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10BPAC mainspring needed

Or maybe an interchangeable part?
Anyone's help is appreciated!

Reverend Rob's picture
Reverend Rob
Panel Member
Posted August 28, 2018 - 1:12am

This is an in house Bulova movt, so it has no interchange with an ebauche- but anything like 10BPA, 10CBAC, 10BPAD use the same MS. I don't see anything on eBay, but I will check my stock and get back to you. 

SybrenAnne's picture
SybrenAnne
Posted February 27, 2019 - 9:07pm

Dear Bob,
I found a 10BA mainspring.
Do you know if this ms fits a 10BPAC movement?
With regards, Sybren

Reverend Rob's picture
Reverend Rob
Panel Member
Posted February 27, 2019 - 11:58pm

Hi Sybren,

No. The 10BPAC is an automatic and the 10BA is not. Automatic mainsprings have slipping bridles, which mean they are not anchored to the wall of the barrel. Manual wind watches are hooked to the outside wall of the barrel. The Bulova numeric/alpha calibre starts with two letters, and when they add letters, they are descriptors. After the intital two lettters, another 'A' means automatic, and a 'D' means date, that sort of thing. 

In the calibre 10BPAC, it is a base 10BP, with Automatic winding and 'C' for centre sweep hand.

The 10BPAC is also listed as having a sealed barrel, and no dimensions are given for the mainspring. The only way to know what these are is to remove the spring and measure it with calipers, although some Mat supply houses seem to have either already done this, or have an interchange list that most of us don't have.

JimDon5822
Posted August 31, 2018 - 11:17pm

I have a complete NOS Bulova 10CBAC Barrel Complete.  If you can use this for your watch PM me and I will send it your way.  

JimDon5822
Posted September 8, 2018 - 9:22pm

The mainspring got mailed Friday.  I hope it works for you.

SybrenAnne's picture
SybrenAnne
Posted February 25, 2019 - 3:41pm

I am searching for a 10BPAC main spring.
Actually for 2 main springs, since I have 2 Bulova 23's.
Does the main spring has an item number?
Is it possible to find them or to buy them somewhere ?

Thanks in advance, with regards, Sybren

JimDon5822
Posted February 27, 2019 - 10:59pm

 I searched high and low and cannot find one .  Sorry