# Bi-directional self-winding mechanism, ETA2824, Seiko 7S26, others



## MikoDel (Dec 10, 2010)

Bi-directional self-winding mechanism, ETA2824, Seiko 7S26, others

I wanted to learn about the mechanics of bi-directional winding. It took some searching. With each find, I became more educated and therefore able to use more correct terminology in subsequent searches. Attached are pics and some YouTube links that illustrate how automatic watches work - how clever mechanical engineering converts two-way rotor spin into unidirectional gear movement that winds the mainspring.

It was after the purchase of my $60 Seiko SNK809 that I first saw, under magnification, the pawl levers in action. I wanted to understand these mechanics. The very sophisticated differential-like locking gears of the CGI CAD YouTube link from ZEITWINKEL is unlike any watch I own.

intro. about gear train of wristwatch - YouTube

Nicholas Hacko Watchmaker DIY Seiko 7S26 Sydney

The Mechanics of Mechanical Watches and Clocks - Ruxu Du, Longhan Xie - Google Books


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## MikoDel (Dec 10, 2010)

More good info here:
mechanical mechanism watch 2824 rolex winding bi directional gear puzzle gears tutorial movement rotor spring ETA
The Seiko Diver's 200 Meter SKX779 Featuring the 7S26 Automatic Movement

Seiko continues to amaze me. The more I "play" with my 7S36 diver the more I appreciate the perfection (near perfection?) of Seiko craftsmanship and ingenuity. It just feels like quality, any way you slice it.

I'd like to find out what differences there are (besides jewel count) between 7S2 and 7S36 Seiko mov'ts. For instance, does the auto wind mechanism work the same way?


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