This shape is a classic result of improper installation of the spring.
The lever setting mechanism used by Elgin convertible grades is significantly different from other Elgins.
This watch had a broken setting lever spring. The remaining bit, and the replacement part, is shown here along with the screw that hold the spring in place.
This movement is an Elgin grade 93, 16 size, 11 jewels, made about 1884.
more convertible examples here!