| Clocks Magazine tips | November 2002 |
Working with mainsprings
The movement and refitment of original or replacement mainsprings is fairly well covered in various horological textbooks. I will ignore the manual methods often adopted - in other words winding in by hand and plier withdrawal - both of which are not recommended. Those who persist say to me that this is the way they have always done it! I point out that they are 'scraping' the barrel edge which will ultimately lead to degradation of the barrel, quite apart from mainspring distortion.There are various types of mainspring winder available. The item I have used successfully for many years is that of the Phillip Walton pattern. Prior to this I used the Swiss Bergeon set. Dealing with the good quality Trifix springs which I now use as standard, some people say they are far too strong for any given clock.
It is quite easy to adjust for any particular barrel by slightly reducing the height or thickness to give original power provided by the removed springs. However, a new Trifix spring, particularly if provided and encompassed within a steel ring, presents a problem. For small springs it is quite easy to put them in a large lathe chuck which can then be slightly closed thus enabling the securing ring to be removed. The chuck can then be gradually unwound with the spring expanding, enabling it to be secured by any conventional method.
However, the Picard Ltd mainspring winder is very economically priced and consists of eight Swedish steel barrels ranging from 18mm ID to 67mm ID. This will accommodate most clock springs, the subject spring being mallet-tapped into the barrel then wound out into a suitable retaining cloth. An old substantial pullover is ideal. Spring release/expansion is immediate without danger or damage. Such new springs always require cleaning and re-lubrication followed by rewinding using conventional mainspring winders.
J N Bartlam, UK
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