Seiko

HIROTA, Masayuki
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Additional Information

Thanks, SJX-san and Ken-san.

There are noting to add your excellent report, but I try to add some interesting information.

SII and EPSON have own "Baked Machine" to increase hardness of steel parts. Now steel parts made by them have over 700Hv
To be exact, 740Hv. It`s the almost same as vintage Patek. As far as I know, the most hard in current mechanical movement

Good example is winging system of Cal.9S65/67/87. These movements adopt "Reverser-type" automatic system.
It's almost the same as ETA and Rolex.
Reveser-automatic, Wiser system for productivity, but has weakness in abrasion.
but wisely, Rolex gives anodized coating on its aluminum reverser.

The reason of aluminum reverser is to decrease inertia moment of that.
If inertia moment of reverser is small, winding efficiency may be drastically improved.
On the other hand, they may abrasion easier(Please remind ETA 2892-A2)
Thus Rolex gives anodized coating on its aluminum reverser. Very good solution, I think.

Now Seiko do the same way on Cal.9S65/67/87. Seiko`s reverser is very small to improve winding efficiency.
And gives special coating on reverser. Though Seiko do not want to hardness of these parts (They are not talkative),
I heard it has over 700Hv hardness. Just say wonderful.

Before, Hardness was the weak point of Japanese watches. In 60's A Japanese Institute investigated hardness of steel parts.
The best one was high end swiss watches. I mean Patek. It`s almost 740Hv. Middle-range was 600-650Hv.
Meanwhile, Japanese watch, only 580Hv. But thanks to their endeavor, now over 700Hv.

Regards,

HIROTA, Masayuki
Main contributor of Chronos Japan

Picture: Reverser of 9S67