jump spring for an hour wheel

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Submitted by Nick W. on June 11, 2019 - 3:10pm

I own a beautiful White Prince jump hour Bulova, but unfortunately, my watch repairman cannot find a replacement for the broken jump spring for the hour wheel.  I realize it's a bit of a longshot to ask for one here, but figure it can't hurt.  The movement is a 10AT, 15 jewels.

Secondarily, I might also be interested in an original hour wheel.  The one on my watch is a reproduction, which is fine, but if someone has an original that they're willing to part with, I'd be interested.  Of course, this is somewhat moot, if I can't find a jump spring.

Thanks,

Nick

 

mybulova_admin
Posted June 11, 2019 - 10:44pm

Nick a photo of the spring if you have one handy might help.

Reverend Rob
Posted June 11, 2019 - 11:23pm

This was a popular design in the late Twenties and through the Thirties, so there are quite a few other companies that produced these as well. Pocket watches had this popular complication back in the mid 1880s.

The trick would be to find one that uses the same ebauche that Bulova used, chances are fair that the jump spring would be the same or at least usable. (FHF ebauche)

I got an eyeful a few years back when a customer showed me what at first glance appeared to be a White Prince, and I was shocked to see that the watch was an Audemars Piguet, which of course, is NOT the same as the Bulova, lol. 

The more common watch companies were Mido, Ralco, and Cortebert. I mention the latter because despite being a movement manufacture, it wouldn't be the first time I looked inside such a watch and found something not made by them. 

LeCoultre also made a jump hour watch, as did Cartier. (Tank á Guichet)

Some of these are very plain, but some are enamelled and/or highly decorated and fetch high prices, even the Bulova ones, being a bit scarce, are going high.

Nick W.
Posted June 13, 2019 - 9:47am

Good morning.

I just received photos from my watch repairman, this morning.  He reports that the length of the jump spring is about 11.3 mm.  Hopefully, this will be helpful in finding a replacement.

The photos also include the reproduction hour wheel.  Not a bad job at all, I think, and I'm happy to live with it, but if someone can offer an authentic replacement, I might be interested.

Thanks,

Nick

Nick W.
Posted June 17, 2019 - 5:20pm

I may have tracked down a jump spring for a 13AT movement; I'm still waiting for particulars from the dealer.  Does anyone know (or have an educated guess) on whether this jump spring would be compatible with my 10AT movement?

Reverend Rob
Posted June 17, 2019 - 7:55pm

One movt  is larger than the other, but might use the same jump spring. Hard to say.

WildThng
Posted June 28, 2019 - 1:26am

Another option.... find a jeweler with a laser welder. They can weld it back with fine steel wire.

Nick W.
Posted July 17, 2019 - 11:34am

So, it looks like all my potential sources have dried up.

WildThng...Regarding your suggestion to find a jeweler with a laser welder: Is that viable for a component this small?  As I understand it, this jump spring is only slightly thicker than a human hair.

 

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