Internet Horology Club 185
What is the purpose of this blued spring?

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March 18, 2011, 14:55
Mason Stewart
What is the purpose of this blued spring?
What is the purpose of the blued steel spring in the attached photo of this recently acquired older chronometer? As a "newbie", I can't tell if it is original to the chronometer or not.

G Blackie Chronometer

March 20, 2011, 07:31
Chris Abell
From what I can see in the picture looks correct if it’s what I think it is really need better photo/s to be sure.
March 20, 2011, 15:16
William D. White
The spring is for the maintaining power assembly which keeps enough force on the train to keep the escapement and hands running during winding. Without maintaining power on a fusee timepiece, power would be completely lost during winding.

March 20, 2011, 20:03
Mason Stewart
Ah ha, that makes sense; thanks!
I've gotten conflicting advice on whether or not to keep the chronometers running, which I prefer, or to wind them only sparingly to protect their aging components. Also I I don't wind them daily, should them be kept fully wound, but not running, or be alowed to wind down? The Blackie chronometer seems to have some tension on it even when wound down. Advice appreciated.
March 20, 2011, 20:11
Tom Brown
On fusee movements, there should always be some tension on the chain. If there wasn't the chain would fall off the barrel or the fusee or both.

March 21, 2011, 14:56
Mason Stewart
Thanks. The clock repair guy, when checking this chronometer out and who maintains other fusee movement antiques said that this movement "felst like" it had tension on the fusee movment even when wound down--which he said was good. Does that make sense?

Also, is there a consensus on keeping wound and running viz-a-viz displaying them static?
March 21, 2011, 15:53
Chris Abell
Hi Walter,

This may help, If you look at the chain (and of course I am generalizing as many variations exist) if the watch is run down all the chain should be all on the barrel and the end of the chain hooked to pin at the bottom of the cone shaped gear if you touch the chain between the two you will feel tension, in the photo you can see the dial side and the ratchet an click (bottom of barrel) that after servicing you tension the chain, once set you never need touch it in fact the click is then tightened down so as not to release. On the right I split the two sections apart and you can see the mechanism William mentioned the outer spring is under tension and continues to provide power during the brief winding period and the upper tension is removed by the act of winding.

As for keeping it running, first you should have it professionally serviced and inspected you may cause or be causing damaged in in running it without, once serviced, unless otherwise advise by the watchmaker, there is nothing wrong in running daily for your own enjoyment, if you are looking at preserving it point of view I would once a month or so give it a part wind allowing it to run for a short period, if it was a pocket or wrist watch I would also advise changing it over from face up to face down after each monthly wind.
March 22, 2011, 10:20
Mason Stewart
Thanks. The explanation is enlightening and the advice makes really good sense. I hadn't thought about inadvertantly causing damage by running it without if first being serviced.

There is an person here in town who maintains old clocks and use to service chronometers off ships that were in port, but he said he hasn't done one in about 25 years. He said "you can't just dust them off and put oil on them" that to be serviced properly they had to be disassembled, each part carefully cleaned, and then reassembled, which was time consuming, very detailed work, and expensive. My question is, what is an average price one should expect to have an antique chronometer properly serviced?
March 22, 2011, 10:59
Chris Abell
Walter, he is correct these chronometers take a good deal of time to service correctly and of course if parts are needed they almost certainly will have to be made, finding a person who can service these is your first hurdle and by the sound of it you have that person. As for cost if you reasonably estimate he will take about 8 hrs+ work to service it correctly, plus time to test and make final adjustments, this should give you a idea. I would offer to pay for a estimate including full disassembly and inspection to find out if any expensive hand made parts are needed of course once apart if you go ahead with service most of the estimate will be absorbed in to the service cost.
March 23, 2011, 08:50
Mason Stewart
Thank you all!