This project is Elgin's
grade 437, 12 size, 17 jewels, made about 1914.
The job begins with a pretty obviously broken mainspring.
This grade of Elgin is less common, and it has some unusual features. It’s
thinner than other 12 size Elgin movements for one thing. One of the ways this
is achieved is to use a thinner barrel and to mount it lower. Note the large
round cut out in the base plate. The mainspring barrel arbor on this movement
is not supported by the plate.
To accommodate the mainspring barrel cut out, the minute wheel is offset and
an intermediary gear added. The minute wheel clamp is virtually identical on
millions of Elgin 12 size movements of nearly all grades, but on this grade it
is different.
There’s a few different tools around for manipulating hairsprings, and
different ones are good in different contexts. On larger springs when
adjusting the height of the stud, as I did on this watch, the wide tweezers
pictured here are just right. The short, wide nose can securely grip the
outer coil and hold it straight, while using the other hand and regular 3C
tweezers to change the bend with a slight twist.
The ratchet wheel and mainspring barrel have an unusual design, for
Elgin.
Here is the dial side of this movement. Note how the mainspring barrel comes
all the way down through the base plate.
Project link (all the posts):
https://pluspora.com/tags/190195_et Follow all the projects in detail here:
https://pluspora.com/tags/elgintime
And the album for this project is here:
https://photos.app.goo.gl/TpjUJ5BMR4PRmwtp9
