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Seagull ST36 Regulating/Timegrapher

Jonno65
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Jonno65 Watch Enthusiast

Jonno65

Posted
Posted

Hi All

I have also stripped and rebuilt the Seagull ST36 movement, my first, and despite breaking the screw on the click spring and buying a donor movement (new), I now have it running.  I am making a my own watch with it, also a first so I put it on the timegrapher.  I searched for the correct lift angle and I can only find the 6497 which states 44 degrees, but it also states a beat rate of 18000.  The Timegrapher auto beat rate detect says 21600.  If I manually change it to 18000 it wont detect a beat.

I am using the Weishi No. 1900 Timegrapher.

Can anyone confirm:

- The ST36 Lift Angle? (I assume the same as a 6497)

- The correct beat rate for the ST36

All the web resources, such as Lift angle databases conveniently omit any Seagull movements.

Cheers

Jon

tomh207 Distinguished Member

tomh207

Posted
Posted

@Jonno65 calibre corner shows it as 21600 BPH, no lift angle I can find either. Might be worth setting to 44, letting down the mainspring, marking the balance and adding wind bit by bit till you have 180 degrees of observed amplitude and check the timegrapher displayed amplitude is close. If not then change lift angle until it does agree with what you see on the balance. This process should confirm or allow you to find the lift angle. There are some YouTube videos on doing this.

 

caliber corner link https://calibercorner.com/seagull-caliber-st3600k/

 

Tom

JohnR725 Distinguished Member

JohnR725

Posted
Posted
17 hours ago, Jonno65 said:

The ST36 Lift Angle? (I assume the same as a 6497)

you assumed incorrectly yes it's a clone of a 6497 but which 6497? There is a later version called a 6497-2  which I assume they cloned. I'm attaching both the technical communication and the manufacturing  guide. Manufacturing guide has all sorts of interesting technical specifications don't know how closely they followed them and that also includes timing specifications. Then there's technical guide which is really a service bulletin.

 

 

ETA 6497-2 Manufacturing Information.pdf ETA 6497-2 Technical Communication.pdf

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