Main spring replacement is something you should consider as part of a regular e.g. 10y yearly, service on a mechanical clock. Over time even the best springs will lose thier power as they are wound and released. If you are thinking of getting your clock serviced because it keeps stopping unexpectedly then think about getting the main spring done at the same time. Yes it does double the cost from about £60 to over £100 but the spring itself accounts for the majority of this higher service cost. Overall, if you plan to own the clock for your lifetime its the best way to go about things and actually cheaper than cleaning and spring replacment as two different services delivered on two jobs.
The pics here show a relatively modern 14″ bracket clock. Its a beauty for a modern clock and really has gravitas in much the same way as a grandfather clock does. Its become another clock on my wish list but that is already impossibly long as I tend to bond a bit with all the clocks I work with.
The pics show the movement re-assembled ready for its new spring and top plate refitting. Note the excellent condition of the movement overall – the point here is that it can look as clean as the day it was sold but over time the spring will wear down. This clock was running consistently for 4 days on an 8 day spring and fading over time. If you have the same problem you know who to call!.