The complete story and why the use of the 90 degree stop was implemented on the 91mm Officiers knives in 1985 is not fully clear. I would expect it to be because of the product development,
production and versatile use. A 90 degree stop was used on the fine screwdriver from atleast the 1957 time window.
I should mention some on my feel and research then i would like to mention the
100 year anniversary in 1984 and the introduction of the SwissChamp in 1985 as well.
Plant update:
From research i did discover the increase of the Victorinox plant and the development in the 1984 time window. In many different newspapers and articles in the 1983-1985 time window there was much talk about the world interest in the product and
the interest by US presidents. You will discover the space programs at this time in history.
The Champion models and the first time i found information about the coming SwissChamp in 1985 was in
1984.