watch and put it into action.