Cartier 212P operating cam

[Jon]

Hi guys,

I wonder if anyone can help me? I've been given a Cartier Tank Americaine chronograph 2312, with a 212P quartz movement inside

 

The hands won't set because the operating cam is missing

The winding stem passes through it and when the winding stem is turn slightly, the minute and hour hands will move. How much depends if the winding stem is pulled out into the first or second position.

I've taken a picture of where the operating cam should go and have marked it with red. I also have an operating manual by Cartier, which is pretty scant on any real information that is useful

So what I would like to know is, what is the job of the operating cam? I'm assuming it makes a contact between two points

Also, does anyone know where I can get a replacement, otherwise I'll have to make one out of 0.5 mm thick brass and put a 0.8 mm square hole into it before filing it down to shape? The winding stem is 0.7 mm wide where it passes through the operating cam.

Does anyone have a better schematic of this movement, other than this I've attached?

Cartier_212P-TECH.pdf

[Jon]

I was forced to make an operating cam, which was a 3 hour job with a piece of 0.4 mm brass. It had to get honed down to 0.2 mm to fit in the slot.

Total dimensions were 1.2 x 1.2 x 0.2 mm, with a 0.7 mm square hole passing through it to accommodate the winding stem.

The last picture is with the operating cam in place. Damn fiddly work, but very gratifying seeing it work. Lord knows how much Cartier would have charged me!

[HSL]

Not easy to find parts to those  Cartier (Piaget) 212P movements.
Nice job filing that part, guess it is what it comes to with these ones.

[watchweasol]

Nice one Jon a good job well done