Internet Horology Club 185
Waltham 645 21j Mainspring

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August 16, 2018, 16:54
Gary Orris
Waltham 645 21j Mainspring
Good evening to you all, I have just joined and can't believe how much information is here.
I own a Waltham 645 serial : 19034455 and whilst winding it up 2 weeks ago I heard a whirring noise and there was no tension left as I wound.Suspecting that the mainspring had broken I removed the barrel to check.The mainspring had broken where the loop attaches to the arbour.
My question is : Is this dark blue/black spring likely to be the original mainspring ?
Regards ..... Gary


August 16, 2018, 17:01
Gary Orris
Oh and this is the watch ...... It is one that I wear most days to work.
I bought it on the infamous auction site about a year ago for £52 (Approx $66). It keeps very good time and had never let me down until the mainspring broke.
Regards ..... Gary.

Waltham 645

August 17, 2018, 11:23
Michael Kosinenko
Hi Gary, I don't think that there is a way to tell if the spring is the original one, as there are still new old stock blue mainsprings around today that could have been installed at any time.

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August 17, 2018, 16:10
Gary Orris
Thanks for the reply Mike.
I did think that it may have been replaced before but I suppose there's no way of really knowing.
I fitted a new mainspring today, a silver coloured spring and the watch is now running again.
The mainspring I removed feels very weak & flimsy when compared to the new one.
Here's hoping.
Regards .... Gary.
August 17, 2018, 20:10
Bila Wirriganwalters
Those 645 Grades are the perfect workhorse Gary, great to work on and nice to carry.
August 18, 2018, 13:03
Brian C.
Gary, you did the right thing replacing a steel m/s with a white alloy unbreakable one, especially where you wear it everyday.
August 18, 2018, 16:59
Gary Orris
Thanks everyone.
The 645 has been running all day with the new spring. It is gaining approx' 2 minutes an hour at the moment, I'll let it run fully down then wind again.... do this a few times and see how it settles.
Regards ..... Gary.
August 18, 2018, 19:56
Bila Wirriganwalters
Is that 2 mins an hour Gary or 2 minutes a day. If it is 2 minutes an hour it is not going to come good, I would be have a close look at the watch to see it something is amiss.
August 19, 2018, 23:38
Ernest Thiessen
e mainspring I removed feels very weak & flimsy when compared to the new one.Here's hoping.

Maybe the new spring is too strong for the movement.
August 20, 2018, 17:35
Gary Orris
Thanks for the replies.
I let the watch run down and then wound fully over the weekend.
Then, this morning, at 7am I wound the watch fully and set the time to a quartz watch I own. I've just checked the time after 15 and a half hours and it has lost approx' one minute so looking fairly good.
And to celebrate I've just bought a new waistcoat to wear the watch with .... Just got to get my son to make a new button hole for the watch chain.
I'll keep my eye on the time keeping for the next week, so here's hoping it will hold up.
Regards ....... Gary.
August 20, 2018, 17:38
Gary Orris
Oh and thanks for your input Bila,
I got the details wrong big time there. Eek
Regards .... Gary.