Question about 1956 Bulova mainspring in Albatross, 10 CBAC

[JerSievers]

I have a sweet little square 1956 Bulova Albatross, came as a non-runner. 10 CBAC automatic movement. To my surprise the watch was beating wonderfully away when I opened it up, winding works was tight with old grease, but time sets fine, only issue is a bent second pinon. I may or my not fix this...anyway, stripped down and headed to the ultrasonic for a cleaning. After taking out the mainspring, which has a simple tongue end...there was more in the barrel. 

My first thought was, "bugger, I need a new mainspring." On second glance, the watch was running very strong on timegrapher and only looked to the world like it needed a little regulation. (This watch was purchased to learn, so it had to be serviced). After inspecting replacements (Images of this below too) (https://www.ebay.com/itm/164900126680?hash=item2664d03fd8:g:cLsAAOSwlgNgvDLB) and in inspection of the mainspring, it doesn't look like it broke. I think it has a "detached bridal." 

My reasoning is the replacement mainsprings only have a small tongue, and look exactly like what I had initially pulled out. The "bridal" has rounded ends and a small pip. There are no hard edges from a break, nor is there on the mainspring. There will always be a little discoloration if there is a welded tack point, there is where the tongue was installed, but not on the bridal. 

I think the "bridal" sets against the barrel wall and breaking grease controls the over wind of the automatic, the tongue of the main spring engages with the pip on bridal.

Can any one confirm my supposition is correct? There are details images of the mainspring, "Bridal" and rotor (just to confirm the movement model).

I'll show off once I am completed with restoration, it has original hands and crystal, these were only made that one year (from my research) and have a very cool retention system for the case back, pretty sure this is where it's name came from. 

[Marc]

13 minutes ago, JerSievers said:

Can any one confirm my supposition is correct?

That is quite correct. This is how main springs for auto's used to be, basically a manual wind m/s with a separate bridle.

[JerSievers]

19 minutes ago, Marc said:

That is quite correct. This is how main springs for auto's used to be, basically a manual wind m/s with a separate bridle.

Excellent, thank you for sharing your knowledge. I didn't photograph the bridle in the mainspring, should it set so the lip of the tongue grips the lip of pip (a) or sets in the gap (b)? 

(I may have done the diagram backwards, but you should get the gist.)

 

[JohnR725]

Your spring visually looks fine. At one time they made a special winder just for the short little inset part because it can be a pain to get in some time it's really stiff. Yes it has to go in the right direction so it slips properly. You also need breaking grease on the outer wall. Then I think your diagram looks right I'm just trying to figure out the wording you using? Basically put the bridle in the first the outer part with its breaking grease on the outer wall you may find that the ends actually overlap sometimes they do. Then you can just insert the spring like you would any other spring of that type and it will hook on its protruding hook on the  bridle. Otherwise you can find a replacement which should be all one piece

[JerSievers]

39 minutes ago, JohnR725 said:

Your spring visually looks fine. At one time they made a special winder just for the short little inset part because it can be a pain to get in some time it's really stiff. Yes it has to go in the right direction so it slips properly. You also need breaking grease on the outer wall. Then I think your diagram looks right I'm just trying to figure out the wording you using? Basically put the bridle in the first the outer part with its breaking grease on the outer wall you may find that the ends actually overlap sometimes they do. Then you can just insert the spring like you would any other spring of that type and it will hook on its protruding hook on the  bridle. Otherwise you can find a replacement which should be all one piece

Yep, that makes sense. Thanks!