- Topics Started: 85
- Total Posts: 1536
If it is a riveted loop end mainspring you will have a bit of a job to shorten it and then re-rivet the loop if you have not done this before. I would think 11″ might be too long but what I would suggest, if it is not a customers clock, is to try it as it is, worse case scenario is that the extra 11″ of spring will not allow it to unwind quite as far so instead of running for 8 days it might only run for 6 or 7, unless it is a 30 hour clock and then it might only run for 24 hours or so, these are just estimates, until you try it you wont know but you will not do any harm to the clock installing them as they are. If you find the clock is not running for as long as you would wish then you will need to look at shortening them.