Some SF240 evolution observations.

[Yoda]

I have had the opportunity to have a lot of SF240 movements on my bench these last 10, 15 years, both Angelus ones and Panerai movements.

One thing I have noticed is that the case screw positions have been altered over the years, and the jewel count.

1936 non alarm SW, non incabloc movement had the old case screw positions.

1947/1948 alarm incabloc had no case screw positions.

1950 incabloc had the new screw positions.

1955 incabloc had no screw positions and new barrel bridge design.

1956 incabloc had only the new case screw positions and new barrel bridge design.

Mai./Juin. 61 had both old and new screw positions and 17 jewels instead of the standard 15.

The GPF 12.55 incastar had both the old and new case screw positions and 17 jewels.

The latest made in 2005 feels a little odd, its a 15 jewel movement and the hole for winding the alarm parts is gone, it also has both the old and new case screw positions.

I wonder what will happen next, will the SF240 movement live on?

[Philip1944]

will the SF240 movement live on?
hopefully it will but this will depend on the one or two experts who continue to give us the knowledge about these fascinating movements... and a particular expert beginning with Y.

[Yoda]

I forgot some interesting details....

The Mai./Juin.61 and the GPF 12.55 had the glucydur balance, but the Mai./Juin.61 had a Brequet/overcoil hairspring and the GPF 12.55 had a free sprung hairspring. That indicates that the SF240 has had at least three types of balance wheels, the glucydur with Brequet/overcoil hairspring or free sprung hairspring, the white alloy balance wheel with the overcoil hairspring and the golden balance wheel with the flat hairspring in the KW movements. As usual, some configurations have been changed over the years, for reasons beyond my knowledge.